An experiment to assess emotional and physiological arousal and personality correlates while imagining deceit

Abstract

In order to examine how personality traits, emotional arousal and physiological arousal affect deception confidence, students (N = 102) completed the Eysenck Personality Questionnaire–Revised (EPQ–R) as well as stress and deception tasks while their heart rate variability was measured. Findings indicated psychoticism did not moderate how physiologically aroused participants were while viewing emotionally salient stimuli (video of a road traffic accident) or the thought of enacting deceit, although this came close to significance. However, participants (particularly males) higher in psychoticism reported less subjective distress after imagining enacting deceit than those lower on psychoticism. Extroversion had no impact on physiological arousal when viewing emotionally salient stimuli or thinking about enacting deceit. However, extroverts reported more subjective distress after thinking about enacting deceit than introverts. Also, deception confidence was not correlated to any of these variables. Future research could examine a sample higher in psychoticism and how this trait impacts deception confidence.

Introduction

Deception research has examined the ability to enact deceit with the aim of determining whether or not we are able to detect when people are being deceptive. However, a consensus as to what differentiates ept from inept deceivers has yet to be found. This is due to the multitude of factors that influence deceptive interactions, including the individual cognitive, emotional and behavioural differences of deceivers. Yet while some attempts at deception fail, others are successful (Bond & DePaulo, 2008). Thus, we see the need to understand why some deceivers are able to appear credible while others are not. Through investigating the association of physiological and psychological characteristics of individuals (i.e. extroversion/introversion, psychoticism, emotional and physiological arousal) with their confidence as deceivers, we hope to begin to determine the characteristics that impact on one’s success at dissimulation.

First, we provide definitions of deception, emotion, arousal, introversion/extroversion and psychoticism. Next, we discuss deception-related emotions and emotion management. Following this we briefly discuss the personality traits of introversion/extroversion and psychoticism as personality traits that may impact the ability to deceive. We then provide an overview of the methodology of this study.

Definitions

Deception is defined as intentionally misleading others through the act of deliberately providing, distorting or omitting information, and is usually intended to benefit the deceiver (Bond & Robinson, 1988; Podlesney & Raskin, 1977; Vendemia, Buzan, & Simon-Dack, 2005). Deception cues encompass verbal and non-verbal behaviours that suggest deception is occurring but do not reveal which part of the message is false (Ekman & Friesen, 1974). While deception cues can betray the occurrence of deception, they do not leak the concealed emotion (Ekman, 1988). Leakage refers to signs of emotion (e.g. heightened arousal and positive or negative affect) that individuals have attempted to conceal from others (Burgoon & Buller, 1994; Ekman & Friesen, 1969, 1974) in order to appear convincing while enacting deceit.

Biologically, emotion has been conceptualized as a multifaceted set of interactions within the neural and hormonal systems that can generate affective experiences, such as feelings of arousal (Kleinginna & Kleinginna, 1981). Physiological changes in response to emotionally arousing conditions may lead to adaptive or goal-directed changes in behaviour (Kleinginna & Kleinginna, 1981). Arousal refers to how calming or exciting individuals find the experience of specific emotions (Kensinger, 2004). This is important because emotional arousal can interfere with the successful production of verbal messages and non-verbal behaviours (DePaulo, Kirkendol, Tang, & O’Brien, 1988; Ekman, 1981).

Heart rate variability (HRV) refers to the variation in the time interval between heartbeats and is measured by the variation in the beat-to-beat intervals.

Extroversion is characterized by positive affect, being talkative, and prone to seeking stimulation; introversion encompasses a reserved temperament characterized by a focus on internal thoughts, feelings, and moods; and psychoticism encompasses a personality pattern typified by aggression, tough-mindedness, recklessness, and impulsivity (Eysenck & Eysenck, 1985).

Deception-related emotions and emotion management

The ability to falsify or conceal the information component of a deceptive message while simultaneously concealing any affect provoked by the information being conveyed or withheld is essential for the successful perpetration of deceit (Ekman, 1981). However, people vary in their ability to regulate deception-related emotions (e.g. guilt or detection apprehension; Bond & DePaulo, 2008). Additionally, when emotional reactions to enacting deceit are particularly strong, it is more challenging for deceivers to control their behaviour (DePaulo, 1992; Ekman, 1988). This can lead to leakage that may be incongruent with one’s behaviour or verbal message (Ekman & Friesen, 1974). Behavioural inconsistencies such as this can be an indication of deception.

Emotional expression and introversion/extroversion

Some people are naturally more spontaneously expressive than others. Thus, the degree to which felt emotions are readable from non-verbal facial expressions that individuals are not deliberately trying to convey will vary among individuals (DePaulo, 1992; DePaulo, Blank, Swaim, & Hairfield, 1992; Kring, Smith, & Neale, 1994). In addition, spontaneously expressive individuals (i.e. extroverts) are more skilled at posing emotional expressions than individuals who are not spontaneously expressive (i.e. introverts; DePaulo et al. 1992; Tucker & Riggio, 1988). When enacting deceit that does not trigger strong emotions, expressive individuals have been found to be better deceivers than unexpressive individuals (DePaulo et al. 1992). In essence, it has been argued that expressive individuals tend to appear no more deceptive when being dishonest than they do when they are being honest (DePaulo et al. 1992). This may be due to their ability to control their facial expressions to both conceal and feign emotions. Thus, while less emotionally expressive individuals (i.e. introverts) may naturally display less emotional leakage, spontaneously expressive individuals (i.e. extroverts) are better able to control emotional leakage and feign emotions. Thus, the personality trait of introversion/extroversion may influence how well people can control the display of deception-related emotions. So long as they are not experiencing strong emotions, extroverts may actually be more successful deceivers than introverts.

