Influence of acute pain on valence rating of words

Christoph Brodhun; Eleonora Borelli; Thomas Weiss

doi:10.1371/journal.pone.0248744

. 2021 Mar 18;16(3):e0248744. doi: 10.1371/journal.pone.0248744

Influence of acute pain on valence rating of words

Christoph Brodhun ¹, Eleonora Borelli ², Thomas Weiss ^1,^*

Editor: José A Hinojosa³

PMCID: PMC7971552 PMID: 33735235

Abstract

Numerous studies showed the effect of negative affective and pain-related semantic primes enhancing the perceived intensity of successive painful stimuli. It remains unclear whether and how painful primes are able to influence semantic stimuli in a similar way. Therefore, we investigated the effects of noxious primes on the perception of the valence of subsequent semantic stimuli. In two experiments, 48 healthy subjects were asked to give their valence ratings regarding different semantic stimuli (pain-related, negative, positive, and neutral adjectives) after they were primed with noxious electrical stimuli of moderate intensity. Experiment 1 focused on the existence of the effect, experiment 2 focused on the length of the effect. Valence ratings of pain-related, negative, and positive words (not neutral words) became more negative after a painful electrical prime was applied in contrast to no prime. This effect was more pronounced for pain-related words compared to negative, pain-unrelated words. Furthermore, the priming effect continued to affect the valence ratings even some minutes after the painful priming had stopped. So, painful primes are influencing the perception of semantic stimuli as well as semantic primes are influencing the perception of painful stimuli.

Introduction

There are numerous studies showing effects of different kinds of primes on the perception and processing of painful stimuli. Thus, the presentation of various types of stimuli with negative valence like pictures [1–5], films [6], sounds [7], and odors [8] before or during the application of painful stimuli increases pain ratings. A similar intensity-enhancing effect was shown repeatedly for pain-related words and words with negative valence [e.g. 9–12]. In contrast to neutral words, pain ratings were increased when pain-related words or words with negative valence had been shown before the application of painful stimuli. Overall, there is evidence suggesting that written words may be more suitable to elicit priming effects in contrast to pictures, spoken words or environmental sounds [13]. These results are in line with the assumptions of the motivational priming theory [14]. According to this theory, emotions can be seen as action dispositions. In this view, all emotions can be localized in a two-dimensional space, including the dimension of affective valence and the dimension of arousal (or activiation). The theory poses that defensive reflexes (including startle and reflex responses to pain) “increase in amplitude when an orgnaism is aversively motivated” (p. 372); oppositely, defensive reflexes are reduced in amplitude when the subject is positively motivated. Therefore, increased pain ratings to painful target stimuli when primed by negative or pain-associated words are a consequence of negative emotional priming.

In addition to the motivational priming, several studies have shown a more pronounced priming effect towards higher pain ratings for pain-related primes compared to negative, but pain-unrelated primes. For example, the priming of a physically identical noxious stimulus by a pain-related adjective (e.g. excruciating) results in higher pain ratings than priming by a negative adjective (e.g. hostile) [9]. Note, that both adjectives produce a similar negative valence. Therefore, the higher pain perception reported to physically identical noxious stimuli primed by pain-related as compared to similarly negative, but non-pain-related adjectives cannot be explained by the motivational priming theory alone. However, such an effect was observed for both pictures [5,15] and words [9]. The theory of neural networks provides the theoretical background for this additional negative priming effect [16]. According to this theory, past pain experiences would lead to develop an associative memory network that can affect the processing of noxious stimuli at different levels. This pain network would strengthen its connections and increase its efficacy whenever we are exposed to real or potentially real painful stimuli, or also to stimuli that semantically represent harm or threat [12]. Thus, pain-related primes could activate specific pain-related neural networks (not merely negative valence) in contrast to negative, pain-unrelated primes. Consequential, pain-related primes lead to a more prominent increase of pain ratings [9,17,18].

It remains unclear whether an effect of painful primes exists on perception and processing of the valence of words. Until now, there is no study investigating such an effect. Therefore, the current study examines a possible effect of painful primes on perception and processing of the valence of words. According to the motivational priming theory mentioned above, we hypothesized that the negative emotional aspect of painful stimuli leads to more negative valence ratings of pain-related and negative, pain-unrelated target words in contrast to neutral words. With respect to the theory of neural networks, we additionally hypothesized that this effect would be more pronounced for pain-related target words compared to negative, pain-unrelated target words. This would support findings of a pain-specific priming effect in addition to a simple emotional priming effect. This hypothesis is in line with results from Ritter et al. [9] who showed a more pronounced priming effect of pain ratings for pain-related word primes compared to negative, pain-unrelated primes.

The current study aims primarily to show the effects of painful stimuli as primes for pain-related words as targets compared to negative, pain-unrelated targets. Valence ratings of pain-related words are expected to be more negative compared to negative, pain-unrelated words after priming with painful stimuli. To assess the effects, we conducted two experiments. In the first experiment we wanted to investigate whether an effect of painful primes on word valence rating exists. If such an effect could be observed, the question remains for how long the priming with painful stimuli continues to effect valence ratings of words. Previous studies have demonstrated long-lasting effects of different types of priming for hours or even a day, e.g. [19]. Consequently, the goal of the second experiment was to determine whether a possible effect lasts even without the painful stimulation and to identify possible moderating variables.

Experiment 1

Participants

Twenty-five volunteers (17 female and 8 male, 24.4 ± 3.7 years old) participated in experiment 1. All participants were healthy right-handed native German speaking university students recruited via social media and mailing list. Written informed consent for participating according to the Declaration of Helsinki was obtained from all participants. The experiments were approved by the ethics committee of the Friedrich Schiller University Jena (vote No. FSV 14/04) prior to study commencement.

All subjects were free of acute or chronic pain according to a Likert scaled (0–10) life pain questionnaire and free of pain medication. A clinical interview and the additionally applied Beck depression inventory (BDI-2) [20] revealed no depressive symptoms in the subjects. Therefore, none of the participants was excluded due to a priori criteria of indices for chronic pain experiences or previous critical pain experiences or BDI-2 scores above 18. Subjects received a monetary reimbursement of 8.50 Euro per hour.

Sample size was calculated using a tool for a priori analyses [21]. Considering the fact that there are no studies investigating the effect of painful priming on the valence of words, we used previous results of our research group investigating the effect of affective priming on pain ratings as a starting point. Considering the number of measurements for each person we calculated a necessary sample size of approximately 20 participants with α = 0.05 and power = 0.9.

Pain stimuli

Both in experiment 1 and 2, a constant current stimulator (DS7H; Digitimer, Welwyn Garden City, UK) generated monophasic electrical stimuli for 3.5 s duration with a frequency of 200 Hz. These stimuli were applied to the tip of the middle finger of the left hand using the method of intracutaneous stimulation [11,22,23]. Therefore, an isolated golden pin electrode (diameter: 0.95 mm, length: 1 mm) was inserted into a small epidermal cavity of 1 mm diameter and about 1 mm depth and fixed with adhesive tape. This was done to reduce skin resistance to elicit a pain sensation. Care was taken to not cause any bleeding. A flexible stainless-steel electrode, fixed loosely around the first finger joint of the middle finger, served as reference electrode.

To determine the pain sensitivity of the participants, electrical stimuli were given according the following procedure. The subjects received an electrical stimulus and were asked to rate the stimulus after it had stopped. The intensity of stimulation was changed in accordance to the rating of the subjects. We used the method of limits to determine perception thresholds for somatosensory sensation and an intensity to evoke moderately painful perceptions (details below).

Rating scale

The subjects were asked to rate each stimulus on a modified Ellermeier scale [24,25]. This scale consists of eight verbal categories. Each category is subdivided by numbers (0, no sensation; 1–10, just perceived but not painful; 11–20, clearly perceived but not painful; 21–30, very mildly painful; 31–40, mildly painful; 41–50, moderately painful; 51–60, strongly painful; 61–70, very strongly painful; for a more detailed description of the scale–see Ritter et al. [24]). The scale was presented on the same computer screen where the words and the valence scale were presented later in the experiment. The subjects were prompted to give just the numerical rating verbally.

Somatosensory perception threshold

Starting with 0 mA, stimulation successively raised in steps of 0.05 mA until the subject reported a first sensation, i.e. the rating was >0 for the first time (usually not painful). Thereafter, stimulation was decreased by 0.05 mA until the subjects gave a pain rating of 0 again. Such increases and decreases were repeated four times around the threshold for a reported sensation. The last three intensities were used to determine the threshold.

Intensity to evoke moderately painful perceptions

After the determination of the somatosensory perception threshold, the intensity was successively raised in steps of 0.5 mA until the second threshold, fixed at a rating of 50, indicating the boundary of moderate pain to strongly painful pain, was determined. We used a rating of 50 as we expected some habituation in the course of the main experiment. We applied the same procedure as for the first threshold (increasing and decreasing intensity four times). The intensity threshold identified this way was used as the electrical stimulus in the experiment. A stimulus of moderate pain was used because it was shown that priming effects with electrical stimulation only occur for clearly painful and not for lower intensity stimulation slightly above the pain threshold [4,9,11].

Word stimuli

We used 40 German adjectives as target stimuli in four categories– 10 pain-related (e.g. excruciating), 10 negative (e.g. hostile), 10 neutral (e.g. cubical), and 10 positive adjectives (e.g. exhilarating), as in previous studies [11,18]. Between categories, words were matched with respect to their word frequency and word length. Valence and arousal qualities were balanced for pain-related and negative words. Furthermore, arousal qualities of pain-related, negative, and positive words were balanced (for a more detailed description of the method–see Richter et al. [18]). Adjectives were shown in a pseudo-randomized order. We assured that not more than two consecutive words belonged to the same category to prevent summation effects.

Study design

Experiment 1 was divided into four blocks of 100 trials. Each block lasted 14 minutes. The rest interval between blocks was not longer than 1 minute. During this time, subjects were able to drink a glass of sparkling water or just to relax. Taken together, the experiment proper performed in a special experimental noise-attenuating cabin (Industrial Acoustics Company GmbH, Niederkrüchten, Germany) took approximately 1 hour, while the whole experiment (including preparation, questionnaires, determination of the stimulus intensity) no longer than 2 hours.

Structure of a trial

In each trial, an adjective was presented on the screen for 500 ms for the participants to read (Fig 1).

The offset of the presentation of the adjective was followed by 2.5–3.5 s of black screen, which was followed by the presentation of the valence scale (Self-Assessment Manikin, 1 = most positive, 9 = most negative; see [26]) to assess the valence of the shown word. The subjects gave their answer verbally. All ratings of the subjects were entered on the keyboard by the experimenter. Additionally, on average every seventh trial participants were shown the modified Ellermeier scale [24,25] to rate the pain sensation verbally. Care was taken that every word category had the same number of pain ratings in the course of the experiment. At the end of the trial, there was a black screen for 1–2 s (second jitter) before the next trial started.

This primary structure of the trial was modulated by the presence or absence of an antecedent painful stimulation. Half of the trials did not have painful electrical stimulation before presentation of the adjective, the other half did. In the latter condition, the trial was as described above, just with additional electrical stimulation. Painful electrical stimulation started at the beginning of the trial, before an adjective was presented. Between one and two seconds (first jitter) after the onset of the electrical stimulation, an adjective was presented for 500 ms. The electrical stimulation lasted throughout the presentation of the adjective. The presentation of the scales was as described above.

