Eye contact detection in humans from birth

Abstract

Making eye contact is the most powerful mode of establishing a communicative link between humans. During their first year of life, infants learn rapidly that the looking behaviors of others conveys significant information. Two experiments were carried out to demonstrate special sensitivity to direct eye contact from birth. The first experiment tested the ability of 2- to 5-day-old newborns to discriminate between direct and averted gaze. In the second experiment, we measured 4-month-old infants' brain electric activity to assess neural processing of faces when accompanied by direct (as opposed to averted) eye gaze. The results show that, from birth, human infants prefer to look at faces that engage them in mutual gaze and that, from an early age, healthy babies show enhanced neural processing of direct gaze. The exceptionally early sensitivity to mutual gaze demonstrated in these studies is arguably the major foundation for the later development of social skills.

Figure 1

Experimental stimuli. (a) Stimuli in both experiments were color photographic images of female faces directing their gaze straight-on to the viewers (Direct Gaze) or averted to one side (Averted Gaze). (b) Low-pass filtered versions of the stimuli illustrate the estimated resolution of the images in the visual system according to newborns' average visual acuity (19). Measures in the figure indicate viewing angles of faces and eyes when fixated or when in the periphery (in brackets). (c) These pictures illustrate the estimated resolution of the images according to 4-month-old infants' average visual acuity (19).

Figure 2

Results of the preferential looking study with newborns. (a) Mean looking times (and SE) spent at the two stimulus types. Newborns spent significantly more time looking at the face with mutual gaze than looking at the face with averted gaze. (b) Mean number of orientations toward each type of stimulus. (c) Filled triangles indicate reference scores for the direct gaze over the averted gaze for each individual newborn. Open triangles indicate average preference scores.

Figure 3

ERPs recorded to faces with direct and averted gaze in 4-month-old infants. (a) All but one of the electrodes over the occipital cortex recorded an enhanced N170 response (peaking at 240 ms after stimulus) to the faces with direct gaze compared with the faces with averted gaze. (b) ERPs to the two kinds of stimuli averaged across all occipital electrode sites. (c) Spherical spline interpolations (22) for the surface distributions of the average amplitude at 240-ms latency show an enhanced medial occipital response to mutual gaze compared with averted gaze. White spots mark the electrode locations used in the statistical analyses.