Infants’ looking preferences for social versus non-social objects reflect genetic variation

Abstract

To what extent do individual differences in infants’ early preference for faces versus non-facial objects reflect genetic and environmental factors? In a sample of 536 5-month-old same-sex twins, we assessed attention to faces using eye-tracking in two ways: initial orienting to faces at the start of the trial (thought to reflect subcortical processing) and sustained face preference throughout the trial (thought to reflect emerging attention control). We show that both face orienting and preference were heritable (h2 = .19, CI: .04-.33; h2 = .46, CI: .33-.57, respectively); while shared environment was statistically nonsignificant. Face preference was associated positively with later parent-reported verbal competence (Beta = 0.14, p = .014). This is the first study to show that individual differences in young infants’ selection of perceptual input – social versus non-social – are heritable, providing a new developmental perspective on gene-environment interplay occurring at the level of eye movements.

Oxytocin but not naturally occurring variation in caregiver touch associates with infant social orienting

“…In particular, preferential attending to eye and mouth regions of the face was the most heritable of the social attention characteristics measured in their study (Constantino et al., 2017), a finding consistent with what was later reported with regard to attention to faces relative to nonsocial objects by Portugal et al. (2022). Although the exact genes involved were not investigated in these studies, previous research demonstrated that the oxytocin receptor gene (OXTR) is involved in modulating infant neural response to emotional faces (Krol, Puglia, et al., 2019).…”

“…Furthermore, it is also possible that social attention in infancy is not subject to much environmental influence (Constantino et al, 2017;Portugal et al, 2022). Constantino et al (2017) found that the way infants view social scenes is strongly influenced by genetic factors.…”

“…Furthermore, it is also possible that social attention in infancy is not subject to much environmental influence (Constantino et al., 2017; Portugal et al., 2022). Constantino et al.…”

“…In this study, we used it to assess infants’ interest in faces as compared to nonsocial stimuli, to verify whether touch and related measures of arousal can affect the distribution of attention. Thus, the measure of interest was the proportion of time the infants spent looking at the face stimulus (i.e., infant's gaze was within a rectangular area of interest around the face) with respect to the total time they spent looking at a slide (de Klerk et al., 2014; Elsabbagh et al., 2013; Portugal et al., 2022; Telford et al., 2016). This proportion was computed for each slide where the infant's gaze was on the screen for at least 6.7 s of the time of its presentation (67% of the time; analogous to de Klerk et al., 2014; Elsabbagh et al., 2013).…”

“…When measuring social preference, a more complex scene in which nonsocial stimuli are presented alongside faces could be a more sensitive and consequently more appropriate approach. Importantly, social preference measured in such a way has recently been shown to predict later language development (Portugal et al., 2022). Indeed, in 4‐ to 6‐year‐old children, naturally occurring variation in caregiver touching patterns (as observed during an interactive play session) correlated with attention to social stimuli.…”