In total, 200 trials with painful electrical stimulation and 200 trials without were conducted. The order of trials with and without painful electrical stimulation was randomised to avoid effects of expectations (for those effects–see [27]). So, each word was presented five times with painful electrical stimulation and five times without. Jitters were randomized and were applied to prevent a precise prediction of the onset of the next stimulus. Immediately after the last trial of the last block, subjects were given three minutes to recall any words shown during the experiment. The experiment was controlled by the software Presentation (Version 14.5, Neurobehavioral Systems, Inc., Albany, CA, USA).

Data analysis

To test the effects of the pain stimuli both on the valence ratings and pain ratings, repeated measures analyses of variance (ANOVA) were applied. Within-subject factors were Category (pain-related, negative, neutral, and positive adjectives), Word (ten adjectives in each category), Prime (stimulation vs. no stimulation), and Repetition (first to fifth presentation of the adjective in the time course of experiment for both levels of factor Prime). Significant main effects were followed by post-hoc t-tests for paired samples according to our hypotheses (two-tailed, Bonferroni-Holm corrected). Normal distribution of all dependent variables was tested using the Shapiro-Wilk-Test. All variables met the assumption of normal distribution. In addition, the number of recalls after the experiment was also compared between word categories using an ANOVA for repeated measures. To account for violations of sphericity, the Greenhouse-Geisser procedure was used to correct degrees of freedom.

Results of Experiment 1

ANOVA for valence ratings revealed significant main effects for Prime (F_{(1; 24)} = 8.91; p = 0.006; η_p² = 0.27), Category (F_{(1.9; 46)} = 321.97; p < 0.001; η_p² = 0.93), Word (F_{(4.9; 118)} = 10.41; p < 0.001; η_p² = 0.30), and Repetition (F_{(1.5; 36.8)} = 7.61; p = 0.004; η_p² = 0.24) as well as significant interactions for Prime*Category (F_{(1.7; 39.9)} = 3.87; p = 0.036; η_p² = 0.14), and Category*Word (F_{(9.5; 227.3)} = 8.07; p < 0.001; η_p² = 0.25). As the factor Prime only has two levels, the main effect showed a significant contrast stimulation vs. no stimulation, with more negative valence ratings (mean ± standard errors [S.E.]) of 5.39 ± 0.11 for stimulation vs. 5.14 ± 0.11 for no stimulation. Regarding the main effect for Category, t-tests between the levels of this factor revealed highly significant differences for all contrasts except for the contrast pain-related vs. negative words (t = -1.86; p = 0.076). The other contrasts for the main effect for Category (category with more negative valence ratings is mentioned first for each contrast): pain-related vs. neutral words (t = 14.54; p < 0.001), pain-related vs. positive words (t = 21.05; p < 0.001), negative vs. neutral words (t = 16.64; p < 0.001), negative vs. positive words (t = 21.32; p < 0.001), and neutral vs. positive words (t = 11.99; p < 0.001). Regarding the main effect for Repetition, t-tests between the levels of this factor revealed two significant differences. Repetition 1 showed lower valence ratings vs. repetition 4 (t = -3.74; p = 0.011) and vs. repetition 5 (t = -3.15; p = 0.039). The other contrasts for the main effect for Repetition: repetition 1 vs. repetition 2 (t = -2.44; p = 0.162), repetition 1 vs. repetition 3 (t = -2.81; p = 0.073), repetition 2 vs. repetition 3 (t = -2.33; p = 0.182), repetition 2 vs. repetition 4 (t = -1.46; p = 0.755), repetition 2 vs. repetition 5 (t = -0.71; p = 1), repetition 3 vs. repetition 4 (t = -0.13; p = 1), repetition 3 vs. repetition 5 (t = 0.36; p = 1), repetition 4 vs. repetition 5 (t = 1.33; p = 0.811). Regarding the main effect for Word, corrected t-tests between the levels of this factor revealed no significant differences for any contrast. Regarding the interaction effect Category*Word, several significant contrast were found (post-hoc tests are presented in S2 Table in the supporting information). The interaction effect for Prime*Category revealed significantly higher valence ratings with painful stimulation vs. no stimulation for pain-related (t = 3.92; p = 0.003), negative (t = 3.12; p = 0.014), and positive words (t = 2.98; p = 0.014), but not for neutral words (t = 1.82; p = 0.080) (Fig 2). To further investigate this effect, we computed difference variables, i.e. the difference between the valence ratings with pain stimulation and the valence ratings without pain stimulation and used these difference variables to compare the effects of pain stimulation between categories. ANOVA for this difference valence ratings revealed a significant effect (F_{(3; 39.9)} = 3.87; p = 0.036; η_p² = 0.14). We found lower difference valence ratings for neutral vs. positive words (t = -3.12; p = 0.014), negative vs. positive words (t = -2.44; p = 0.046), and higher difference valence ratings for pain-related vs. negative words (t = 2.44; p = 0.046) (Fig 3). The contrasts pain-related vs. neutral words (t = 1.19; p = 0.355), pain-related vs. positive words (t = -1.21; p = 0.355), and negative vs. neutral words (t = -0.26; p = 0.400) were not significant.

Fig 2 — Data are reported as mean (SE); **: p < 0.01, *: p < 0.05.

Fig 3 — Data shown as differences of valence ratings for words with painful primes vs. the same words without painful primes. Data are reported as mean (SE); *: p < 0.05.

ANOVA for pain ratings revealed significant main effects for Prime (F_{(1; 24)} = 312.99; p < 0.001; η_p² = 0.93) and Category (F_{(3; 72)} = 4.39; p = 0.007; η_p² = 0.15), but no interaction. As the factor Prime only has two levels, the main effect showed a significant contrast stimulation vs. no stimulation, with higher pain ratings (mean intensity ± S.E.) of 48.10 ± 2.53 for stimulation vs. 4.17 ± 0.99 for no stimulation. Regarding the main effect for Category, t-tests between the levels of this factor revealed only one significant contrast with higher pain ratings for pain-related vs. neutral words (t = 3.93; p = 0.015) (Fig 4). The other contrasts for the main effect for Category: pain-related vs. negative words (t = 2.52; p = 0.093), pain-related vs. positive words (t = 2.20; p = 0.152), negative vs. neutral words (t = 1.18; p = 0.498), negative vs. positive words (t = 0.13; p = 0.896), and neutral vs. positive words (t = -1.72; p = 0.292).

Fig 4 — Data are reported as mean (SE); *: p < 0.05.

ANOVA of the number of recalls per word category after the experiment showed a significant effect (F_{(3; 72)} = 18.45; p < 0.001; η_p² = 0.43). Only the contrasts of pain-related words (mean recalled words (± S.E.) of 2.8 ± 0.36) vs. negative (5.1 ± 0.33) (t = -4.56; p < 0.001), neutral (4.76 ± 0.31) (t = -4.02; p = 0.002), and positive words (5.76 ± 0.27) (t = -7.78; p < 0.001) were significant with fewer recalls for pain-related words than all other categories. The other contrasts for this effect: negative vs. neutral words (t = 1.04; p = 0.308), negative vs. positive words (t = -1.83; p = 0.161), and neutral vs. positive words (t = -2.40; p = 0.073).

Discussion to Experiment 1

We will mainly discuss the results of Experiment 1 with respect to aim of the study and to the two major theories described in the introduction. Several other aspects will be considered in the general discussion.

The main effect for Category revealed highly significant results for all contrasts of this factor except for the contrast pain-related vs. negative words. This result can be seen as manipulation check. It demonstrates the successful choice of stimulus material as in previous research [9,11,17,18].

Valence ratings of words became more negative after a painful electrical prime was applied in contrast to no prime (Fig 2, main effect of Prime). This corresponds to the motivational priming theory [14]. The applied primes might lead to an activation of neural structures associated with negative affect. These results are in accordance with experimental findings supporting the assumptions of the motivational priming theory [e.g. 10,11]. The current study is the first to show this effect using painful electrical primes.

Results depicted in Fig 3 and the interaction Prime*Category indicate that painful primes do have a larger effect on valence ratings to succeeding pain-related words compared to negative, pain-unrelated words. This means that painful primes do not only lead to a simple emotional priming effect as predicted from emotional priming theory [14]. According to this theory, one would have expected a similar priming effect due to similar pain intensity and similar negative valence of the target words. However, we found an additional priming effect of noxious stimulation to pain-related adjectives; i.e., painful primes do not only lead to a more general negative valence rating, but to an exceedingly negative valence rating when followed by pain-related targets in contrast to negative, pain-unrelated targets. This result represents the answer to the major question of this investigation. The observed additional priming effect could be explained by the theory of neural networks [16]. This result is also in line with previous findings presenting higher pain ratings to physically identical noxious stimuli when pain-related adjectives served as primes in comparison to similarly negative adjectives [9].

No significant interaction between the factors Word and Prime was found. This indicates that the above-mentioned effect of the factors Prime and Category on valence ratings are not just due to a few items generating a strong effect. It rather shows a more general effect not just of individual words, but of word categories.

We found a main effect for Repetition. Further analysis revealed only two significant contrasts. Valence ratings were higher in repetition 4 and repetition 5 in contrast to repetition 1. This is an unexpected finding. It is not clear why this effect occurs only during repetitions 4 and 5.

Regarding pain ratings, we found higher ratings for trials with painful stimulation vs. no stimulation (main effect Prime). This means the manipulation with painful stimuli worked. Concerning factor Category, only the contrast pain-related vs. neutral words was statistically significant. So, for pain ratings we did not find a more pronounced effect for pain-related words compared to negative, pain-unrelated words (Fig 4), as described by Ritter et al. [9]. This may be because we did not specifically investigate the effects on pain ratings and, therefore, asked the participants merely in 60 out of 400 trials for a pain rating. So, the estimators may not have been robust enough. Subsequent power analyses for pain ratings with the found effect size revealed that additional 34 participants would have sufficed to reach a statistically significant contrast of pain-related words compared to negative, pain-unrelated words. Pain stimuli served as the prime, and pain ratings were not the target in our experiments. This also may have led to the absence of the effect as the effect might also be shorter-lasting. To analyse this aspect, further experiments are necessary.

Experiment 2

Participants, word stimuli, study design

Twenty-six volunteers (14 female and 12 male, 24.2 ± 4.5 years old) participated in experiment 2.

Generally, the procedure of experiment 2 was the same as in experiment 1 including similar written informed consent, intensity of pain stimuli used, and words used in the experiment. We also used the same scales as in experiment 1 (Fig 1). However, in addition to the 400 trials of Exp. 1 mentioned above, a pre and a post measure of the valence rating was added, each consisting of 80 trials (each of the words mentioned above was shown two times before and after the main experiment). The order of the words was pseudo-randomized as described above. In these two additional blocks, no painful electrical stimulation was applied. The pre-block served as a baseline for the valence rating, whereas the post-block served as a measure for the period the effect lasted. The post-block was split in half for analysis to examine the length of the effect (first 40 words in post-block 1 and the following 40 words in post-block 2). Each post-block lasted approximately six minutes.

In total, three subjects were excluded in experiment 2. One participant (female) did not reach the threshold for experiencing pain although the stimulator was at maximum. Two subjects (female and male) sensitised too much, the pain became too strong and the experiments were stopped by the experimenter because of the a priori criterion of a pain rating exceeding 70 on the modified Ellermeier scale. So, a total of twenty-three subjects was analysed in experiment 2 (12 female and 11 male, 24.6 ± 4.4 years old).

