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. Author manuscript; available in PMC: 2022 Nov 1.
Published in final edited form as: Biol Psychol. 2021 Oct 16;166:108207. doi: 10.1016/j.biopsycho.2021.108207

Did You Say My Name? Congruency of 12-month-old Infants’ Behavioral and Cardiac Responses to Name

Wei Siong Neo 1, Bridgette L Kelleher 1
PMCID: PMC8643321  NIHMSID: NIHMS1748899  PMID: 34662674

Abstract

Reduced orienting to name is an early behavioral risk marker for neurodevelopmental disorders. However, individual instances of infants’ behavioral responses to name are limited in both reliability and predictive validity. Physiological responses such as heart rate (HR) deceleration may serve as more sensitive metrics than behavioral methods. As a first step toward validating HR deceleration as a candidate psychophysiological measure of name processing, we examined the congruency of behavioral and cardiac responses to name in 12-month-old typically developing infants. Infants exhibited greater median HR deceleration and spent a larger proportion of time in HR deceleration when they behaviorally oriented to their names than when they failed to do so; however, maximum HR deceleration was not related to behavioral responses. These findings provide preliminary evidence that specific HR deceleration metrics may be useful indices of infants’ responses to name and may inform psychophysiological mechanisms underlying behavioral responses.

Keywords: response to name, heart rate deceleration, infant, attention, orienting response, autism spectrum disorder

Our names are salient auditory stimuli that capture our attention and prompt behavioral responses. Such responses emerge in the first year of life and are critical for social-communicative development (Scharf et al., 2016), and infants who exhibit diminished responses to name at behavioral (Hatch et al., 2021) and neural levels (Arslan et al., 2020) are more likely to be diagnosed with autism spectrum disorder (ASD). Although several developmental screening and diagnostic instruments assess responses to name, name response is rarely considered in isolation because attentional, motivational, and social factors may yield inconsistent behavioral responses (Key et al., 2016). Prior studies, for example, have documented that a lack of behavioral response to name by itself has limited sensitivity and positive predictive value for identifying ASD, though sensitivity and specificity may be acceptable when considering responses across longitudinal assessments (Miller et al., 2017; Nadig et al., 2007).

Physiological responses to name may serve as more sensitive metrics than behavioral methods, with heart rate (HR) deceleration holding particular promise. Indeed, HR deceleration has been used to index attentional processes and phases in clinical and developmental research for over five decades, resulting in well-established attentional models (Graham & Clifton, 1966; Sroufe & Waters, 1977). Per these models, infants exhibit a large HR deceleration lasting about five seconds when orienting attention to external stimuli (Reynolds & Richards, 2008). In contrast to more costly or cumbersome neuroimaging approaches, cardiac measures are well suited for translational applications at scale. HR-based approaches are inexpensive and portable, affording naturalistic studies with high ecological validity. Cardiac measures are also feasible for neurodevelopmental research due to ease of data collection from individuals with varying functional levels and few participation demands (de Haan, 2015).

Importantly, altered cardiac functioning has been observed in ASD, as evidenced in various cardiac measures (e.g., HR and HR variability; Klusek et al., 2015). When shown faces with a direct gaze, children with ASD experience HR acceleration instead of the typical deceleration (Helminen et al., 2017), suggesting different cardiac responses to social stimuli. Similarly, infants with varying likelihood of developing ASD displayed differential HR deceleration patterns in auditory and visual domains (Perdue et al., 2017; Tonnsen et al., 2018), with HR deceleration providing enhanced sensitivity in distinguishing between low- and high-likelihood infants than behavioral data alone (Tonnsen et al., 2018). Cardiac responses to name may likewise yield incremental value beyond behavioral responses, reflecting occasional divergence of behaviors from physiological processes (Brez & Colombo, 2012; Elsabbagh & Johnson, 2010).

An important first step toward understanding how abnormal HR decelerations relate to social-communicative challenges in ASD is to establish whether behavioral and HR deceleration responses are associated in typical development. This work may inform whether cardiac measures may be more objective and sensitive than behavioral approaches, potentially offering more clinical utility in understanding neurodevelopmental outcomes such as ASD. It is also important to determine which HR deceleration metrics are most suitable for characterizing single-trial responses to name; in past studies, psychophysiological researchers have quantified HR deceleration using maximum HR deceleration (Erlich et al., 2013), mean/median HR deceleration (Miller et al., 1987; Perdue et al., 2017), and proportion of time in HR deceleration (Tonnsen et al., 2018). Establishing which HR deceleration metrics would best capture cardiac responses to name may in turn enable optimal operationalization.

