Compared to all other age groups, infants have faces that are most successful at capturing attention, a recent Yale Child Study Center and University College London joint study confirmed.

Researchers asked participants — 84 adult women, roughly half of whom were mothers — to complete a visual search task that contained three faces from the same age group. One face had a different eye color from the others. When infant faces were present on the screen, a much slower response time in identifying the different eye color was recorded than when faces of any other age group were shown. In particular, infant faces in distress effectively attracted the most attention, and thus distracted participants from completing the visual search task on time. The attentional engagement is further highlighted in the 39 mothers compared to the 45 non-mothers. Researchers found that participants did not process adolescent and adult faces differently, and thus gave neither preferential treatment. While sad pre-adolescent child faces also led to greater attentional allocation, baby faces ultimately won the game.

“These findings further demonstrate the salience of infant faces in capturing attention, replicating our previous work, but also advancing it to understand this from a developmental perspective with increasing age of the non-adult faces,” said study co-authors Linda Mayes, professor of Child Psychiatry, Pediatrics and Psychology, and associate research scientist Helena Rutherford at the Yale School of Medicine.

The researchers’ interest in the intrinsic salience of infant faces and its effect on caregiving behavior in parents initially sparked this study, they explained, adding that they are at the beginning of a series of experiments exploring the neuro-cognitive mechanisms at play in parenting.

Past studies have already established that infant faces have a special capacity for attracting attention, but researchers remain unsure if this ability is unique to infants only. By incorporating pre-adolescent child and adolescent faces into an existing visual search task that previously compared only infant and adult faces, Mayes, Rutherford and their colleagues at UCL illustrated an inverse relationship between attentional allocation and age. The emotional states of the faces, especially the display of negative emotions, and mother versus non-mother status of the participants also proved to be significant factors in engaging their attention.

According to study contributing author and trainee clinical psychologist at UCL Chloe Thompson-Booth, this study demonstrates that the baby schema — the round face, chubby cheeks, large eyes, small mouth and tiny nose, features that people find extremely cute in babies — exists for a reason. Without verbal communication, infants must rely on facial expressions and vulnerability cues to engage the attention of their caretakers.

“It is very important for babies to be able to attract our attention so that we can give them the appropriate care,” said Thompson-Booth, suggesting that there is something innate about their particular facial configuration. She added that the baby schema applies not only to human babies but also to the very young of all species, and this appearance seems to trigger a “biological drive for us to take care of these very cute and vulnerable-looking faces.”

Mayes and Rutherford added that researchers hypothesize that parents may be biologically programmed to find infant faces rewarding, serving an evolutionary purpose to increase infants’ chances of survival.

Their study is also of clinical interest, they noted, as understanding normal attentional allocation to human faces will help them examine possible factors contributing to lower-quality parenting, especially among mothers with anxiety, depression and addiction.

Currently, Dr. Chloe Thompson-Booth is collecting data from a paternal sample completing the same task to examine attentional allocation in fathers.

The study was published in the online journal PLoS ONE on Oct. 29.