Measures in Experiment 2

In addition to the above-mentioned recall questionnaire at the end of the experiment, several other questionnaires known to possibly influence pain processing were completed to identify possible moderating variables. The activation and inhibition system was assessed with the Behavioral Approach/Inhibition System Scale [28] because it is thought to play an important role in pain processing in both healthy participants and chronic pain patients [29,30]. Given the wealth of studies attesting a role of empathy in elaborating pain-related information (for an overview, see [31]), we also assessed the individual dispositions for empathy with the Interpersonal Reactivity Index [32]. Moreover, given the subjective nature of pain perception, individual differences in pain anxiety and catastrophizing were assessed with the Pain Anxiety Symptoms Scale [33] and the Pain Catastrophizing Scale [34].

Data analysis

Data analysis was performed with an ANCOVA with similar factors as in Experiment 1 (within-subject factors Category, Word, Prime, and Repetition; however, the effects on the valence ratings were additionally examined by the within-subject factor Block (pre-block, main experiment, post-block 1, and post-block 2). Significant main effects were followed by post-hoc t-tests for paired samples according to our hypotheses (two-tailed, Bonferroni-Holm corrected).

As we have demonstrated effects in Exp. 1, we also used some parameters that sometimes have effects on pain ratings to exclude their influence on our results. Therefore, gender and ratings in individual assessment scales (Pain Catastrophizing Scale, Interpersonal Reactivity Index, Pain Anxiety Symptoms Scale, Behavioral Approach/Inhibition System) were used as covariates. To account for violations of sphericity, the Greenhouse-Geisser procedure was used to correct degrees of freedom.

Results of Experiment 2

The structure of the results of the middle part of experiment 2 (main experiment of factor Block) was similar to that of experiment 1. ANCOVA for valence ratings revealed significant main effects for Prime (F_{(1; 22)} = 12.56; p = 0.002; η_p² = 0.36), Category (F_{(1.68; 36.9)} = 211.66; p < 0.001; η_p² = 0.91), and Word (F_{(5.2; 114.3)} = 8.80; p < 0.001; η_p² = 0.29) as well as significant interactions for Category*Word (F_{(9; 198.2)} = 5.76; p < 0.001; η_p² = 0.21) and Prime*Category (F_{(2.2; 47.5)} = 4.94; p = 0.009; η_p² = 0.11). Interestingly, differing from experiment 1, there was no main effect for Repetition (F_{(1.8; 40.1)} = 1.13; p = 0.327; η_p² = 0.05). Regarding pain ratings, we found significant main effects for Prime (F_{(1; 22)} = 174.63; p < 0.001; η_p² = 0.89) and Category (F_{(1.9; 41.2)} = 4.52; p = 0.008; η_p² = 0.10), but no interaction. Post-hoc analyses regarding the significant interaction effects were similar to experiment 1 and because of that are not given in detail here.

The main reason for realizing this second experiment was to analyze changes in the valence ratings between the pre-block, the main experiment (just trials without painful stimulation), post-block 1, and post-block 2. ANCOVA revealed a significant main effect both for Block (F_{(3; 66)} = 3.28; p = 0.026; η_p² = 0.13) and Category (F_{(3; 66)} = 205.92; p < 0.001; η_p² = 0.90), but no interaction. The main effect for Block showed lower valence ratings pre-block vs. post-block 1 (t = -2.37; p = 0.027), main experiment vs. post-block 1 (t = -2.74; p = 0.012), and higher valence ratings post-block 1 vs. post-block 2 (t = 2.63; p = 0.015) (Fig 5). The other contrasts for the main effect for Block: pre-block vs. main experiment (t = -1.37; p = 0.190), pre-block vs. post-block 2 (t = -0.90; p = 0.380), and main experiment vs. post-block 2 (t = 0.03; p = 0.970). The main effect for Category showed only highly significant contrasts, except for the contrast pain-related words (mean valence rating (± S.E.) of 6.9 ± 0.14) vs. negative words (7.0 ± 0.14), which was not significant (t = -0.79; p = 0.437). Mean valence rating (± S.E.) for neutral words was 4.6 ± 0.11 and for positive words 2.4 ± 0.17 with following contrasts: higher valence ratings for pain-related words vs. neutral words (t = 12.91; p < 0.001), pain-related words vs. positive words (t = 16.17; p < 0.001), negative words vs. neutral words (t = 12.93; p < 0.001), negative words vs. positive words (t = 16.38; p < 0.001), and neutral words vs. positive words (t = 11.18; p < 0.001).

Fig 5 — Data are reported as mean (SE); *: p < 0.05.

None of the various covariates (Gender, Pain Catastrophizing Scale, Interpersonal Reactivity Index, Pain Anxiety Symptoms Scale, Behavioral Approach/Inhibition System) had any significant effect on the results mentioned above.

Discussion to Experiment 2

We were able to replicate most of the findings of experiment 1, especially those with respect to our primary aim and hypothesis. We will not replicate the discussion on these results here. However, in contrast to experiment 1 we did not find any significant effects concerning factor Repetition in experiment 2. So, the question whether the repetition of a word influences valence ratings in combination with the application of a painful prime remains unanswered.

As one of the major goals of Experiment 2 was to assess the after-effects of the painful stimulation, we specifically selected and analyzed valence ratings for trials without painful stimulation (as the pre- and the post-blocks did not include trials with painful stimulation) and found a main effect of Block. The negative priming continued to affect the valence ratings even some minutes after the painful priming had stopped as shown in experiment 2. The overall valence ratings are most negative in post-block 1, after the painful electrical stimulation of the main experiment stopped (see Fig 5). So, the painful priming does not only affect valence ratings directly as short-term priming effect, but also leads to more negative valence ratings during a certain timeframe after the end of the priming. Long-term priming effects are known in several time scales so that this result is in line with previous research (for an overview on long-term priming, see [35]). After this time (i.e. in post-block 1), valence ratings decreased almost to baseline level in post-block 2.

We found no significant effect of the various covariates on the results. The heeded covariates are known to influence pain ratings as mentioned above. On the one hand, we can exclude these variables as having influenced our results significantly. On the other hand, one might wonder why these variables influence pain ratings in other studies. The reason for this is probably that effects are quite low and are often visible only in larger groups [36,37]. Furthermore, we did not focus on pain ratings in this study, but on valence ratings to target words. This might be another reason for the absence of effects of the covariates.

Overall discussion

We investigated the effect of painful stimuli on valence ratings of succeedingly presented adjectives of different meaning and observed a priming effect of painful stimuli on the valence of adjectives. Importantly, this effect is more pronounced for pain-related words compared to negative, pain-unrelated words. The priming effect continued for a several minutes after the painful priming had stopped.

Both experiments reveal a priming effect of painful stimuli on valence ratings of succeedingly presented adjectives irrespective from the meaning of the word (Fig 2). This effect is in line with the emotional priming theory [14] as painful stimuli usually induce negative emotions [38]. This change in valence was visible for all categories of adjectives (significant for neutrals when concatenating both experiments).

The most important result with respect to the primary aim of this study is the more pronounced priming effect of painful stimuli on valence ratings to succeedingly presented pain-related adjectives as compared to negative adjectives. This was found in both experiments. As mentioned earlier, painful primes do not only lead to a simple emotional priming effect similar for negative and pain-related adjectives as predicted from emotional priming theory [14], but to an additional priming effect of noxious stimulation on valence ratings to pain-related adjectives. This additional priming effect could be explained by the theory of neural networks [16]. An associative memory network will be developed as a result of past pain experiences. This network would strengthen its connections and increase its efficacy whenever we are exposed to real or potentially real painful stimuli, or also to stimuli that semantically represent harm or threat [12]. Thus, painful stimuli used in our experiment as primes could activate specific pain-related neural networks. The additional activation of a semantic network associated specific pain-relatedness (pain-related adjectives) will probably lead to a stronger activation in this network compared to negative, but pain-unrelated primes. As negative valence is one component of pain processing, this will result in more negative valence ratings for pain-related adjectives. In a similar direction, Becker et al. [39] also suggested a neural network model to explain long-term priming effects. They proposed that each time a word is processed on a semantic level, this processing will result in light increase of weights to assess this network. Combined with the priming by physical stimuli that more or less specifically activate such a network (at least, more than just networks for negative adjectives), this stronger or deeper activation might result in a more negative valence. Moreover, our results are in line with studies investigating the effect of semantic primes on painful stimuli [e.g. 9–11,17,18,40]. In these studies, primes with negative valence (pain-related and negative) not only increased pain ratings for following pain stimuli, but also pain stimuli increase the negative valence of following semantic pain-related and negative stimuli. Therefore, this could describe a vicious circle for the origin, development and perpetuation of chronic pain. Felt pain might be described by patients with pain-related words, which increases internal pain ratings. In turn, these increased pain ratings might lead to more negative internal valence ratings of pain-related words, which again might lead to an increase of internal pain ratings [41]. Of course, more detailed research is required to support this hypothesis, especially in patients [40,41]. While positive words were rated less positive after painful stimulation in accordance with the motivational priming theory [14], it was one unexpected result of this study that the negative priming effect of painful stimulation was maximal for positive words in both experiments (Fig 3). Several reasons might account for this result. On the one hand, positive words are probably most unexpected with respect to their valence. From the point of view of theory of predictive coding [42–44], there is less prediction error with respect to valence after a painful stimulus (evoking negative valence) in a plausible order from pain-related and negative over neutral to positive adjectives. In contrast, this prediction error is different in trials without a painful stimulus. Here, the discrepancy is minimal for neutral adjectives and roughly similar for the other types of adjectives as they all have the same valence difference to neutral adjectives. One might discuss whether in these trials the prediction is somewhat between neutral and negative as only trials occur without or with painful stimulation before presentation of an adjective. In any case, a prediction error will lead to an activation of higher centers in processing hierarchy, requesting for salience and to actualization of expectations. This results in larger cognitive load which might have effects on valence (and the perception of pain). On the other hand, the age of acquisition (AoA) might have influenced our results. AoA is an important variable because there exists a negative correlation between AoA and valence, i.e., positive words tend to be acquired earlier in life than negative words [45–48]. This effect would possibly also allow to provide a deeper network for positive words which per se might lead to deeper processing. This deeper processing together with the discrepancy of valence described above might also explain the unexpected priming result of painful stimulation to positive adjectives. Unfortunately, no German database containing the AoA of our adjectives is available. So, to test this possible effect, we conducted a rating study on a sample of 32 native German speaking university students and postgraduates (18 female and 14 male, 26.6 ± 4.3 years old). Participants were asked to rate the AoA of all words used in this study. Six versions of the questionnaire with different randomizations were administered to ensure the absence of order effects. Instructions and questionnaire were similar to the study of Birchenough, Davies, and Connelly [49]. With respect to AoA, we found no significant effect of Category (F_{(3; 93)} = 1.57; p = 0.202; η_p² = 0.05). So, the AoA of the adjectives used in this study do not seem to differ significantly with respect to Category (AoA mean (± S.E.) of 5.6 ± 0.10 for pain-related words, 5.3 ± 0.11 for negative words, 5.5 ± 0.09 for neutral words, and 5.4 ± 0.08 for positive words).

Limitation and future directions

The current study shows clear systematic priming effects; however, effect sizes are relatively small. This may be because, in the particular group of healthy young individuals, the modulation of the perception of painful stimuli is less influenced by painful primes. Studies indicate a more pronounced priming effect of pain-related primes versus negative, pain-unrelated primes in patients with chronic pain compared to healthy controls [1,17,40]. It appears that associative learning networks regarding pain experiences are stronger in patients with chronic pain compared to healthy controls. Therefore, chronic pain patients show larger priming effects for pain-related primes versus negative, pain-unrelated primes. Future studies might investigate the effects in patients with chronic pain.

Only electrical painful stimuli were used as primes in the present study. The application of a greater variety of painful primes (e.g. heat, cold, pressure) could generalize the findings for other qualities of pain.

