Why are faces denser in the visual experiences of younger than older infants?

Abstract

Recent evidence from studies using head cameras suggests that the frequency of faces directly in front of infants declines over the first year and a half of life, a result that has implications for the development of and evolutionary constraints on face processing. Two experiments tested two opposing hypotheses about this observed age-related decline in the frequency of faces in infant views. By the People-input hypothesis, there are more faces in view for younger infants because people are more often physically in front of younger than older infants. This hypothesis predicts that not just faces but views of other body parts will decline with age. By the Face-input hypothesis, the decline is strictly about faces, not people or other body parts in general. Two experiments, one using a time-sampling method (84 infants 3 to 24 months in age) and the other analyses of head camera images (36 infants 1 to 24 months) provide strong support for the Face-input hypothesis. The results suggest developmental constraints on the environment that ensure faces are prevalent early in development.

Infants rapidly detect human faces in complex naturalistic visual scenes

“…We propose that our stimuli can account for the lack of early bias reported previously. Specifically, we assert that the naturalistic scenes we used provided a closer approximation of the infant's real‐world visual experiences (see Jayaraman et al, for examples of infant head‐camera mounted stills) than visual grid/array displays used previously (cf. Di Giorgio et al, ; Gliga et al, ; Gluckman & Johnson, ; Jakobsen et al, ) and helped to facilitate detection.…”

“…Although these findings provide insight into infant face detection, faces are rarely viewed in isolation in non‐laboratory conditions, they are never seen embedded within an array (circular or grid) nor are they seen at a constant distance. Instead, recent studies using head‐mounted camera recording methods have confirmed that faces are typically viewed alongside substantial levels of competing visual information and at myriad distances (Jayaraman, Fausey, & Smith, ; Sugden, Mohamed‐Ali, & Moulson, ). Consequently, the utility of artificial presentations and the generalizability of findings from existing work is unclear.…”

The impact of negative affect on attention patterns to threat across the first 2 years of life.

“…Jayaraman, Fausey, and Smith (2017) found that the frequency of faces in an infant's field of view decreases in the first two years of life. Thus, the time gazing at faces in view drops from 14 minutes/hour at 3 months to 5 minutes/hour at 18 months, even though their access to people did not decrease.…”

The functions of imitative behaviour in humans

“…Instead, it has been suggested that infants learn SMCs for facial actions from seeing other people's imitative actions (Ray & Heyes, 2011), and data on infant-parent behaviour support this possibility. Several developmental studies indicate that infants are born with a predisposition toward face-related stimuli (Farroni et al, 2005) and gain ample experience in viewing faces (Jayaraman, Fausey & Smith, 2017). More critically, parents have a tendency to mimic their infants, on average, once every minute (Jones, 2009).…”