Dynamic Eye Tracking Based Metrics for Infant Gaze Patterns in the Face-Distractor Competition Paradigm

Abstract

ObjectiveTo develop new standardized eye tracking based measures and metrics for infants’ gaze dynamics in the face-distractor competition paradigm.MethodEye tracking data were collected from two samples of healthy 7-month-old (total n = 45), as well as one sample of 5-month-old infants (n = 22) in a paradigm with a picture of a face or a non-face pattern as a central stimulus, and a geometric shape as a lateral stimulus. The data were analyzed by using conventional measures of infants’ initial disengagement from the central to the lateral stimulus (i.e., saccadic reaction time and probability) and, additionally, novel measures reflecting infants gaze dynamics after the initial disengagement (i.e., cumulative allocation of attention to the central vs. peripheral stimulus).ResultsThe results showed that the initial saccade away from the centrally presented stimulus is followed by a rapid re-engagement of attention with the central stimulus, leading to cumulative preference for the central stimulus over the lateral stimulus over time. This pattern tended to be stronger for salient facial expressions as compared to non-face patterns, was replicable across two independent samples of 7-month-old infants, and differentiated between 7 and 5 month-old infants.ConclusionThe results suggest that eye tracking based assessments of infants’ cumulative preference for faces over time can be readily parameterized and standardized, and may provide valuable techniques for future studies examining normative developmental changes in preference for social signals.SignificanceStandardized measures of early developing face preferences may have potential to become surrogate biomarkers of neurocognitive and social development.

A Method to Quantify Visual Information Processing in Children Using Eye Tracking

“…Several studies have shown the value of remote eye tracking in vulnerable populations of children, to infer attentional or psychological capacities 9,12,18 . Whereas most studies rely on behavioral observations and the use of instructions, a distinct feature of the current paradigm is the nonverbal, quantitative approach.…”

“…This information is obtained by calculating quantitative parameters based on temporal and spatial properties of eye movement responses. Examples of such parameters are reaction time 13 , fixation time 17 , saccade metrics 7 or cumulative attention allocation 18 . The availability of these parameters is new to the field of visual assessment in children at a young developmental stage.…”

Evidence for spared attention to faces in 7-month-old infants after prenatal exposure to antiepileptic drugs

“…The eye-tracking test was designed to assess infants' attention to nonface patterns and faces by using a face-distractor competition paradigm [31,40]. In this paradigm, infants fixate a nonface pattern or a picture of a face in the center of the screen while a lateral distractor stimulus (geometric shape) is presented to the left or to the right.…”

“…Before running the actual study protocol, a calibration procedure was performed as explained in detail by Ahtola et al [31]. The eye-tracking protocol constituted 32 trials.…”

“…Recent developments in eye-tracking-based testing of infant cognition [28][29][30] have opened new possibilities for automated testing of infants' visual acuity, visuospatial orienting (gaze shifts to a novel visual stimulus), and attention to salient social stimuli, such as faces [31][32][33][34][35]. These processes provide the key "building blocks" of later emerging advanced cognitive, academic, and social skills [36,37].…”