The sample of the current study consists only of healthy young people. As mentioned above, further investigations should focus on chronic pain patients.

In experiment 1, we found higher valence ratings in repetition 4 and repetition 5 in contrast to repetition 1. In contrast, we did not find significant effects concerning factor Repetition in experiment 2. Future research should investigate a possible order effect and clarify the question whether it was a random effect in experiment 1 or not.

Originally, the adjectives used in this study were matched with respect to word frequency, length, number of syllables, absolute amount of valence, arousal, and unambiguousness [18]. AoA for the adjectives were measured in a separate sample with different participants. In future studies, AoA as well as other variables like abstractness or imageability should be taken into account when selecting the adjectives used as stimuli because these other parameters might have influence on the results, too.

We used various questionnaires known to influence pain processing as moderating variables and found no influence. As mentioned above, this might be due to the fact that these variables influence pain ratings, not valence ratings. In future studies, other more suitable variables could be identified and considered. Furthermore, analysis of the recall test after the experiment revealed that pain-related words were recalled significantly less compared to negative, neutral, or positive words. This might hint a selective memory effect for each of the word categories, e.g. by AoA (as stated earlier). Future research could investigate the existence and character of such an effect.

Conclusion

In summary, the motivational priming theory and the theory of neural networks are also applicable to painful primes combined with semantic stimuli. The current study showed the influence of painful primes on perception and processing of the valence of words. Painful primes lead to more negative valence ratings of pain-related and negative, pain-unrelated words in contrast to neutral words. This effect is stronger for pain-related compared to negative, pain-unrelated words and lasts even for some minutes after the painful priming stopped.

Supporting information

S1 Table. Valence ratings (mean ± SD) of each word in the main experiment.

(PDF)

Click here for additional data file.^{(55.5KB, pdf)}

S2 Table. Corrected p-values for contrasts regarding interaction effect Category*Word in the main experiment.

(PDF)

Click here for additional data file.^{(46.8KB, pdf)}

Acknowledgments

We thank Mr. Holger Hecht for his valuable work in the technical preparation of this study, MSc Maria Geisler and BSc Ani Tamir Abou Seif for their help during the preparation of the revision of the manuscript.

Data Availability

All data are given in the Ms and the Supplementary material.

Funding Statement

The authors received no specific funding for this work.

References

1.Arnold BS, Alpers GW, Suss H, Friedel E, Kosmutzky G, Geier A, et al. Affective pain modulation in fibromyalgia, somatoform pain disorder, back pain, and healthy controls. Eur J Pain. 2008;12(3): 329–38. 10.1016/j.ejpain.2007.06.007 [DOI] [PubMed] [Google Scholar]
2.Rhudy JL, Williams AE, McCabe KM, Russell JL, Maynard LJ. Emotional control of nociceptive reactions (ECON): Do affective valence and arousal play a role? Pain. 2008;136(3): 250–61. 10.1016/j.pain.2007.06.031 [DOI] [PubMed] [Google Scholar]
3.Kenntner-Mabiala R, Weyers P, Pauli P. Independent effects of emotion and attention on sensory and affective pain perception. Cogn Emot. 2007;21(8): 1615–29. [Google Scholar]
4.Godinho F, Magnin M, Frot M, Perchet C, Garcia-Larrea L. Emotional Modulation of Pain: Is It the Sensation or What We Recall? J Neurosci. 2006;26(44): 11454–61. 10.1523/JNEUROSCI.2260-06.2006 [DOI] [PMC free article] [PubMed] [Google Scholar]
5.de Wied M, Verbaten MN. Affective pictures processing, attention, and pain tolerance. Pain. 2001;90(1–2): 163–72. 10.1016/s0304-3959(00)00400-0 [DOI] [PubMed] [Google Scholar]
6.Weisenberg M, Raz T, Hener T. The influence of film-induced mood on pain perception. Pain. 1998;76(3): 365–75. 10.1016/S0304-3959(98)00069-4 [DOI] [PubMed] [Google Scholar]
7.Roy M, Peretz I, Rainville P. Emotional valence contributes to music-induced analgesia. Pain. 2008;134: 140–7. 10.1016/j.pain.2007.04.003 [DOI] [PubMed] [Google Scholar]
8.Villemure C, Slotnick BM, Bushnell MC. Effects of odors on pain perception: deciphering the roles of emotion and attention. Pain. 2003;106(1–2): 101–8. 10.1016/s0304-3959(03)00297-5 [DOI] [PubMed] [Google Scholar]
9.Ritter A, Franz M, Miltner WHR, Weiss T. How words impact on pain. Brain Behav. 2019;9(9). 10.1002/brb3.1377 [DOI] [PMC free article] [PubMed] [Google Scholar]
10.Swannell ER, Brown CA, Jones AK, Brown RJ. Some Words Hurt More Than Others: Semantic Activation of Pain Concepts in Memory and Subsequent Experiences of Pain. J Pain. 2016;17(3): 336–49. 10.1016/j.jpain.2015.11.004 [DOI] [PubMed] [Google Scholar]
11.Richter M, Schroeter C, Puensch T, Straube T, Hecht H, Ritter A, et al. Pain-related and negative semantic priming enhances perceived pain intensity. Pain Res Manag. 2014;19(2): 69–74. 10.1155/2014/425321 [DOI] [PMC free article] [PubMed] [Google Scholar]
12.Dillmann J, Miltner WH, Weiss T. The influence of semantic priming on event-related potentials to painful laser-heat stimuli in humans. Neurosci Lett. 2000;284(1–2): 53–56. 10.1016/s0304-3940(00)00957-5 [DOI] [PubMed] [Google Scholar]
13.Dorjee D, Devenney L, Thierry G. Written words supersede pictures in priming semantic access: A P300 study. Neuroreport. 2010;21: 887–91. 10.1097/WNR.0b013e32833da46a [DOI] [PubMed] [Google Scholar]
14.Lang PJ. The emotion probe: Studies of motivation and attention. Am Psychol. 1995;50(5): 372–85. 10.1037//0003-066x.50.5.372 [DOI] [PubMed] [Google Scholar]
15.Ogino Y, Nemoto H, Inui K, Saito S, Kakigi R, Goto F. Inner experience of pain: imagination of pain while viewing images showing painful events forms subjective pain representation in human brain. Cereb Cortex. 2007;17(5): 1139–46. 10.1093/cercor/bhl023 [DOI] [PubMed] [Google Scholar]
16.Hebb DO. Organization of behavior. New York: Wiley; 1949. [Google Scholar]
17.Eck J, Richter M, Straube T, Miltner WH, Weiss T. Affective brain regions are activated during the processing of pain-related words in migraine patients. Pain. 2011;152(5): 1104–13. 10.1016/j.pain.2011.01.026 [DOI] [PubMed] [Google Scholar]
18.Richter M, Eck J, Straube T, Miltner WH, Weiss T. Do words hurt? Brain activation during the processing of pain-related words. Pain. 2010;148(2): 198–205. 10.1016/j.pain.2009.08.009 [DOI] [PubMed] [Google Scholar]
19.Cave CB, Squire LR. Intact and long‐lasting repetition priming in amnesia. J Exp Psychol Learn Mem Cogn. 1992;18: 509–520. 10.1037//0278-7393.18.3.509 [DOI] [PubMed] [Google Scholar]
20.Hautzinger M, Keller F, Kühner C. Beck Depressions-Inventar: BDI II. Revision. Frankfurt am Main: Harcourt Test Services; 2006. [Google Scholar]
21.Hemmerich, W. (2020). StatistikGuru: Stichprobengröße für die ANOVA mit Messwiederholung berechnen. Retrieved from https://statistikguru.de/rechner/stichprobengroesse-anova-mit-messwiederholung.html.
22.Meissner W, Weiss T, Trippe RH, Hecht H, Krapp C, Miltner WH. Acupuncture decreases somatosensory evoked potential amplitudes to noxious stimuli in anesthetized volunteers. Anesth Analg. 2004;98(1): 141–7. 10.1213/01.ane.0000096191.07929.44 [DOI] [PubMed] [Google Scholar]
23.Bromm B, Meier W. The intracutaneous stimulus: a new pain model for algesimetric studies. Methods Find Exp Clin Pharmacol. 1984;6(7): 405–10. [PubMed] [Google Scholar]
24.Ritter A, Franz M, Dietrich C, Miltner W, Weiss T. Human brain stem structures respond differentially to noxious heat. Front Hum Neurosci. 2013;7. 10.3389/fnhum.2013.00530 [DOI] [PMC free article] [PubMed] [Google Scholar]
25.Ellermeier W, Westphal W, Heidenfelder M. On the "absoluteness" of category and magnitude scales of pain. Percept Psychophys. 1991;49(2): 159–66. 10.3758/bf03205035 [DOI] [PubMed] [Google Scholar]
26.Bradley MM, Lang PJ. Measuring emotion: The self-assessment manikin and the semantic differential. J Behav Ther Exp Psychiatry. 1994;25(1): 49–59. 10.1016/0005-7916(94)90063-9 [DOI] [PubMed] [Google Scholar]
27.Wiech K. Deconstructing the sensation of pain: The influence of cognitive processes on pain perception. Science. 2016;354: 584–7. 10.1126/science.aaf8934 [DOI] [PubMed] [Google Scholar]
28.Strobel A. Eine deutschsprachige Version des BIS/BAS-Fragebogens von Carver und White. Zeitschrift für differentielle und diagnostische Psychologie. 2001;22(3): 216–27. [Google Scholar]
29.Jensen MP, Tan G, Chua SM. Pain Intensity, Headache Frequency, and the Behavioral Activation and Inhibition Systems. Clin J Pain. 2015;31(12): 1068–74. 10.1097/AJP.0000000000000215 [DOI] [PubMed] [Google Scholar]
30.Serrano-Ibáñez ER, Ramírez-Maestre C, López-Martínez AE, Esteve R, Ruiz-Párraga GT, Jensen MP. Behavioral Inhibition and Activation Systems, and Emotional Regulation in Individuals With Chronic Musculoskeletal Pain. Front Psychiatry. 2018;9(394). [DOI] [PMC free article] [PubMed] [Google Scholar]
31.Xiang Y, Wang Y, Gao S, Zhang X, Cui R. Neural Mechanisms With Respect to Different Paradigms and Relevant Regulatory Factors in Empathy for Pain. Front Neurosci. 2018;12(507). 10.3389/fnins.2018.00507 [DOI] [PMC free article] [PubMed] [Google Scholar]
32.Davis MH. Measuring individual differences in empathy: Evidence for a multidimensional approach. J Pers Soc Psychol. 1983;44(1): 113–26. [Google Scholar]
33.McCracken LM, Dhingra L. A Short Version of the Pain Anxiety Symptoms Scale (PASS-20): Preliminary Development and Validity. Pain Res Manag. 2002;7(1): 45–50. 10.1155/2002/517163 [DOI] [PubMed] [Google Scholar]
34.Sullivan MJL. The Pain Catastrophizing Scale: Development and validation. Psychol Assess. 1995;7(4): 524–32. [Google Scholar]
35.Wentura D, Rothermund K. Priming is not Priming is not Priming. Soc Cogn. 2014;32(Supplement): 47–67. [Google Scholar]
36.Maier C, Baron R, Tölle TR, Binder A, Birbaumer N, Birklein F, et al. Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Somatosensory abnormalities in 1236 patients with different neuropathic pain syndromes. Pain. 2010;150(3): 439–450. 10.1016/j.pain.2010.05.002 [DOI] [PubMed] [Google Scholar]
37.Pfau DB, Krumova EK, Treede R-D, Baron R, Toelle T et al. Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Reference data for the trunk and application in patients with chronic postherpetic neuralgia. Pain. 2014; 155:1002–1015. 10.1016/j.pain.2014.02.004 [DOI] [PubMed] [Google Scholar]
38.Lumley MA, Cohen JL, Borszcz GS, Cano A, Radcliffe AM et al. Pain and Emotion: A biopsychsocial review of recent research. J Clin Psychol. 2011; 67: 942–968. 10.1002/jclp.20816 [DOI] [PMC free article] [PubMed] [Google Scholar]
39.Becker S, Moscovitch M, Behrmann M, Joordens S. Long-term semantic priming: a computational account and empirical evidence. J Exp Psychol: Learn Mem Cogn. 1997; 23: 1059–1082. [PubMed] [Google Scholar]
40.Weiss T, Miltner WHR, Dillmann J. The influence of semantic priming on event-related potentials to painful laser stimuli in migrane patients. Neurosci Lett. 2003; 340:135–138. 10.1016/s0304-3940(03)00103-4 [DOI] [PubMed] [Google Scholar]
41.Richter M, Weiss T. Der Einfluss von Schmerzwörtern auf die Schmerzwahrnehmung [Influence of pain-related words on pain perception.] Schmerzpatient. 2018; 1:168–175. [Google Scholar]
42.Friston KJ. A theory of cortical responses. Phil Trans Royal Soc B Biol Sci. 2005; 360: 815–836. 10.1098/rstb.2005.1622 [DOI] [PMC free article] [PubMed] [Google Scholar]
43.Friston KJ. Does predictive coding have a future? Nat. Neurosci. 2018; 21: 1019–1021. 10.1038/s41593-018-0200-7 [DOI] [PubMed] [Google Scholar]
44.Friston KJ. Waves of prediction. PLOS Biol. 2019. 10.1371/journal.pbio.3000426. [DOI] [PMC free article] [PubMed] [Google Scholar]
45.Imbir KK. Affective norms for 4900 Polish word reload (ANPW_R): Assessments for valence, arousal, dominance, origin, significance, concretness, imageability, and age of acquisition. Front Psychol. 2016; 7. 10.3389/fpsyg.2016.01081. [DOI] [PMC free article] [PubMed] [Google Scholar]
46.Pérez MA. Age of acquisition persists as a main factor in picture naming when cumulative word frequency and frequency trajectory are controlled. Quart J Exp Psychol. 2011; 60: 32–42. [DOI] [PubMed] [Google Scholar]
47.Stadthagen-Gonzalez H, Imbault C., Pérez Sánchez MA, Brybaert M. Norms of valence and arousal for 14,031 Spanish words. Behav Res Meth. 2017; 49: 111–123. 10.3758/s13428-015-0700-2 [DOI] [PubMed] [Google Scholar]
48.Warriner AB, Kuperman V, Brysbaert M. Norms of valence, arousal, and dominance for 13,915 English lemmas. Behav Res Meth. 2013; 45: 1191–1207. [DOI] [PubMed] [Google Scholar]
49.Birchenough JM, Davies R, Connelly V. Rated age-of-acquisition norms for over 3,200 German words. Behav Res Meth. 2017; 49: 484–501. 10.3758/s13428-016-0718-0 [DOI] [PubMed] [Google Scholar]