The Present Study

The present study examined the congruency between behavioral and cardiac responses to name in 12-month-old, typically developing infants. Given enhanced infants’ neural responses to own names and a decelerated HR for speech stimuli (Parise et al., 2010; Perdue et al., 2017), our primary prediction was that HR deceleration would be greater when infants responded behaviorally to their names than when they failed to do so. Given multiple operationalizations of HR deceleration, our secondary aim was to explore which HR deceleration metrics most closely align with behavioral responses. We expected all HR deceleration metrics to be congruent with behavioral responses and compared these metrics exploratorily.

Method

Participants

Participants included 34 infants (52.9% male) with a mean age of 12.27 months (SD = 0.91), gestational age of at least 37 weeks, no known developmental concerns, and no first-degree familial history of ASD or intellectual disabilities. Mothers provided informed consent and Purdue University’s institutional review board approved all procedures.

Measure

We leveraged existing data from the Autism Observation Scale for Infants (AOSI; Bryson et al., 2008) and focused on the “response to name” behavioral press (Figure 1). Briefly, infants participated in at least two and up to six trials, with the number of administered trials contingent on behavioral responses. Per AOSI scoring protocol, we classified each trial as (a) Behavioral Response if infants turned toward the individual calling their names within two seconds; or (b) Behavioral Non-Response if infants failed to do so.

Figure 1. Administration Details of “Response to Name” Behavioral Press.

Figure 1

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Note. The “response to name” behavioral press involves name call trials embedded within Free Play Period 1, Free Play Period 2, and Supplemental Presses of the Autism Observation Scale for Infants (AOSI; Bryson et al., 2008). Each infant participated in up to six name call trials, organized into three blocks of two trials each, with Blocks 1 and 2 administered by researchers and Block 3 administered by infants’ mothers. Given the semi-structured nature of the AOSI, each block of trials was administered when the infant was judged to be engaging with toys, with the second trial of each block occurring approximately five seconds after the first trial. Trials 1 and 3 were always administered; trials 2 and 4 were administered if infants failed to respond behaviorally in the previous trial; and trials 5 and 6 were administered if infants failed to respond behaviorally for all previous trials.

Behavioral Data

Using AOSI video recordings, we coded onset and offset of infants’ names for all individual trials in ELAN (Max Planck Institute for Psycholinguistics, 2020). Name onset and offset were defined as start of the first phoneme and end of the last phoneme, respectively. Two behavioral coders independently assessed onset and offset times to the nearest 100 ms; interrater consistency was high, with mean absolute difference of 2.63 ms (SD = 16.04).

Cardiac Data

We collected infant cardiac activity using a single-channel HR monitor and processed electrocardiograph (ECG) signals offline. First, we extracted five seconds of ECG signals before onset and after offset of infants’ names. Second, two physiological coders independently marked R-waves in QRSTool (Allen et al., 2007); interrater reliability was excellent, with mean Cohen’s κ of 1.00 (SD = 0.00). Third, we computed interbeat intervals (IBIs) using marked R-waves. Fourth, we calculated baseline IBI, defined as median IBI during the pre-name call period. Fifth, we subtracted baseline IBI from individual IBIs in the post-name call period such that increased and decreased IBIs indexed HR deceleration and acceleration, respectively. Finally, we operationalized cardiac responses using three metrics: (a) maximum HR deceleration; (b) median HR deceleration; and (c) proportion of time in HR deceleration (Figure 2).

Figure 2. Illustration of Heart Rate (HR) Deceleration Metrics from Individual Name Call Trials.

Figure 2

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Note. For each individual name call trial, the degree of HR deceleration in the post-name call period was determined relative to baseline interbeat interval (IBI) from the pre-name call period. We determined three HR deceleration metrics: (1) maximum HR deceleration; (2) median HR deceleration; and (3) proportion of time in HR deceleration.

Analytic Plan

Given age, sex, and familiarity/novelty effects on cardiac activity (Imafuku et al., 2014; Rijnbeek et al., 2001), we first used Spearman’s correlations and Wilcoxon rank-sum tests to evaluate whether such covariates were significant and had to be accounted for in primary analyses. To examine congruency of infants’ behavioral and cardiac responses to name, our primary analyses contrasted HR deceleration during Behavioral Response and Non-Response trials using Wilcoxon rank-sum tests; we expected greater HR deceleration in Behavioral Response trials across all three HR deceleration metrics.