Emotional expression and arousal

There is a link between physiological arousal and the expression of facial displays of emotion (Buck, Miller, & Caul, 1974; Buck, Savin, Miller, & Caul, 1972). Naturally spontaneous expressers (i.e. extroverts) have been found to exhibit weaker physiological reactions (i.e. skin conductance and HR) in response to emotionally arousing situations than natural inhibitors (i.e. introverts; Buck et al., 1974; Buck et al., 1972; Notarius & Levenson, 1979). This supports the discharge model of emotion that states that physiological responding is negatively correlated with communication accuracy (Buck et al., 1974; Buck et al., 1972). However, some studies found a positive relationship between non-verbal displays of emotional affect and physiological indices of emotional states (Lanzetta, Cartwright-Smith, & Eleck, 1976; Zuckerman, Klorman, Larrance, & Spiegel, 1981). The conflicting findings may have stemmed from differences in the operationalization of emotional expressivity across studies. Active inhibition, or the posing of a feigned emotion, may lead to a positive relationship between facial expression and physiological reactivity (Lanzetta et al. 1976). Conversely, the discharge model may account for natural expressions of emotion (Buck et al., 1974; Buck et al., 1972; Lanzetta et al. 1976).

In the current study, we examine physiological response (i.e. HRV) to emotionally arousing stimuli with the intention of identifying individuals who may be more or less facially expressive. In line with the discharge model and previous research findings (Buck et al., 1974; Buck et al., 1972), we propose that people who are more physiologically reactive (i.e. decrease in HRV) will be higher on the personality trait of introversion.

Deception and psychoticism

A significant correlation has been found between psychopathy and the personality trait of psychoticism and the Lie scale on the Eysenck Personality Questionnaire (EPQ; Hare, 1982). Specifically relevant to this study, significant correlations have also been found between a tendency towards deception and higher scores on the psychoticism and Lie scales of the EPQ (Gudjonsoon & Sigurdsson, 2004). Superficial charm, manipulation and deceptive behaviours are all features of a psychopathic personality (Edens, Buffington, & Tomicic, 2000; Hare, Forth, & Hart, 1989; Richendoller & Weaver, 1994). Thus, psychopaths may be more confident in their ability to deceive and manipulate others. However, there is paucity in the literature regarding whether this translates into actual success at deceiving others (Edens et al. 2000; Kucharski, Duncan, Egan, & Falkenbach, 2006; Poythress, Edens, & Watkins, 2001). In this study, we examine the association between psychoticism and confidence in one’s own ability to enact deceit. It is expected that people higher on the trait of psychoticism will be more confident in their ability to successfully deceive others than those lower on this trait. We also examine the relationship between psychoticism and physiological arousal related to distressing images and the thought of enacting deception. It is expected that people higher in psychoticism experience less physiological arousal (i.e. higher HRV) when stressed and during deception attempts than people lower in psychoticism.

Aims

In the current study, emotional and physiological responses to emotionally arousing stimuli and the thought of enacting deception are measured along with personality traits (i.e. introversion/extroversion and psychoticism) and deception confidence. We aim to examine how personality traits are related to one’s physiological arousal (i.e. HRV) associated with stress and deception, as well as their confidence in their ability to enact deceit. Overall, we aim to identify the characteristics of confident deceivers.

Hypotheses

By investigating three hypotheses we aim to examine the correlations between emotional and physiological arousal (i.e. HRV), introversion/extroversion and psychoticism and ultimately identify whether these characteristics impact on one’s confidence in their ability to enact deceit. We predict that: (a) Individuals with lower HRV during the deception task will have lower HRV during the stress task and will also report more distress during both tasks; (b) individuals who score higher on the personality trait of psychoticism will report less distress and have higher HRV during the stress and deception tasks and will also be more confident deceivers than individuals who score lower on psychoticism; and (c) individuals who score higher on the personality trait of introversion/extroversion (extroverts) will report less distress and have higher HRV during the stress and deception tasks.

Method

Participants

First-year psychology students (male n = 30, female n = 72), with an average age of 21.42 years (SD = 6.64) volunteered for this research as partial fulfilment of a research requirement for a first-year psychology course.

Measures

Demographic and general information questionnaire

A demographic questionnaire gathered information related to participants’ gender, age, any prescription medication they were taking that may impact their heart rate (HR), history of prior traumatic events and their thoughts, beliefs and opinions related to deception.