PLoS One. doi: 10.1371/journal.pone.0248744.r001

Decision Letter 0

José A Hinojosa

20 Oct 2020

PONE-D-20-29181

Influence of acute pain on valence rating of words

PLOS ONE

Dear Dr. Weiss,

Thank you for submitting your manuscript to PLOS ONE. Two expert reviewers have now provided comments about your manuscript. While both reviewers had positive words about your study, they also raised several issues that i would like that you consider in a revised version of your work. After my own reading of the manuscript, i would like that you pay particular attention to the lack of description of the motivational priming theory and the possible age of acquisition confound. Also, i encourage the authors to share the stimulus materials used in their study.

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Reviewer #1: Review of the manuscript PONE-D-20-29181titled ‘Influence of acute pain on valence rating of words’

The present work analyzes how painful primes can influence the valence of semantic stimuli. In two experiments, participants were asked to rate the valence of different semantic stimuli (pain-related, negative, positive, and neutral adjectives) after they were primed with aversive electrical stimuli. The results showed that valence ratings of pain-related, negative, and positive words were more negative after the electrical prime. This priming effect continued even some minutes after the prime ends.

1. General comments and overall evaluation

Although the study is in general well done, it needs to be improved before publication. First, the general structure with combining sections of experiment 1 and 2, and not presenting them in separate blocks, is sometimes confusing and makes the main plot of the paper makes hard to follow. More importantly, there are some critical methodological and theoretical aspects in which the current version of the paper requires further consideration and need to be revised.

On the other hand, I think the paper is well written although I am not native speaker of English.

2. Detailed review of the different sections of the paper

Introduction

Lines 39-40. I encourage to the authors to extend the description of the motivational priming theory, which is now described only in a sentence.

The effects described in the lines 41-43 would be better understood with some examples of prime-target pairs.

Material and methods

Subjects

I only suggest the use of the term “participants” to title this section. The participant description is well done.

Pain stimuli

Pain stimuli and its calibration are clearly described.

Study design

This section is a mix of “word stimuli” and “procedure”, which I think can be confusing for the reader, so I would recommend to make separate sections for materials (words and pain stimuli), instruments (scales and current stimulator descriptions), and for procedure (task events and instructions to participants), by each experiment.

The word set is not presented as appendix or in any separate file. I understand that the authors will present the stimuli if the paper is accepted for publication as the they have committed to make all data available.

Regarding the controls on the used materials (words), I strongly miss the AoA (age of acquisition) as a matching variable. There is since some years enough evidence to consider AoA of words as important as other variables like word frequency or length in word recognition and naming tasks, among others, and critically, a statistically significant, negative correlation between AoA and valence (i.e., positive words tend to be early-acquired in life) has been consistently reported in many norms studies (e.g., Imbir, 2016; Stadthagen-Gonzalez, 2017; Warriner et al., 2013). Note that the correlation is moderate (around -.2), but it is overall higher than the correlation between lexical frequency and valence. Therefore, AoA should empirically be more relevant than frequency in the word selection of studies about emotional valence. So, I am afraid that the authors should discard a confound effect because of the possible differences in AoA between word categories in both experiments. They can collect AoA data from previous databases (Birchenough, Davies, & Connelly, 2017) or collect new AoA ratings if needed, and then compare the mean AoA of words across word categories (pain-related, negative, etc.).

Each word was presented ten times to each participant in exp.1 and I understand that some times more in exp.2, so an order effect is expected in each experiment. The words preceded by pain primes were likely negatively conditioned and therefore they can be more negative rated in subsequent trials. This potential order effect should be discarded by including trial repetition as a factor (or covariable) in the analysis.

Measures in Experiment 2.

Here one run into a number of measures by questionnaires that are not mentioned until this section. I think that the rationale of these measures in relation with the objectives of the study should be commented in the introduction.

Data analyses

I think this section should go in results. Apart of that, I think that some descriptive statistics or plots (histograms, density plots, etc.) about the dependent variables’ distribution should be reported in each experiment in order to see if there is a normal distribution. This should also be done for the scores obtained in scales used in the exp.2 as. Alternatively (or additionally), the authors could perform normality tests in the results section.

Results

All performed analyses are by participants and, having into account that there few items (10) in each category of words, I strongly recommend to carry out an analysis by items in order to know if the effects are generalizable to the rest of words with similar characteristics.

Experiment 1

All t values (and df) in each post-hoc test, statistically significant or not, should be reported and, when necessary, Bonferroni corrections should be applied.

The ANOVA on the number of recalled words by word category shows differences between some categories, but this does not mean a direct relation with the priming effect. I mean that the differences can be attributed to the word characteristics themselves as other uncontrolled but relevant variables (like AoA or imageability) might be affecting the performance of this task. This is mentioned in the limitations section with a succinct sentence “This might hint a selective memory effect” and maybe it can be expanded.

Experiment 2

Same comments about t values and Bonferroni corrections as in the experiment 1.

ANOVA should be changed by ANCOVA (line 259)

Additionally, there are some considerations about the covariates. First, “sex” was not announced to be a covariate until here, at line 272. If the authors want to control the sex (or gender) of participants, first they have to explain why, and second I consider that it is more correct to including this variable as a dummy factor to adjust the degrees of freedom of the rest of contrasts than treat it as a covariate (although this is not formally incorrect). On the other hand, the non-significant effects of any covariate seem to be surprising because it was supposed they were moderating valence ratings. Moreover, I wonder if the covariates actually make a contribution in the model. In other words, ¿would do we get the same results without the covariates? If the ANOVA (without covariates) shows different results of those from the performed ANCOVA, it is possible to conclude that the covariates actually matter because they have an effect, but this was not strong enough to be detected in this experiment. All this should be reviewed and discussed by the authors

The t values of the post hoc comparison for Block (lines 262-263) should be revised because all of them are positive and I think that there should be positive and negative values if the order of contrasted levels of Block indicate the mean differences.

Discussion

In general, I expected a more theoretical discussion about implications of the effects.

Experiment 1

It should be interesting to discuss in a deeper way the implications of the results under the motivational priming and the neural networks theories and, if possible, with a specification of the cognitive mechanisms involved in the priming effects found.

The explanation that the incongruency generated by the pairs painful stimulation-positive words might be the cause of the higher priming effect on valence ratings of this type of words compared to the other categories is speculative (the authors only cite a study about the N400 that has a very indirect relationship with the present study) and partial. The authors should explain why neutral words do not generate an incongruency when primed by painful stimulation. I do not mean that neutral words should generate an incongruency in the same magnitude than positive words, but why authors assume that neutral words do not generate incongruency at all.

Experiment 2

The sentence regarding that only trials without painful stimulation were used in the analyses (lines 311-312) would go better in results than here

Text in parenthesis at line 314 should go in procedure.

The authors re-describe the results but not explain why negative priming affected valence ratings for some minutes after the end of priming.

Limitations

The paragraph from lines 345 to 355 fits better in the discussion than here.

Typing mistakes:

Line 130, “á” >> of

Used references

Birchenough, J. M., Davies, R., & Connelly, V. (2017). Rated age-of-acquisition norms for over 3,200 German words. Behavior research methods, 49(2), 484-501.

Imbir, K. K. (2016). Affective Norms for 4900 Polish Words Reload (ANPW_R): Assessments for Valence, Arousal, Dominance, Origin, Significance, Concreteness, Imageability and, Age of Acquisition. Frontiers in Psychology, 7. https://doi.org/10.3389/fpsyg.2016.01081

Stadthagen-Gonzalez, H., Imbault, C., Pérez Sánchez, M. A., & Brysbaert, M. (2017). Norms of valence and arousal for 14,031 Spanish words. Behavior Research Methods, 49(1), 111-123. https://doi.org/10.3758/s13428-015-0700-2

Warriner, A. B., Kuperman, V., & Brysbaert, M. (2013). Norms of valence, arousal, and dominance for 13,915 English lemmas. Behavior Research Methods, 45(4), 1191-1207. https://doi.org/10.3758/s13428-012-0314-x

Reviewer #2: The present manuscript of Brodhum et al. investigates the influence of painful primes on the perception of the valence of subsequent semantic stimuli by two experiments. The first one, explored the existence of the effect of this influence, and second one, focused on the length of the effect. The behavioral data indicate more negative valence ratings of the emotional words (pain-related, negative and positive) after painful prime in contrast to no prime. In addition, the effect continued some minutes after the painful prime. This is a potentially interesting study since it addresses a topic that has not been studied enough up to date. Thus, while the overall research question is within the scope of PLOS ONE readers, some aspects should be need to be improved.

