Toddlers’ Affective Responses to Sociomoral Scenes Insights From Physiological Measures

Abstract

A growing literature suggests preverbal infants are sensitive to sociomoral scenes and prefer prosocial over antisocial agents. It remains unclear, however, whether and how emotional processes are implicated in infants’ responses to prosocial/antisocial actions. Although a recent study found infants and toddlers showed more positive facial expressions after viewing helping (vs. hindering) events, these findings were based on naïve coder ratings of facial activity; further, effect sizes were small. The current studies examined 18- and 24-month-old toddlers’ real-time reactivity to helping and hindering interactions using three physiological measures of emotion-related processes. At 18 months, activity in facial musculature involved in smiling/frowning was explored via facial electromyography (EMG). At 24 months, stress (sweat) was explored via electrodermal activity (EDA). At both ages, arousal was explored via pupillometry. Behaviorally, infants showed no preferences for the helper over the hinderer across age groups. EMG analyses revealed that 18-month-old infants showed higher corrugator activity (more frowning) during hindering (vs. helping) actions, followed by lower corrugator activity (less frowning) after hindering (vs. helping) actions finished. These findings suggest that antisocial actions elicited negativity, perhaps followed by brief disengagement. EDA analyses revealed no significant event-related differences. Pupillometry analyses revealed that both 18- and 24-month-olds’ pupils were smaller after viewing hindering (vs. helping), replicating recent evidence with 5-month-olds and suggesting that toddlers, too, show less arousal following hindering than following helping. Together, these results provide new evidence with respect to whether and how arousal/affective processes are involved when infants process sociomoral scenarios.

Preverbal infants’ understanding of social norms

“…Infants discriminate positive and negative facial expressions towards the end of their second year of life 45 . Likewise, previous studies demonstrated that actions of moving towards each other 13 as well as facial expressions 46 are also differentiated by infants (and elicit meaningful effects on measures of pupil dilation 25 ) for geometrically shaped characters. In addition, while former studies used explicit verbal expressions of praise and admonishment 47 here we created novel sounds to support the characters approval or disapproval.…”

“…That is, based on the studies reviewed above 13,16,[20][21][22][23][24] , do infants in their first year already understand that the conformity with the behavior of others has social consequences, conforming behavior being socially approved (i.e., reinforced), but non-conforming behavior being socially disapproved (i.e., sanctioned), which is a key marker of social norms 4,5 ? Here it is crucial to test infants' responses to novel, arbitrary, actions, to go beyond the social evaluations towards behaviors that have themselves positive connotations because they are supportive of others' needs (e.g., helping versus hindering 13,25 ). These behaviors may be associated with positive (versus negative) responses either naturally, or based on infants former learning experience.…”