Eysenck Personality Questionnaire–Revised (EPQ–R; Eysenck & Eysenck, 1985)

Personality traits were measured using the Eysenck Personality Questionnaire–Revised (EPQ–R; Eysenck & Eysenck, 1985). This 48-item inventory measures four dimensions of personality: extroversion, neuroticism, psychoticism and dissimulation. The EPQ–R has been used in previous research (Gudjonsoon & Sigurdsson, 2004; Hare, 1982; Perkins, Kemp, & Corr, 2007), and in a study by Perkins, Kemp, and Corr (2007) the Cronbach’s alpha coefficients for the extroversion, neuroticism and dissimulation scales ranged from .73 to .88, indicating a good internal consistency range. However, the psychoticism scale has been found to have an internal consistency of approximately .6 (Perkins et al. 2007).

Polar RS800CX heart rate monitor

A Polar RS800CX heart rate monitor (HRM) composed of a wrist and chest band was used to measure HRV during the deception and stress tasks. The Polar RS800CX, has been found to posses sound validity, accuracy and instrument reliability for assessment of HR variability in clinical studies (Quintana, Guastella, Outhred, Hickie, & Kemp, 2012; Quintana, Heathers, & Kemp, 2012; Williams et al., 2017). Measures of HR have been used in previous research as an indicator of emotional responding (Buck et al., 1974; Buck et al., 1972). Physiological responding associated with deception has also been investigated using measures of HR (Grubin & Madsen, 2005; Meijer, Verschuere, Gamer, Merckelbach, & Ben-Shakhar, 2016; Podlesney & Raskin, 1977), most notably in polygraph testing.

The HRV for the deception task (HRV deception) was calculated by subtracting the participants’ baseline HRV while telling the truth from their HRV while enacting deceit. This indicates the difference in HRV when telling the truth and being deceptive. Similarly, the HRV for the stress task (HRV stress) was calculated by subtracting the participants’ baseline HRV while viewing stimuli that was not emotionally arousing (a turtle swimming underwater) from their HRV while viewing emotionally salient stimuli (video recording of a road traffic accident). Again, this indicates the difference in HRV when relaxed and when distressed.

Deception task

Participants were first required to imagine themselves in a scenario telling the truth (failing to attend a meeting due to illness) for two minutes while their HRV was measured in order to get a baseline measure. Participants were then required to imagine themselves in a similar scenario enacting deceit (lying about being sick to get out of a meeting) for an additional two minutes. Their HRV was again measured in order to gauge whether the thought of enacting deceit was emotionally and physiologically arousing for them. This methodology was tested in order to determine whether the thought of enacting deceit is emotionally and physiologically arousing.

Stress task

Two minutes of video footage depicting a pleasant underwater scene of a turtle swimming was used to gather baseline HRV. A second 9 min and 20 s of video footage depicting the results of a road traffic accident (Devilly & Annab, 2008) was used to determine, by again measuring HRV, whether this stimulus was emotionally and physiologically arousing.

Deception questionnaire

A questionnaire was used to gather information pertaining to how distressing the participants found the stress and deception tasks ranging from 1 (not at all distressing) through to 5 (extremely distressing) as well as their confidence in their ability to deceive on a rating scale ranging from 1 (not at all confident) through to 5 (extremely confident). Participants were asked to rate how distressing they found the video of the turtle swimming underwater (in case anybody had a fear of the ocean or turtles), the road traffic accident video and the thought of enacting deceit. However, the participants were not asked to rate how distressing they found the thought of telling the truth, as we did not believe this would cause any distress. Thus, unfortunately, we did not have a baseline measure for subjective distress during the deception task.

Procedure

Ethical approval was obtained from the Griffith University Human Ethics Research Committee (GU Ref No: PSY/70/14/HREC). Participants completed the experiment in groups of one to three while on campus. Participants were briefed concerning the background and relevance of the study prior to participation, and informed consent was obtained from all participants. Participants first completed a demographic questionnaire and the EPQ–R (Eysenck & Eysenck, 1985). Next, while wearing the HR monitor, participants first viewed two minutes of emotionally neutral video footage of an underwater scene followed by 9 min and 20 s of emotionally salient video footage of paramedics attending the scene of a road traffic accident. Heart rate variability was recorded at the end of each stimuli presentation. Next, participants completed a deception task while wearing the HR monitor. This task required the participants to first read a scenario depicting a truthful situation for two minutes and then read a scenario that involved an element of deception and imagine themselves in this scenario enacting deceit for two minutes. Heart rate variability was again recorded at the end of each stimuli presentation. Finally, participants completed a questionnaire asking how distressing they found the tasks and how confident they were in their ability to deceive.

Results

Approach to data analysis

There were no missing data. Data screening was conducted by examining the descriptive statistics and plots for each of the seven variables (i.e. introversion/extroversion, psychoticism, distress during the stress task, distress during the deception task, HRV during the stress task, HRV during the deception task and deception confidence) separately. The means and standard deviations (see Table 1) were calculated for each of the aforementioned variables. Correlational analyses and regression analyses were conducted to examine relationships between the seven variables. Statistica 13.3 was used for the correlational statistical analyses. An alpha level of .05 was used for all analyses.

Table 1.

Descriptive statistics for introversion/extroversion, psychoticism, HRV stress, HRV deception, subjective distress when stressed, subjective distress during deception and deception confidence.