-The introduction section is clear and concise. However, despite using positive words in the experiments, are not information about this kind of stimuli, and how the motivational priming theory explains its possible effects. Actually, this theory indicated two opposite responses for positive versus negative stimuli. This information its important, not only to explain the use of positive words in this study. Also, because of the subsequent results that to some extent contradict the theory.

In addition, since the authors want to explore the duration of the effect, should be include previous information about this point. Or, if there are not previous evidence, indicate it.

On the other hand, since several tests were applied to evaluate different variables that could be mediating the results, it is necessary to indicate in this section how these variables can modify the effect studied.

- In the Method section, authors did not mention any method used for the calculation of the sample size. Where there a priori power analyses to support adequate power for statistical analyses?

Additionally, since working with words it is useful to know the educational level of the subjects.

Please include examples of the different selective adjectives. Positive words were balance in arousal to negative words? Please give some explanation about this aspect.

In the experiment 2, please, include the scale used to measure the valence. There are not information about the duration of the each block and the duration of the length of the interval between the blocks.

Please include the duration of the recording session and where were conducted.

Questionnaires: authors did not indicate why is important or the relation between all the tests and the variables studied. In addition, should be include a more developed explanation of the constitution of each scale used.

-In the Discussion section:

The authors indicate that the results in experiment 1 are in line with the motivational priming theory, however, as I indicated earlier, this theory considers opposite effects for negative and positive stimuli. If the negative prime (painful stimulation) has an effect in the valence of the words, why are not influence in neutral words but if the positive?

In addition, not all results are discuses, like why positive words were evaluated so much more negatively than negative ones? The motivational priming hypothesis indicates that in a negative context, the negative is exacerbated. In line with this, negative word under painful condition should be evaluate as more negative. However, the opposite effect was observed, where negative words are evaluated less negatively.

Furthermore, suddenly, a study with PER is briefly described to try to explain the effect observed in the positive words. However, the explanation is unclear and departs from the methodology used. Should we have an N400 for this task? What process would be reflecting here?

At the end of the first study, the authors indicated that not finding differences between words related to pain and negative ones was expected. However, this contradicts what was previously stated in the introduction section, lines 58 to 60.

In the case of experiment 2, there are not a discussion, just an explanation of the results. This part should be improved.

**********

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Reviewer #1: Yes: Miguel Á. Pérez-Sánchez

Reviewer #2: No

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PLoS One. 2021 Mar 18;16(3):e0248744. doi: 10.1371/journal.pone.0248744.r002

Author response to Decision Letter 0

28 Dec 2020

Responses to Journal Requirements and Reviewers

We thank the reviewers for taking time and investing effort to provide their constructive comments to improve the manuscript (Ms). We have addressed all the comments in a point-by-point reply. Our answers are indicated in blue font below. We provide a marked-up copy of our manuscript highlighting changes made in the original version as well as an unmarked version of the revised manuscript. We report places of changes in this letter with respect to the marked-up copy of Ms.

Journal Requirements

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

Answer: We followed this advice.

Answer: We thank for this advice. We give now additional information in the ethical statement and the MS, as requested.

Answer: We will make available all data at acceptance. Please note that we provide already substantial part of the data in the supplementary material.

Reviewer 1

1. General comments and overall evaluation

Answer: We thank for this advice. In accordance with your suggestion, we changed the order by binding into separate blocks each of the two experiments. So, we hope that the Ms is easier to follow now.

… More importantly, there are some critical methodological and theoretical aspects in which the current version of the paper requires further consideration and need to be revised.

On the other hand, I think the paper is well written although I am not native speaker of English.

The details of the criticism of the reviewer are explained in the second part of review so that we will answer to each point in part two.

2. Detailed review of the different sections of the paper

Introduction

Lines 39-40. I encourage to the authors to extend the description of the motivational priming theory, which is now described only in a sentence.

Answer: We added some more information concerning motivational priming theory (in accordance with the reviewer’s suggestion, now lines 39-46).

The effects described in the lines 41-43 would be better understood with some examples of prime-target pairs.

Answer: We thank for this advice. In accordance with your suggestion, we included examples of the primes (now lines 49-54).

Material and methods

Subjects

I only suggest the use of the term “participants” to title this section. The participant description is well done.

Answer: We followed this advice (line 87).

Pain stimuli

Pain stimuli and its calibration are clearly described.

Thank you.

Study design

Answer: We reorganized the structure with respect to several aspects: First, we organized the middle of the Ms (Methods, Results) according to suggestions at general comments, i.e. first Exp. 1, second Exp. 2. Within the description of the experiments, we tried to follow the proposal made here, i.e. with separate sections for Word stimuli and Study design.

Answer: As we understand, the reviewer requests the stimulus material (instead of pointing to this information as in the references). We now gave examples of words in the text and show the stimulus material (word set) in the supporting information together with the major results (Supplementary table S1: Valence ratings (mean ± SD) of each word in the main experiment.).

Answer: Thank you for this advice. To be honest, we were not aware of this factor. Unfortunately, the German database does not include our adjectives, so that we were not able to compare this aspect for our stimulus material. We believe that an additional examination for AoA would overburden us and overcharge the Ms. Moreover, as we understand, the differences are mainly between positively vs. negatively valanced words. Therefore, AoA is quite plausible for explaining differences in priming effects between positive and negative valanced words. We included this important point to the discussion of the effect of positive adjectives (lines 650-657). Moreover, we included it as an unexplained factor to the limitation section (687-703).

Answer: Thank you very much for mentioning this important point. While we do not think that conditioning plays an important role (as each of the words is presented in 50% of trials with and in 50% of trials without preceding pain stimulation), repetitions might play a role. Therefore, we now included an additional within-subject factor Repetition to the ANOVA. While Repetition is relevant for the data, the main results with respect to our theoretical framework are not changed by this additional factor. We now show the results including factor Repetition (lines 255ff).

Measures in Experiment 2.

Answer: We apologize for not making the sense of including questionnaires to Exp. 2 clear.

The questionnaires were included as the different characteristics examined with the questionnaires are known to possibly influence on pain ratings. After having found the principle correctness of our primary hypotheses in Exp. 1, the primary aim of including these questionnaires to Exp. 2 was to control for possible influences on our results. We explained this now in more detail in the description of experiment 2 (lines 418ff).

Data analyses

Answer: According to the recommendations to reorganize the structure, we moved the section data analysis to each experiment. We also included the mentioning of tests for normality of data (before ANOVA or ANCOVA). This is now included to the Ms (lines 245ff). However, we believe that the description of the statistical analyses belongs to the method section. We organized it in such a way that it directly precedes the result section in order to not repeat this content several times.

Results

Answer: We followed the advice and included an additional factor (Repetition) to the analysis. We also provide a supplementary table with each item including its characteristics. However, we remained with Word categories as this was our major research interest. Moreover, our main research questions and hypotheses belong to the Word categories.

Experiment 1

All t values (and df) in each post-hoc test, statistically significant or not, should be reported and, when necessary, Bonferroni corrections should be applied.

Answer: According to advice, we included now all statistical values (throughout the MS).

Answer: As described earlier, we included now AoA to the discussion of priming effects on positive adjectives. Additionally, we included this possible effect as requested and possible other effects (abstractness, imageability) to the limitation section (lines 690ff). We also added an expansion of the selective memory effect as requested (lines 701f).

Experiment 2

Same comments about t values and Bonferroni corrections as in the experiment 1.

Answer: According to advice, we included now all statistical values (throughout the ms).

ANOVA should be changed by ANCOVA (line 259)

Answer: We changed this accordingly.

Answer: We apologize for this mistake. Gender was included as it is known to possibly influence on pain ratings. We explained this in detail (lines 418ff, 547ff).

Answer: We are sorry, we reported the absolute values of the t-values. We corrected this mistake (throughout the MS).

Discussion

In general, I expected a more theoretical discussion about implications of the effects.

Answer: We added more discussion on implications now (e.g., lines 588ff). Details are specified below.

Experiment 1

Answer: We provide now a deeper discussion on both theories. We tried to realize a specification with respect to some cognitive mechanisms (lines 593ff). In case, this reviewer has different aspects in mind, we will be happy to include these after receiving a little help for this.

Answer: We agree. We tried to integrate this point with respect to the theory on predictive coding (lines 662-673). From this point of view, there is less prediction error with respect to evoked valence for a following painful stimulus in a plausible order from pain-related to negative to neutral to positive adjectives. In contrast, this prediction error is different for the trials without a following painful stimulus. Here, the discrepancy is minimal for neutral adjectives and similar for the other types of adjectives as they all have the same valence. In any case, a prediction error will lead to an activation of salience and to actualization of expectations. This results in larger cognitive load which might have effects on the valence ratings and the perception of pain. As a result (but highly speculative and not included to the MS), there might be counteracting activity for network priming vs. prediction errors. We included this into the general discussion section (lines 639-657).

Experiment 2

The sentence regarding that only trials without painful stimulation were used in the analyses (lines 311-312) would go better in results than here

Answer: This sentence was misleading. On the one hand, we analyzed the both trials with and without painful stimulation in Experiment 2. On the other hand, we assessed aftereffects of the painful stimulation (i.e. one of the major goals of Exp. 2), we analyzed specifically all trials without a following painful stimulation. It turns out that the overall valence ratings are more negative in the post-block 1 compared to baseline, while returning to baseline in post-block 2. Obviously, we need the sentence to clarify the selection of trials for this specific analysis at this point, so we cannot remove it from this part of text. However, we tried to make this point of selection of this specific analysis clearer now (lines 527-542).

Text in parenthesis at line 314 should go in procedure.

Answer: We moved this text to procedure as suggested (now end of §2 in the description of Exp. 2).

The authors re-describe the results but not explain why negative priming affected valence ratings for some minutes after the end of priming.

Answer: We formulated our explanation with respect to long-term priming in more detail (now lines 559ff).

Limitations

The paragraph from lines 345 to 355 fits better in the discussion than here.

Answer: We fully agree, thanks for this advice. We move this part to the discussion section.

Typing mistakes:

Line 130, “á” >> of

Answer: Thanks for careful reading. We changed it.

Used references

Birchenough, J. M., Davies, R., & Connelly, V. (2017). Rated age-of-acquisition norms for over 3,200 German words. Behavior research methods, 49(2), 484-501.

Answer: Thank you. We included those references to the discussion.

Reviewer 2

The present manuscript of Brodhum et al. investigates the influence of painful primes on the perception of the valence of subsequent semantic stimuli by two experiments. The first one, explored the existence of the effect of this influence, and second one, focused on the length of the effect. The behavioral data indicate more negative valence ratings of the emotional words (pain-related, negative and positive) after painful prime in contrast to no prime. In addition, the effect continued some minutes after the painful prime. This is a potentially interesting study since it addresses a topic that has not been studied enough up to date. Thus, while the overall research question is within the scope of PLOS ONE readers, ….

Answer: Thank you for this kind assessment.

… some aspects should be need to be improved.

Answer: We now included a more extensive description of the motivational priming theory as well as predictions from this theory with respect to our categories of adjectives (lines 39-54).

In addition, since the authors want to explore the duration of the effect, should be include previous information about this point. Or, if there are not previous evidence, indicate it.

Answer: We also added information on the duration that we were able to identify (line 82f).

Answer: We describe the variables now in the participants section as these variables are rather known to influence pain perception. We thought that the description is clearer at this place (now lines **) than in the intro, as it is rather to control other influences than to develop the theoretical point of view and/or aims and hypotheses for this study.

