Infant-Caregiver Affect Attunement

Infant-caregiver affect attunement is the sharing of emotional experiences through the matching of expressions during dyadic face-to-face interaction between infants and caregivers. This is a human-unique strategy for social engagement, yet it is mediated by culture and is therefore shows variability across human populations. There are very few reports of mutual gaze in mother-infant dyads among our closest primate relatives. Though human-reared chimpanzees exhibit extended eye contact with their caregivers, there is no evidence for infant-caregiver affect attunement among mother-reared nonhuman primates as it is currently defined. However, this does not mean the capacity is not there because it may just be a reflection of different modalities used for social engagement, given that mother-reared chimpanzees interact with infants primarily through cradling and physical contact, which is inversely correlated with time spent in mutual eye contact and face-to-face interaction.

Infant-caregiver affect attunement is a precursor to other important social cognitive capacities of humans such as joint attention, cultural learning, and theory of mind. It is likely to have emerged in homo erectus along the same trajectory as similar social cognitive capacities thought to be present in the homo line. As humans navigated an increasingly complex social environment, the need to understand the emotions of conspecifics became an important selection pressure. In addition, the biological and behavioral neoteny of human infants elicited increased attention and care from adults, thus increasing opportunities for infant-caregiver interaction. For example, the extended duration of breastfeeding associated with a prolonged period of early development and brain growth in humans provides increased opportunities for maternal-infant face-to-face interaction. Another potential biological mechanism for infant-caregiver affect attunement is the release of oxytocin that occurs during maternal-infant touch and mutual eye gaze, reinforcing the social bond that is facilitated by infant-caregiver interaction.

Culture plays a large role in mediating the occurrence of infant-caregiver affect attunement, as the evidence for this behavior in modern humans varies with cross-cultural differences in parenting goals, infant carrying style, subsistence demands, etc. Infant-caregiver affect attunement is seen most often in Western, educated, industrialized populations where face-to-face interaction is the normative pattern of social engagement and communication. The lack of occurrence in many other cultures could be attributed to less emphasis on face-to-face contact (in comparison with Western parent-infant dyads), rather than to a lack of ability.