Results

Descriptive Statistics

Infants displayed varied behavioral responses across a total of 114 trials (Figure 3). On average, an infant participated in 3.35 trials (SD = 1.20). Specifically, 7 (20.6%) infants consistently responded behaviorally, 7 (20.6%) infants consistently failed to respond behaviorally, and the remaining 20 infants (58.8%) demonstrated inconsistent behavioral responses.

Figure 3. Summary of Behavioral Responses for Individual Infants.

Figure 3

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Note. Each row represents an individual infant, with a circle indicating the administration of a trial. Trials 1 through 4 were administered by researchers; trials 5 and 6 were administered by infants’ mothers. Unfilled circles indicate that infants failed to orient to their names behaviorally (Non-Response); filled circles indicate that infants turned toward the individual who called them (Response). Due to administration errors or infant noncompliance, shaded individual infants (n = 7) contain missing data.

On average, an infant had 10.58 (SD = 0.70) and 10.51 (SD = 0.76) heartbeats during the pre- and post-name call periods, respectively. Infants exhibited substantial variation in their cardiac responses across HR deceleration metrics (Table 1 and Figure 4) and trials (Supplemental Figure 1). All three HR deceleration metrics were greater for Behavioral Response than Non-Response trials and for mother-administered than researcher-administered trials.

Table 1.

Descriptive Statistics of Heart Rate (HR) Deceleration Metrics

Metric 1: Maximum HR deceleration (ms)
 Metric 2: Median HR deceleration (ms)
 Metric 3: Proportion of time in HR deceleration
Trial Type n M (SD) Mdn Range M (SD) Mdn Range M (SD) Mdn Range
Full sample 114 29.17 (36.74) 21.48 −21.97–185.55 1.23 (25.66) −1.47 −46.88–93.26 .50 (.37) .47 .00–1.00
Behavioral response
 Non-response 76 26.59 (35.83) 19.29 −21.97–177.73 −2.18 (24.64) −3.42 −46.88–93.26 .45 (.35) .39 .00–1.00
Response 38 34.34 (38.47) 28.08 −17.58–185.55 8.03 (26.62) 6.35 −38.58–71.29 .60 (.37) .65 .00–1.00
Trial administrator
Researcher 106 28.27 (37.44) 18.80 −21.97–185.55 0.03 (25.77) −2.69 −46.88–93.26 .47 (.36) .41 .00–1.00
 Mother 8 41.20 (24.16) 32.96 21.48–95.70 17.09 (18.96) 15.14 −13.67–42.97 .83 (.19) .88 .47–1.00
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Note. Mdn = Median.

Figure 4. Heart Rate (HR) Deceleration Metrics as a Function of Behavioral Response.

Figure 4

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Note. Infants’ cardiac responses, operationalized using three HR deceleration metrics (Panel A: maximum HR deceleration; Panel B: median HR deceleration; Panel C: proportion of time in HR deceleration), are shown for trials where infants failed to orient to their names behaviorally (Non-Response) versus trials where infants turned toward the individual who called them (Response).

Preliminary Analyses

Preliminary analyses indicated multilevel models (i.e., trials nested within infants) were unnecessary (Supplemental Tables 1 and 2). HR deceleration metrics did not vary by infant’s age (−.06 < rss < −.03, .497 < ps < .719) nor sex (0.24 < Zs < 0.52, .600 < ps < .807), thus these demographic characteristics were excluded from primary analyses. Infants experienced at least marginally greater HR deceleration during mother-administered than researcher-administered trials (maximum: Z = 1.75, p = .080; median: Z = 2.28, p = .023; proportion of time: Z = 2.66, p = .008). However, with only eight (7.0%) trials administered by infants’ mothers, we collapsed across researcher-administered and mother-administered trials for primary analyses.

Primary Analyses

Figure 4 and Table 2 contrast infants’ cardiac responses when they behaviorally responded to their names versus when they failed to do so. Consistent with our prediction, median HR deceleration was greater by 10.21 ms and proportion of time in HR deceleration was 15.4% greater for Behavioral Response than Non-Response trials. However, maximum HR deceleration did not differ between Behavioral Response and Non-Response trials. Separate supplemental analyses of researcher-administered (maximum: rpb = .08; median: rpb = .19; proportion of time: rpb = .18) and mother-administered (maximum: rpb = .46; median: rpb = .36; proportion of time: rpb = .16) trials yielded effect sizes that were similar to or larger than those for all trials (Table 2), suggesting that observed effects across all three HR deceleration metrics were robust.

Table 2.