- In the Method section, authors did not mention any method used for the calculation of the sample size. Where there a priori power analyses to support adequate power for statistical analyses?

Answer: We used a tool for our a priori analyses (Hemmerich, W. (2020). StatistikGuru: Stichprobengröße für die ANOVA mit Messwiederholung berechnen. Retrieved from https://statistikguru.de/rechner/stichprobengroesse-anova-mit-messwiederholung.html). Considering the fact that there are no studies investigating the effect of painful priming on the valence of words, we used previous results of our research group investigating the effect of affective priming on pain ratings as a starting point. Considering the number of measurements for each person we calculated a necessary sample size of approximately 20 participants with α = 0.05 and power = 0.9 (lines 103-109).

Additionally, since working with words it is useful to know the educational level of the subjects.

Answer: All subjects were university students. We added this information in lines 84/85.

Please include examples of the different selective adjectives. Positive words were balance in arousal to negative words? Please give some explanation about this aspect.

Answer: We included an example for each word to the text (lines 152f). Moreover, we added information to the verbal material and the type of matching (lines 154ff). Finally, all used adjectives (together with their results) as well as the original data are now in the Supporting information.

In the experiment 2, please, include the scale used to measure the valence.

Answer: We used the same scales as in experiment 1 (Fig 1). We added this information in line 401.

There are not information about the duration of the each block and the duration of the length of the interval between the blocks.

Please include the duration of the recording session and where were conducted.

Answer: We included this information (Study design of Exp. 1 and 2, first §).

Answer: We included more information on the Questionnaires. The major reason to use them was to exclude possible influences on the results. Each of the examined variables has previously shown to possibly influence on pain ratings.

We now included more information to make this point clear (418-427).

-In the Discussion section:

Answer: We were not precise enough in our previous version. We now tried to give the pieces of results which are in accordance with the motivational priming theory more precisely (lines 338-344, 588-592).

Answer: We fully agree. We had not presented a plausible discussion to positive adjectives. This has the reason that this was not our primary goal. We now tried to give a background for this difference (lines 636-657).

Answer: We think that the argument of disagreement between expectation and occurrence of unexpected content is still valid. However, the study with N400 is far away and requires extensive explanation. As we now explain this point using the theory of predictive coding, we decided to remove this part of MS.

Answer: We were not precise enough. There are different predictions with respect to emotional priming theory and network theory. We tried to clarify this throughout the MS.

In the case of experiment 2, there are not a discussion, just an explanation of the results. This part should be improved.

Answer: We changed and extended the discussion to Exp. 2 (lines 553-580).

Attachment

Submitted filename: Response to Reviewers_2020-12-23.docx

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PLoS One. doi: 10.1371/journal.pone.0248744.r003

Decision Letter 1

José A Hinojosa

1 Feb 2021

PONE-D-20-29181R1

Influence of acute pain on valence rating of words

PLOS ONE

Dear Dr. Weiss,

Thank you for submitting your manuscript to PLOS ONE. I have received feedback from the two original reviewers. One of them recommended acceptance (pending some very minor changes). The other reviewer still have some concerns, mainly regarding the age of acquisition of the words, that should be addressed before publication. Please, try your best with the new version of the revised manuscript as i would like to make a final decision.

Please submit your revised manuscript by Mar 18 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

We look forward to receiving your revised manuscript.

Kind regards,

José A Hinojosa, Ph.D.

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Partly

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Reviewer #1: The manuscript has been properly improved in many ways: a clearer rationale, the experimental procedure has been better described, a more informative data analysis and results, and the discussion goes more in-depth into the cognitive mechanisms that may be explaining the results.

However, I am afraid that I still cannot recommend the current version for publication because the two main concerns I raised in the first review have not been addressed.

First, the AoA of words is still unknown. If there were no AoA scores from previous studies for the words used in the experiments, the authors could have collected them through a rating study, which should not have been complicated given the low number of items to rate. In that case, if the mean AoA scores were similar by categories a possible confounding effect due to AoA of words would have been discarded; if the AoA scores were not similar by categories the speculation about a possible effect of AoA could have been state more exactly and based on data. In any case, I consider that including the omission of AoA scores as a limitation is an easy and not a sufficient solution.

On the other hand, a by-item analysis has not been carried out as I encouraged to perform. Without it we cannot rule out that the results are due to a few items that generate a strong effect. In other words, the effects are not generalizable to other (similar) words.

Reviewer #2: The manuscript has improved a lot by the changes made since the first submission. The authors have taken into account all comments and have responded appropriately to them. I would only like to suggest a few things:

In results section: when talking about significant differences found, it is convenient to always indicate in which direction these differences go in the text. Even though there is a figure or the means, it is useful that also indicated in the text. Like in lines 223, 264.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Miguel Á. Pérez-Sánchez

Reviewer #2: Yes: Irene Peláez Cordeiro

PLoS One. 2021 Mar 18;16(3):e0248744. doi: 10.1371/journal.pone.0248744.r004

Author response to Decision Letter 1

2 Mar 2021

Responses to Journal Requirements and Reviewers

We thank the reviewers for taking time and effort to provide their constructive comments to improve the manuscript (Ms). We have addressed all the comments in a point-by-point reply. Our answers are indicated in blue font below. We provide a revised manuscript with track changes as well as an unmarked version of the revised manuscript. We report places of changes in this letter with respect to the marked-up copy of Ms.

Reviewer 1

The manuscript has been properly improved in many ways: a clearer rationale, the experimental procedure has been better described, a more informative data analysis and results, and the discussion goes more in-depth into the cognitive mechanisms that may be explaining the results.

Thank you.

However, I am afraid that I still cannot recommend the current version for publication because the two main concerns I raised in the first review have not been addressed. First, the AoA of words is still unknown. If there were no AoA scores from previous studies for the words used in the experiments, the authors could have collected them through a rating study, which should not have been complicated given the low number of items to rate. In that case, if the mean AoA scores were similar by categories a possible confounding effect due to AoA of words would have been discarded; if the AoA scores were not similar by categories the speculation about a possible effect of AoA could have been state more exactly and based on data. In any case, I consider that including the omission of AoA scores as a limitation is an easy and not a sufficient solution.

Answer:

We followed your advice and conducted a small rating study for the words used in our experiments to explore the AoA. Unfortunately, there is no German database containing the AoA of our adjectives. Birchenough, Davies, & Connelly (2017) delivered norms for over 3,200 German words, but only investigated the AoA of nouns and verbs. We used the same instructions and questionnaire as Birchenough, Davies, & Connelly (2017). We found similar mean AoA scores by categories. Details to this rating study are given in the Overall Discussion (lines 515-525). Furthermore, we adjusted the parts concerning AoA in Limitation and future directions (lines 546-558).

In addition, we searched the AoA norm by Birchenough, Davies, & Connelly (2017) for words similar to the ones we used in our study (with similar word stem) and found similar means to our rating study:

Birchenough, Davies, & Connelly (2017) our rating study

word Mean AoA word Mean AoA

Schimmel 5.9 schimmlig 6.0

stinken 3.6 stinkend 3.7

Dreck 4.0 verdreckt 3.3

gehen 2.9 gehend 2.8

blond 4.6 aschblond 4.4

Himmel 3.2 himmlisch 3.4

Zauber 5.5 bezaubernd 4.5

Answer:

We followed the advice and ran the analyses by item. We found a main effect for the factor Word and an interaction effect Category*Word. Post-hoc tests are presented in Table S2 in the supporting information. It seems that the words in the positive and neutral categories are rated more homogeneously concerning their overall valence in contrast to the pain-related and negative categories. However, we found no significant interaction between the factors Word and Prime. This indicates that the effect of the factors Prime and Category on valence ratings are not just due to a few items generating a strong effect. It rather shows a more general effect not just of individual words, but of word categories. We adjusted the affected parts in the Results and Discussion sections (lines 201/202, 212-217, 234-237, 317-320, 376, 391-398).

Reviewer 2

The manuscript has improved a lot by the changes made since the first submission. The authors have taken into account all comments and have responded appropriately to them. I would only like to suggest a few things: In results section: when talking about significant differences found, it is convenient to always indicate in which direction these differences go in the text. Even though there is a figure or the means, it is useful that also indicated in the text. Like in lines 223, 264.

Answer:

We thank you for this advice. In accordance with your suggestion, we adjusted the results sections (lines 223/224, 228/229, 252-257, 272/273, 286, 406, 408, 415).

Attachment

Submitted filename: Response to Reviewers_2021-03-02_Th.docx

Click here for additional data file.^{(18.8KB, docx)}

PLoS One. doi: 10.1371/journal.pone.0248744.r005

Decision Letter 2

José A Hinojosa

5 Mar 2021

Influence of acute pain on valence rating of words

PONE-D-20-29181R2

Dear Dr. Weiss,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Reviewer #1: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

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6. Review Comments to the Author

Reviewer #1: The authors have considered all comments and have responded acceptably to them.

On the one hand, once the AoA of the words has been obtained, it does not seem to be a confounding effect due to that variable.

On the other hand, although the requested “item analysis” has not been performed in the standard way (i.e., considering items as the random factor), I think that a non-significant interaction between prime and word contributes to discard that the priming effects on valence ratings are not just due to a few items. BUT, I would only like to suggest that the result for the three-way interaction category*prime*word should be reported in order to remove any doubt about the effect of items on the critical interaction category*prime.

**********

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Reviewer #1: Yes: Miguel Á. Pérez-Sánchez

PLoS One. doi: 10.1371/journal.pone.0248744.r006

Acceptance letter

José A Hinojosa

9 Mar 2021

PONE-D-20-29181R2

Influence of acute pain on valence rating of words

Dear Dr. Weiss:

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on behalf of

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

S1 Table. Valence ratings (mean ± SD) of each word in the main experiment.

(PDF)

Click here for additional data file.^{(55.5KB, pdf)}

S2 Table. Corrected p-values for contrasts regarding interaction effect Category*Word in the main experiment.

(PDF)

Click here for additional data file.^{(46.8KB, pdf)}

Attachment

Submitted filename: Response to Reviewers_2020-12-23.docx

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Attachment

Submitted filename: Response to Reviewers_2021-03-02_Th.docx

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Data Availability Statement

All data are given in the Ms and the Supplementary material.