Variables	M (SD)
Introversion/extroversion	7.49 (3.41)
Psychoticism	2.38 (1.71)
HRV
Relaxing stimuli	748.01 (110.99)
Stressful stimuli	728.15 (103.39)
Imagining truth	729.04 (115.25)
Imagining deception	730.06 (108.96)
Stress	−16.33 (32.05)
Deception	0.44 (23.71)
Subjective distress
Relaxing	1.16 (0.52)
Stress	3.57 (1.01)
Deception	1.87 (0.89)
Deception confidence	3.03 (1.00)

Note. HRV = heart rate variability. N = 102.

Consistent with previous research (Aluja, García, & García, 2003; Perkins et al., 2007), there was a significant difference between male and female scores on the psychoticism scale of the EPQ–R (Eysenck & Eysenck, 1985). There was also a significant difference between males and females on self-reported distress after the stress task. Therefore, we also analysed these variables by gender.

Methodology check

The validity of the deception task and the stress task are assessed via a self-report indication of distress and a physiological measure of HRV to determine whether thinking about enacting deception is emotionally and physiologically arousing enough to provide a measureable change.

Subjective distress ratings for imagining lying showed an almost perfect linear trend (positive skew), as one would expect. Therefore, non-parametric analyses were used for self-report indicators of distress. A Wilcoxon Matched Pairs Test was conducted on distress ratings while watching a relaxing video (turtle swimming underwater) and when imagining telling a lie (sending an email lying about being sick to avoid a meeting). This showed a highly significant difference in distress rating, z(n = 59) = 5.79, p < .001. Likewise, there was a very significant difference on subjective distress, between when watching a relaxing video (turtle swimming underwater) and watching a stressful video (road traffic accident), z(n = 98) = 8.60, p < .001.

Visual inspection of HRV histograms suggested the data were near normally distributed for most variables. One outlier was removed from HRV stress, and four outliers were removed from HRV deception. Review of the skew and kurtosis suggested normality was a reasonable assumption for all other variables. Means and standard deviations for the seven variables (introversion/extroversion, psychoticism, HRV stress, HRV deception, subjective distress stress, subjective distress deception and deception confidence) being investigated are presented in Table 1.

A repeated measures analysis of variance (ANOVA) on HRV while imagining telling the truth versus when imagining telling a lie did not show any significant differences, F(1, 101) = 0.036, p = .85. However, HRV when lying compared to when watching the video of the turtle swimming did show significant differences in line with subjective distress ratings as above, F(1, 101) = 59.58, p < .001.

Our interpretation of these results is that imagining lying and imagining telling the truth both reduced HRV (i.e. increasing HR) and increased subjective distress compared to watching a relaxing video. It seems that this methodology does not differentially evoke enough emotional or physiological arousal between imagining lying and imagining truth telling to provide a measurable change in HRV.

Testing relationships: subjective distress and HRV during the stress and deception tasks

The first aim of this study was to investigate the relationships between subjective distress reported after the stress and deception tasks, HRV during the stress and deception tasks and the association between reported distress and HRV after the stress and deception tasks. To assess these relationships correlations were performed.

Subjective distress reported after the stress and deception tasks

Reported levels of distress after the stress task and reported levels of distress after the deception task were significantly correlated, r(n = 102) = .40, p < .001. This indicates that participants in this sample who reported distress after watching the emotionally salient stimuli in the stress task also reported distress after imagining themselves enacting deceit in the deception task. These participants are more reactive during emotionally arousing situations.

There was an interaction effect for gender on stress levels between the deception task and the stress task. A repeated measures ANOVA found a significant effect for gender overall, F(1, 100) = 5.87, p < .017, and an effect for stress ratings between the two conditions of watching a video of a road traffic accident and imagining lying, F(1, 100) = 201.61, p < .001. The interaction effect between genders and condition was quite marked, F(1, 100) = 10.34, p = .002. In effect, females scored higher on stress ratings for both conditions, but differentially more for the video of the car accident.

Heart rate variability during the stress and deception tasks

Heart rate variability during the stress task (HRV for car accident minus HRV for turtle video) and HRV during the deception task (HRV for lying minus HRV for telling the truth) were significantly correlated, r(n = 102) = .25, p = .01.

This indicates that individuals who have lower HRV during times of stress also had lower HRV while thinking about enacting deceit.

Subjective distress and HRV after the stress and deception tasks

Reported levels of distress after the deception task and HRV during the deception task were not significantly correlated, r(n = 102) = −.05, p = .63. This indicates that participants who reported distress after the deception task did not respond in a physiologically consistent way during the deception task, if one accepts that we should expect lower HRV when stressed.

Reported levels of distress after the stress task (car accident) and HRV during the stress task were also not significantly correlated, r(n = 102) = −.12, p = .22. This indicates that participants who reported distress after the stress task did not respond physiologically during the stress task in a way that indicated they were physiologically aroused. Gender was not a factor in this lack of relationship [males: r(n = 102) = −.05, p = .81; females: r(n = 102) = −.11, p = .35].