Comparisons of Heart Rate (HR) Deceleration Metrics by Behavioral Response

Non-Response (n = 76)
 Response (n = 38)
 Wilcoxon Rank-Sum Test
HR Deceleration Metric M SD M SD Z p r pb
Maximum HR deceleration (ms) 26.59 35.83 34.34 38.47 1.18 .236 .11
Median HR deceleration (ms) −2.18 24.64 8.03 6.35 2.11 .035 .20
Proportion of time in HR deceleration .45 .35 .60 .37 2.07 .038 .19
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Note. Significant (p < .05) effects are shown in bold.

Discussion

The present study, to our knowledge, is the first to examine the congruency between behavioral and cardiac responses to name in typically developing infants, (1) informing how physiological attention is involved in infant name processing during semi-structured interactions and (2) laying the foundation for potentially using HR deceleration as a psychophysiological marker of name processing in translational clinical applications. We obtained preliminary evidence that HR deceleration may index infants’ behavioral responses to name. Specifically, infants exhibited greater median HR deceleration and larger proportion of time in HR deceleration, but not greater maximum HR deceleration, when responding behaviorally to their names.

The differential findings across HR deceleration metrics may stem from methodological artefacts. Median HR deceleration and proportion of time in HR deceleration considered all IBIs in the post-name call period, whereas maximum HR deceleration was determined by a single IBI which would be sensitive to spontaneous infant IBI fluctuations (Rosenstock et al., 1999). Nevertheless, some studies have successfully used maximum HR deceleration to assess orienting responses for emotionally salient stimuli (Erlich et al., 2013; Vos et al., 2012), albeit across more trials than occurred in the AOSI, suggesting the need for methodological studies to inform optimal selection of distinct HR deceleration metrics for specific study and task designs.

Importantly, our sample of typically developing infants exhibited diverse behavioral and cardiac responses. Consistent with previous estimates (e.g., 14.3% in Miller et al., 2017), 20.6% of infants in our sample consistently failed to behaviorally respond to their names. Furthermore, across all infants, the number of Behavioral Non-Response trials was twice that of Response trials. These observations highlight how behavioral responses to name can be inconsistent even in typical development.

More broadly, using the AOSI to examine infants’ responses to name has both advantages and inherent constraints. The “response to name” behavioral press has strong parallels to diagnostic assessment protocols for ASD and real-world social communication patterns. Therefore, by leveraging the AOSI, the present study advances our understanding of infants’ behavioral and cardiac responses to name in relatively naturalistic contexts, with potential to inform translational applications. Nevertheless, the limited number and structured timing of name call trials in the AOSI are inadequate for examining heterogeneous behavioral and cardiac responses. Infants might have been at various states of attentional engagement with toys and the environment when their names were called, thereby influencing the degree of behavioral and cardiac responses. Experimental tasks with multiple trials will facilitate probing of factors that may influence infant name processing, including identity of trial administrator and pre-name call behavioral and physiological attentional states.

Further research is needed to address the present study’s limitations, including a small sample size and limited sociodemographic diversity (i.e., primarily White, educated, and well-resourced families). While we employed nonparametric statistics appropriate for small samples, replicating our findings in larger, more diverse samples will be crucial. Additionally, to inform the generalizability of HR deceleration metrics, future work should extend beyond infants’ own names to other socially meaningful stimuli (e.g., faces). Given the substantial overlap of infants’ cardiac responses across Behavioral Response and Non-Response trials as well as relatively small effect sizes, it will be valuable to explore possibilities for enhancing signal-to-noise ratios of HR deceleration metrics (e.g., refining mother-administered trials). Nevertheless, the present study offered tentative evidence that HR deceleration holds promise as a sensitive, portable, cost-effective psychophysiological measure for infant name processing.

Supplementary Material

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Highlights.

  • Responding to our names is a significant developmental milestone in infancy.

  • We examined the congruency of infants’ behavioral and cardiac responses to name.

  • Median heart rate (HR) deceleration was greater during behavioral responses.

  • Proportion of time in HR deceleration was also greater during behavioral responses.

  • HR deceleration may serve as a psychophysiological measure of name processing.

Acknowledgments

The data that support the findings of this study are openly available in an Open Science Framework repository at https://osf.io/xbqes. We have no conflicts of interest to disclose. This work was supported by the National Institutes of Health [K23MH111955].

Footnotes

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Supplementary Materials

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NIHMS1748899-supplement-1.docx (3.2MB, docx)
2
NIHMS1748899-supplement-2.docx (15KB, docx)
3
NIHMS1748899-supplement-3.docx (19.2KB, docx)

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