[pone.0248744.ref001] 1.Arnold BS, Alpers GW, Suss H, Friedel E, Kosmutzky G, Geier A, et al. Affective pain modulation in fibromyalgia, somatoform pain disorder, back pain, and healthy controls. Eur J Pain. 2008;12(3): 329–38. 10.1016/j.ejpain.2007.06.007 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref002] 2.Rhudy JL, Williams AE, McCabe KM, Russell JL, Maynard LJ. Emotional control of nociceptive reactions (ECON): Do affective valence and arousal play a role? Pain. 2008;136(3): 250–61. 10.1016/j.pain.2007.06.031 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref003] 3.Kenntner-Mabiala R, Weyers P, Pauli P. Independent effects of emotion and attention on sensory and affective pain perception. Cogn Emot. 2007;21(8): 1615–29. [Google Scholar]

[pone.0248744.ref004] 4.Godinho F, Magnin M, Frot M, Perchet C, Garcia-Larrea L. Emotional Modulation of Pain: Is It the Sensation or What We Recall? J Neurosci. 2006;26(44): 11454–61. 10.1523/JNEUROSCI.2260-06.2006 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref005] 5.de Wied M, Verbaten MN. Affective pictures processing, attention, and pain tolerance. Pain. 2001;90(1–2): 163–72. 10.1016/s0304-3959(00)00400-0 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref006] 6.Weisenberg M, Raz T, Hener T. The influence of film-induced mood on pain perception. Pain. 1998;76(3): 365–75. 10.1016/S0304-3959(98)00069-4 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref007] 7.Roy M, Peretz I, Rainville P. Emotional valence contributes to music-induced analgesia. Pain. 2008;134: 140–7. 10.1016/j.pain.2007.04.003 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref008] 8.Villemure C, Slotnick BM, Bushnell MC. Effects of odors on pain perception: deciphering the roles of emotion and attention. Pain. 2003;106(1–2): 101–8. 10.1016/s0304-3959(03)00297-5 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref009] 9.Ritter A, Franz M, Miltner WHR, Weiss T. How words impact on pain. Brain Behav. 2019;9(9). 10.1002/brb3.1377 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref010] 10.Swannell ER, Brown CA, Jones AK, Brown RJ. Some Words Hurt More Than Others: Semantic Activation of Pain Concepts in Memory and Subsequent Experiences of Pain. J Pain. 2016;17(3): 336–49. 10.1016/j.jpain.2015.11.004 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref011] 11.Richter M, Schroeter C, Puensch T, Straube T, Hecht H, Ritter A, et al. Pain-related and negative semantic priming enhances perceived pain intensity. Pain Res Manag. 2014;19(2): 69–74. 10.1155/2014/425321 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref012] 12.Dillmann J, Miltner WH, Weiss T. The influence of semantic priming on event-related potentials to painful laser-heat stimuli in humans. Neurosci Lett. 2000;284(1–2): 53–56. 10.1016/s0304-3940(00)00957-5 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref013] 13.Dorjee D, Devenney L, Thierry G. Written words supersede pictures in priming semantic access: A P300 study. Neuroreport. 2010;21: 887–91. 10.1097/WNR.0b013e32833da46a [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref014] 14.Lang PJ. The emotion probe: Studies of motivation and attention. Am Psychol. 1995;50(5): 372–85. 10.1037//0003-066x.50.5.372 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref015] 15.Ogino Y, Nemoto H, Inui K, Saito S, Kakigi R, Goto F. Inner experience of pain: imagination of pain while viewing images showing painful events forms subjective pain representation in human brain. Cereb Cortex. 2007;17(5): 1139–46. 10.1093/cercor/bhl023 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref016] 16.Hebb DO. Organization of behavior. New York: Wiley; 1949. [Google Scholar]

[pone.0248744.ref017] 17.Eck J, Richter M, Straube T, Miltner WH, Weiss T. Affective brain regions are activated during the processing of pain-related words in migraine patients. Pain. 2011;152(5): 1104–13. 10.1016/j.pain.2011.01.026 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref018] 18.Richter M, Eck J, Straube T, Miltner WH, Weiss T. Do words hurt? Brain activation during the processing of pain-related words. Pain. 2010;148(2): 198–205. 10.1016/j.pain.2009.08.009 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref019] 19.Cave CB, Squire LR. Intact and long‐lasting repetition priming in amnesia. J Exp Psychol Learn Mem Cogn. 1992;18: 509–520. 10.1037//0278-7393.18.3.509 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref020] 20.Hautzinger M, Keller F, Kühner C. Beck Depressions-Inventar: BDI II. Revision. Frankfurt am Main: Harcourt Test Services; 2006. [Google Scholar]

[pone.0248744.ref021] 21.Hemmerich, W. (2020). StatistikGuru: Stichprobengröße für die ANOVA mit Messwiederholung berechnen. Retrieved from https://statistikguru.de/rechner/stichprobengroesse-anova-mit-messwiederholung.html.

[pone.0248744.ref022] 22.Meissner W, Weiss T, Trippe RH, Hecht H, Krapp C, Miltner WH. Acupuncture decreases somatosensory evoked potential amplitudes to noxious stimuli in anesthetized volunteers. Anesth Analg. 2004;98(1): 141–7. 10.1213/01.ane.0000096191.07929.44 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref023] 23.Bromm B, Meier W. The intracutaneous stimulus: a new pain model for algesimetric studies. Methods Find Exp Clin Pharmacol. 1984;6(7): 405–10. [PubMed] [Google Scholar]

[pone.0248744.ref024] 24.Ritter A, Franz M, Dietrich C, Miltner W, Weiss T. Human brain stem structures respond differentially to noxious heat. Front Hum Neurosci. 2013;7. 10.3389/fnhum.2013.00530 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref025] 25.Ellermeier W, Westphal W, Heidenfelder M. On the "absoluteness" of category and magnitude scales of pain. Percept Psychophys. 1991;49(2): 159–66. 10.3758/bf03205035 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref026] 26.Bradley MM, Lang PJ. Measuring emotion: The self-assessment manikin and the semantic differential. J Behav Ther Exp Psychiatry. 1994;25(1): 49–59. 10.1016/0005-7916(94)90063-9 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref027] 27.Wiech K. Deconstructing the sensation of pain: The influence of cognitive processes on pain perception. Science. 2016;354: 584–7. 10.1126/science.aaf8934 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref028] 28.Strobel A. Eine deutschsprachige Version des BIS/BAS-Fragebogens von Carver und White. Zeitschrift für differentielle und diagnostische Psychologie. 2001;22(3): 216–27. [Google Scholar]

[pone.0248744.ref029] 29.Jensen MP, Tan G, Chua SM. Pain Intensity, Headache Frequency, and the Behavioral Activation and Inhibition Systems. Clin J Pain. 2015;31(12): 1068–74. 10.1097/AJP.0000000000000215 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref030] 30.Serrano-Ibáñez ER, Ramírez-Maestre C, López-Martínez AE, Esteve R, Ruiz-Párraga GT, Jensen MP. Behavioral Inhibition and Activation Systems, and Emotional Regulation in Individuals With Chronic Musculoskeletal Pain. Front Psychiatry. 2018;9(394). [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref031] 31.Xiang Y, Wang Y, Gao S, Zhang X, Cui R. Neural Mechanisms With Respect to Different Paradigms and Relevant Regulatory Factors in Empathy for Pain. Front Neurosci. 2018;12(507). 10.3389/fnins.2018.00507 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref032] 32.Davis MH. Measuring individual differences in empathy: Evidence for a multidimensional approach. J Pers Soc Psychol. 1983;44(1): 113–26. [Google Scholar]

[pone.0248744.ref033] 33.McCracken LM, Dhingra L. A Short Version of the Pain Anxiety Symptoms Scale (PASS-20): Preliminary Development and Validity. Pain Res Manag. 2002;7(1): 45–50. 10.1155/2002/517163 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref034] 34.Sullivan MJL. The Pain Catastrophizing Scale: Development and validation. Psychol Assess. 1995;7(4): 524–32. [Google Scholar]

[pone.0248744.ref035] 35.Wentura D, Rothermund K. Priming is not Priming is not Priming. Soc Cogn. 2014;32(Supplement): 47–67. [Google Scholar]

[pone.0248744.ref036] 36.Maier C, Baron R, Tölle TR, Binder A, Birbaumer N, Birklein F, et al. Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Somatosensory abnormalities in 1236 patients with different neuropathic pain syndromes. Pain. 2010;150(3): 439–450. 10.1016/j.pain.2010.05.002 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref037] 37.Pfau DB, Krumova EK, Treede R-D, Baron R, Toelle T et al. Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Reference data for the trunk and application in patients with chronic postherpetic neuralgia. Pain. 2014; 155:1002–1015. 10.1016/j.pain.2014.02.004 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref038] 38.Lumley MA, Cohen JL, Borszcz GS, Cano A, Radcliffe AM et al. Pain and Emotion: A biopsychsocial review of recent research. J Clin Psychol. 2011; 67: 942–968. 10.1002/jclp.20816 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref039] 39.Becker S, Moscovitch M, Behrmann M, Joordens S. Long-term semantic priming: a computational account and empirical evidence. J Exp Psychol: Learn Mem Cogn. 1997; 23: 1059–1082. [PubMed] [Google Scholar]

[pone.0248744.ref040] 40.Weiss T, Miltner WHR, Dillmann J. The influence of semantic priming on event-related potentials to painful laser stimuli in migrane patients. Neurosci Lett. 2003; 340:135–138. 10.1016/s0304-3940(03)00103-4 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref041] 41.Richter M, Weiss T. Der Einfluss von Schmerzwörtern auf die Schmerzwahrnehmung [Influence of pain-related words on pain perception.] Schmerzpatient. 2018; 1:168–175. [Google Scholar]

[pone.0248744.ref042] 42.Friston KJ. A theory of cortical responses. Phil Trans Royal Soc B Biol Sci. 2005; 360: 815–836. 10.1098/rstb.2005.1622 [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref043] 43.Friston KJ. Does predictive coding have a future? Nat. Neurosci. 2018; 21: 1019–1021. 10.1038/s41593-018-0200-7 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref044] 44.Friston KJ. Waves of prediction. PLOS Biol. 2019. 10.1371/journal.pbio.3000426. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref045] 45.Imbir KK. Affective norms for 4900 Polish word reload (ANPW_R): Assessments for valence, arousal, dominance, origin, significance, concretness, imageability, and age of acquisition. Front Psychol. 2016; 7. 10.3389/fpsyg.2016.01081. [DOI] [PMC free article] [PubMed] [Google Scholar]

[pone.0248744.ref046] 46.Pérez MA. Age of acquisition persists as a main factor in picture naming when cumulative word frequency and frequency trajectory are controlled. Quart J Exp Psychol. 2011; 60: 32–42. [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref047] 47.Stadthagen-Gonzalez H, Imbault C., Pérez Sánchez MA, Brybaert M. Norms of valence and arousal for 14,031 Spanish words. Behav Res Meth. 2017; 49: 111–123. 10.3758/s13428-015-0700-2 [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref048] 48.Warriner AB, Kuperman V, Brysbaert M. Norms of valence, arousal, and dominance for 13,915 English lemmas. Behav Res Meth. 2013; 45: 1191–1207. [DOI] [PubMed] [Google Scholar]

[pone.0248744.ref049] 49.Birchenough JM, Davies R, Connelly V. Rated age-of-acquisition norms for over 3,200 German words. Behav Res Meth. 2017; 49: 484–501. 10.3758/s13428-016-0718-0 [DOI] [PubMed] [Google Scholar]

PERMALINK

Influence of acute pain on valence rating of words

Christoph Brodhun

Eleonora Borelli

Thomas Weiss

Roles

Abstract

Introduction

Experiment 1

Participants

Pain stimuli

Rating scale

Somatosensory perception threshold

Intensity to evoke moderately painful perceptions

Word stimuli

Study design

Structure of a trial

Fig 1. Design of the experimental trials.

Data analysis

Results of Experiment 1

Fig 2. Valence ratings with respect to the factors Prime and Category.

Fig 3. Differences in valence ratings (Δ valence ratings) with respect to the assessed words (factor Category).

Fig 4. Pain ratings with respect to the factors Prime and Category.

Discussion to Experiment 1

Experiment 2

Participants, word stimuli, study design

Measures in Experiment 2

Data analysis

Results of Experiment 2

Fig 5. Valence ratings with respect to the factor Block.

Discussion to Experiment 2

Overall discussion

Limitation and future directions

Conclusion

Supporting information

Acknowledgments

Data Availability

Funding Statement

References

Decision Letter 0

José A Hinojosa

Roles

Author response to Decision Letter 0

Decision Letter 1

José A Hinojosa

Roles

Author response to Decision Letter 1

Decision Letter 2

José A Hinojosa

Roles

Acceptance letter

José A Hinojosa

Roles

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

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