Testing relationships: subjective distress deception, HRV deception, psychoticism and deception confidence

The second aim of this study was to investigate the association between the personality dimension of psychoticism, self-reported level of distress associated with deception, HRV during the deception task and confidence in ability to deceive others. To assess these relationships, correlations were performed (see Table 2).

Table 2.

Correlation between deception confidence, psychoticism, and subjective distress and HRV associated with deception.

	Psychoticism (N = 102)		Male psychoticism (n = 30)		Female psychoticism (n = 72)		HRV deception (N = 102)		Subjective distress deception (N = 102)
	r	p	R	p	r	p	r	p	r	p
Deception confidence	.14	.15	.26	.17	.09	.45	.06	.54	−.23	.02

Note. HRV = heart rate variability.

No significant correlation was found between participants’ level of psychoticism and deception confidence (see Table 2). This indicates that psychoticism did not mediate how confident the participants were in their own ability to enact deception.

No significant correlation was found between participants’ HRV when thinking about enacting deceit and their deception confidence (see Table 2). This indicates that people’s confidence in their own ability to deceive others had no impact on how they responded physiologically (i.e. via change in HRV) when thinking about enacting deceit.

Deception confidence and subjective distress associated with deception were significantly negatively correlated (see Table 2). This indicates that participants who were more confident in their ability to enact deceit reported less distress after imagining enacting deceit.

Testing relationships: subjective distress and HRV stress, subjective distress and HRV deception, and psychoticism

The second aim of this study was also to investigate the association between the personality trait of psychoticism and participants’ distress and HRV during the stress and deception tasks. To assess these relationships a correlation matrix is presented (see Table 3).

Table 3.

Correlation between psychoticism and subjective distress and HRV during the stress and deception tasks.

	N	HRV stress		Subjective distress stress		HRV deception		Subjective distress deception
		r	p	r	p	r	p	r	p
Psychoticism	102	.19	.06	−.26	.01*	.09	.40	−.09	.36
Male psychoticism	30	.27	.15	−.38	.04*	−.05	.77	−.44	.01
Female psychoticism	72	.12	.33	−.11	.36	.09	.48	.08	.49

Note. HRV = heart rate variability.

No significant correlation was found between HRV during the stress or deception tasks and the trait of psychoticism for the whole sample or when males and females were assessed separately. This indicates that participants’ level of psychoticism did not impact their physiological reaction (i.e. via change in HRV) to either the stress or deception tasks.

The level of distress reported after the stress task and the trait of psychoticism were significantly correlated; however, the level of distress reported after the deception task and the trait of psychoticism were not significantly correlated (see Table 3). This indicates that a participant’s level of psychoticism did not influence how distressing they found the deception task; however, it did influence how distressing they found the stress task. People higher in the trait of psychoticism reported significantly less distress after the stress task than people lower on this trait.

For males, the level of distress reported after the stress and deception tasks and the trait of psychoticism were significantly correlated (see Table 3). This indicates that males’ level of psychoticism did influence how distressing they found the stress and deception tasks. Males higher in the trait of psychoticism reported significantly less distress after the stress and deception tasks than males lower on this trait.

For females, the level of distress reported after the stress and deception tasks and the trait of psychoticism were not significantly correlated (see Table 3). This indicates that females’ level of psychoticism did not influence how distressing they found the stress and deception tasks.

Testing relationships: introversion/extroversion and subjective distress and HRV

The third aim of this study was to investigate the association between introversion/extroversion and distress and HRV during the stress and deception tasks. To assess these relationships, correlations were performed (see Table 4).

Table 4.

Correlation between introversion/extroversion and subjective distress and HRV during the stress and deception tasks.

	HRV stress (n = 102)		Subjective distress stress (n = 102)		Males subjective distress stress (n = 30)		Females subjective distress stress (n = 72)		HRV deception (n = 102)		Subjective distress deception (n = 102)
	r	p	r	p	r	p	r	p	r	p	r	p
Introversion/extroversion	−.01	.95	.01	.92	.14	.45	−.002	.98	−.12	.22	.22	.03

Note. HRV = heart rate variability.

No significant correlation was found between one’s HRV during the stress or deception tasks and the trait of introversion/extroversion (see Table 4). This indicates that one’s level of introversion/extroversion did not impact on how the participants in this sample responded physiologically (i.e. via change in HRV) to the stress or deception tasks.

The personality trait of introversion/extroversion and subjective distress associated with the stress task were not significantly correlated (when analysed as a whole group or males and females separately); however, the personality trait of introversion/extroversion and subjective distress associated with deception were significantly correlated. This indicates that one’s level of introversion/extroversion did not influence how distressing participants found the stress task; however, it did influence how distressing they found the deception task. Extroverts reported significantly more distress after the deception task than introverts.

Discussion

Overview of main findings

The aim of this study was to identify emotional, physiological and psychological characteristics of confident deceivers. To do this we examined correlations between personality traits of introversion/extroversion and psychoticism; HRV and subjective distress when stressed; and HRV and subjective distress associated with imagining enacting deceit.

Hypothesis 1

The first aim of this study was to investigate the associations between subjective distress and HRV while viewing distressing images of a road traffic accident and when thinking about enacting deceit.

Subjective distress after the stress and deception tasks

As predicted, the participants, particularly the female participants, who reported distress after watching emotionally salient stimuli that have been found to evoke stress in past studies (Devilly & Annab, 2008), also reported distress after imagining themselves enacting deceit. This indicates that the majority of people, in particular the females, who were distressed by watching emotionally salient stimuli in the stress task, also found the thought of enacting deceit to be distressing, and that these people are more reactive during emotionally arousing situations. However, when analysing the male participants, we found that those who reported distress after watching the emotionally salient stimuli in the stress task did not necessarily report distress after imagining themselves enacting deceit in the deception task or vice versa. Thus, males who are more reactive to distressing video footage seem to be less distressed by the thought of enacting deceit.

Heart rate variability during the stress and deception tasks

In addition to the positive correlation between subjective distress while viewing emotionally arousing stimuli (road traffic accident video) and while thinking about enacting deceit, findings also indicated that individuals who have lower HRV during times of stress also have lower HRV while deceiving – and vice versa. From this we can see that people physiologically react in the same way when emotionally aroused as they do while they are thinking about enacting deceit. Thus, we can conclude that the people who react physiologically (i.e. lower HRV) when viewing emotionally arousing stimuli also react physiologically (i.e. lower HRV) to thinking about enacting deceit. As both the HRV during the stress task and the HRV during the deception task decreased from the participants’ baseline HRV (relaxed), we see this finding as evidence that some individuals are more physiologically reactive during times of stress than others.

Subjective distress and HRV after the stress and deception tasks

We found both a positive correlation between subjective distress while viewing emotionally arousing stimuli (road traffic accident video) and while thinking about enacting deceit and a positive correlation between HRV during the stress task and HRV during the deception task. However, findings also indicated that participants’ reported levels of distress after both the stress and deception tasks did not significantly correlate with their HRV during the stress or deception tasks, respectively. Thus, participants who reported lower levels of distress after the stress or deception tasks did not necessarily have higher HRV (i.e. lower HR indicating resilience during times of stress) than those who reported higher levels of distress after the stress or deception tasks. Nor did participants who reported higher levels of distress after the stress or deception tasks necessarily have lower HRV (i.e. higher HR indicating emotional arousal) during the stress or deception tasks. Thus, while some people reacted emotionally (i.e. self-reports of distress) other people reacted physiologically (i.e. through a decrease in HRV) to the thought of enacting deceit.

Hypothesis 2

The second aim of this study was to investigate the association between participants’ subjective distress and HRV while considering enacting deceit and their confidence in their own ability to deceive; the association between the personality trait of psychoticism and confidence in one’s own ability to deceive was also assessed and the association between the personality trait of psychoticism and participants’ level of reported distress and HRV during times of stress and when considering enacting deception.

Subjective distress, HRV and deception confidence

Findings indicated that participant’s confidence in their own ability to enact deceit did not impact on how they responded physiologically (i.e. via changes HRV) while thinking about enacting deceit or vice versa. Thus, people who had lower HRV during the deception task, indicating they were physiologically aroused while thinking about enacting deceit, were not necessarily less confident in their own ability to enact deceit, as predicted. Nor were people who had higher HRV when thinking about enacting deception, indicating they were not emotionally aroused while thinking about enacting deceit, more confident in their own ability to enact deceit. Again, perhaps the deception task was not able to evoke strong-enough deception-related emotions to produce a measurable physiological change in this sample. However, participants’ level of self-reported distress after imagining themselves enacting deceit was negatively correlated to their confidence in their ability to enact deceit. This indicates that, as predicted, the more confident people are in their ability to deceive others the less distressing they find the idea of enacting deceit.

Psychoticism and deception confidence

Findings indicated that when assessed as a whole group, or when analysed by gender, psychoticism had no impact on people’s confidence in their ability to enact deceit. Thus, contrary to our prediction, people who were higher in the trait of psychoticism were not necessarily more confident in their own ability to deceive others. People with a psychopathic personality possess traits of superficial charm and manipulation (Edens et al., 2000; Hare et al., 1989; Richendoller & Weaver, 1994) that could contribute to a tendency towards deception. In addition, psychopaths are unlikely to experience deception-related emotions such as guilt or anxiety, and as a result are usually confident deceivers (Ekman, 1981). It may be the case that people who are true psychopaths may be more confident in their own ability to enact deceit; however, this sample did not include enough people who scored really high on the scale of psychoticism, which would give greater chance of them also scoring high on psychopathy. People who are confident in their ability to deceive others may experience fewer deception-related emotions. Therefore, deception confidence could result in less emotional leakage and cues to deception. We, therefore, see a need to investigate whether true psychopaths are more confident in their ability to enact deceit and whether this impacts on their credibility as deceivers.

Subjective distress and HRV stress, subjective distress and HRV deception, and psychoticism

It was expected that people higher in psychoticism (which has been found to relate to psychopathy; Hare, 1982) would have higher HRV during both the stress and deception tasks, indicating they are more resilient during times of stress. Contrary to our prediction, findings indicated that for the whole sample or when analysing males and females separately psychoticism had no impact on how people responded physiologically (i.e. via change in HRV) when viewing emotionally salient stimuli (road traffic accident) or when considering enacting deception. Thus, people who exhibited higher HRV (i.e. less emotional arousal) during the stress and deception tasks were not necessarily higher in psychoticism, as predicted. However, psychoticism and HRV during the stress task (watching a video of a road traffic accident) were non-significantly positively correlated (p = .06). This indicates that with a larger sample of participants who score high in psychoticism we would see a significant correlation here.

The trait of psychoticism had no impact on how distressing the whole group of participants or the female participants found the idea of enacting deceit. However, males who were higher in psychoticism reported less distress after the deception task than males lower on this trait. As previously mentioned, the deception task may not have aroused strong-enough deception-related emotions to enable us to assess emotional arousal related to deception. Additionally, we did not have a substantial number of participants who scored high on the trait of psychoticism.

In addition, females’ level of psychoticism had no impact on how distressing they found the road traffic accident video. Conversely, as expected, the whole group of participants and the male participants higher on the trait of psychoticism did report feeling less distressed by viewing the emotionally salient stimuli (i.e. paramedics attending the scene of a road traffic accident) than people who scored lower on this trait. A callous disregard for others is a central feature of a psychopathic personality. In this sample, males scored higher on psychoticism than females. This could account for the difference in these findings.

Hypothesis 3

The third aim of this study was to investigate the association between the personality trait of introversion/extroversion and self-reported distress and HRV during the stress task and when considering enacting deceit.

Subjective distress and HRV stress, subjective distress and HRV deception, and introversion/extroversion

Contrary to our hypothesis, findings indicated that the tendency to be either introverted or extraverted did not impact on how people responded physiologically (i.e. via change in HRV) to a stressful situation or an imagined deceptive interaction that may have evoked deception-related emotions (e.g. fear, guilt, delight). We predicted that, in line with previous findings (Buck et al., 1974; Buck et al., 1972; Notarius & Levenson, 1979), naturally spontaneous expressers (i.e. extroverts) would exhibit weaker physiological reactions (i.e. skin conductance and HR) in response to emotionally arousing stimuli than natural inhibitors (i.e. introverts). While the video footage of paramedics attending the scene of a road traffic accident used in the stress task has been found to evoke stress in past studies (e.g. Cheung, Garber & Bryant, 2015; Devilly & Annab, 2008), as previously mentioned, the deception task (imagining enacting deceit) may not have evoked strong emotions in this sample. Therefore, a task that involves enacting deception is needed to further examine physiological arousal associated with deception.

In addition, when analysing the participants as a whole group or males and females separately, the level of introversion/extroversion did not influence how distressing participants found the stress task. Therefore, neither introverts nor extroverts were more likely to report feeling distressed after viewing the scene of a road traffic accident. However, the trait of introversion/extroversion did influence how distressing participants as a whole found the deception task. Extroverts reported significantly more distress after the deception task than introverts. This is contrary to our initial prediction. We believed introverts, with their typically more timid natures, would be more distressed by the thought of enacting deceit. It is also possible that the extremely distressing nature of the car accident may have washed out any effects, it being exceptionally distressing for most people to watch (Cheung et al., 2015).

Applications of main findings

This study was designed to differentiate individuals who may be good and bad at enacting deceit. This was done with the aim of identifying participants to be utilized in future research that will further examine the ability of people to enact deceit. In this study we aimed to identify personality traits and patterns of emotional and physiological arousal that may impact on individuals’ confidence as deceivers. We further considered how these traits may influence the ability of people to enact deception. Identifying personal characteristics that may make for confident, credible deceivers could be beneficial when trying to identify deception cues and leakage in order to train people to detect deception.

Strengths and limitations of the study

The research observations in this study reflect the true effects in this population and are considered to be sound due to the sizable student sample that is representative of both genders. In this study we ultimately aimed to identify an emotional, physiological and behavioural profile that may be an indication of deception ability. These findings put us one step closer to identifying optimal personal characteristics of credible deceivers.

It is a limitation to this study that within this sample (undergraduate students) we did not have many participants with truly high scores on the measure of psychoticism, with the majority of the participants not scoring over the population mean for their gender on this trait (males: M = 3.69, SD = 2.48; females: M = 2.97, SD = 2.22; Aluja et al., 2003).

Further, the deception task did not seem sufficient to evoke strong deception-related emotions (i.e. distress, apprehension, guilt, delight), with no real change in HRV being observed between imagining a truthful scenario and imagining enacting deception. This may be due to participants not completing the task properly or the fact that merely imagining enacting deceit does not arouse strong-enough emotions to cause measureable physiological change via HRV.

Future research directions

Future studies could investigate different psychological characteristics and attempt to determine whether or not they impact on deception confidence. The psychological characteristics investigated in the current study could also be examined among forensic populations. People who are higher in psychoticism and high in psychopathy may have a unique physiological profile associated with emotional arousal while enacting deception that could influence their confidence in their ability to deceive or their credibility as deceivers. As psychoticism and HRV while watching emotionally salient stimuli (video of a road traffic accident) came close to significance, we believe that with a larger sample of participants who score high in psychoticism we would see a significant correlation here. This needs to be tested as it is unknown whether psychopaths are emotionally or physiologically aroused during deceptive interactions in the same way as others. People higher in psychoticism and psychopathy may not experience as much physiological arousal (i.e. change in HRV) during deceptive communication as people lower in these traits, as they may not experience deception apprehension or guilt. As a result, psychopaths may display minimal leakage or behavioural cues to deception. However, psychopaths may experience duping delight (excitement caused by duping others), which could cause physiological arousal. The deception task would need to be altered in order to ensure it evoked strong-enough deception-related emotions to cause changes in physiological arousal.

Conclusion

Overall, this study has shown that while some people have a tendency to react emotionally (i.e. self-reports of distress), other people are more likely to react physiologically (i.e. through a decrease in HRV) to emotionally arousing stimuli and to the thought of enacting deceit. While we initially predicted that this style of responding would coincide with a level of introversion and extroversion, this personality trait did not seem to moderate the tendency to react emotionally or physiologically to the tasks in this study.

We examined the difference in physiological response to emotionally salient stimuli and the thought of enacting deceit between introverts and extroverts with the intention of identifying individuals who may be more or less facially expressive. While previous studies have suggested that extroverts exhibited weaker physiological reactions in response to emotionally arousing situations than introverts (Buck et al., 1974; Buck et al., 1972; Notarius & Levenson, 1979), conflicting research findings suggest that extroverts exhibit stronger physiological reactions in response to emotionally arousing situations than introverts (Lanzetta et al. 1976; Zuckerman, et al., 1981). In line with the discharge model and previous research findings (Buck et al., 1974; Buck et al., 1972), we proposed that people who are more physiologically reactive would be higher on the personality trait of introversion (less facially expressive). However, contrary to our prediction our findings indicated that one’s tendency to be either introverted or extroverted had no impact on physiological arousal when viewing emotionally salient stimuli (road traffic accident) or when considering enacting deceit. While we have determined that our deception task (thinking about enacting deceit) may not have been sufficient to evoke physiological arousal, the video footage of paramedics attending the scene of a road traffic accident has been found to evoke stress in past studies. Thus our findings do not provide support for the previous research findings. However, extroverts did report that they felt more emotionally aroused (distressed) by the thought of enacting deception than introverts. Thus, in conjunction with desynchrony (emotional arousal and physiological arousal varying inversely or out of synchronicity), while the extroverts were not physiologically aroused during the deception task, they did report feeling emotionally aroused after the task.

Contrary to our initial prediction, the personality trait of psychoticism did not moderate how physiologically aroused the participants were in response to viewing emotionally salient stimuli (i.e. road traffic accident) or the thought of enacting deceit. Also contrary to our prediction, the personality trait of psychoticism was not related to how emotionally arousing the group as a whole or the female participants found the thought of enacting deceit. However, in line with our hypothesis, males who were higher in psychoticism reported less subjective distress after thinking about enacting deceit than males lower on this trait. In addition, females’ level of psychoticism had no impact on how distressing they found the road traffic accident video. Conversely, as expected, the whole group of participants and the male participants higher on the trait of psychoticism were less emotionally aroused (self-reported distress) after viewing stimuli depicting others in distress (i.e. paramedics attending the scene of a road traffic accident) than people who scored lower on this trait.

Due to the characteristics associated with psychoticism (typical high scorers are characterized as aggressive, non-conformist, tough-minded, inconsiderate, reckless and impulsive), we expected people who were higher in the trait of psychoticism to be more confident in their ability to deceive others. However, contrary to our prediction, the personality trait of psychoticism had no impact on people’s confidence in their ability to enact deceit. Further investigation into how psychoticism impacts on deception confidence utilizing a sample that score higher on this trait is warranted. We also expected that deception confidence would decrease the experience of emotional arousal and in turn physiological arousal while thinking about enacting deception. However, participants’ confidence in their ability to enact deceit had no impact on how they responded physiologically (i.e. via changes HRV) while thinking about enacting deceit or vice versa. However, participants’ level of self-reported distress after imagining themselves enacting deceit was negatively correlated to their confidence in their ability to enact deceit. This indicates that, as predicted, the more confident people are in their ability to deceive others, the less distressing they find the idea of enacting deceit.

This investigation into psychological characteristics that may impact on the ability to successfully enact deceit has identified personal characteristics (i.e. psychoticism and emotional and physiological arousal) for further investigation, ideally using a different sample population (i.e. forensic population).

Ethical standards

Declaration of conflicts of interest

Candice McBain has declared no conflicts of interest.

Grant J. Devilly has declared no conflicts of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee [add as appropriate] and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Ethical approval was obtained from the Griffith University Human Ethics Research Committee (GU Ref No: PSY/70/14/HREC).

Informed consent

Informed consent was obtained from all individual participants included in the study

Transparency declaration

The lead author affirms that this manuscript is an honest, accurate and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

Authors’ contributions

Grant J. Devilly contributed to the larger research programme, designed the research, obtained ethics clearance, analysed the data and wrote the manuscript. Candice McBain contributed to the larger research programme, designed the research, obtained ethics clearance, collected and transformed the data, assisted with data analysis and wrote the manuscript.

Licence to publish

Exclusive licence to publish this article is given.