The eyes have it: visual pop‐out in infants and adults

Abstract

Visual search studies with adults have shown that stimuli that contain a unique perceptual feature pop out from dissimilar distractors and are unaffected by the number of distractors. Studies with very young infants have suggested that they too might exhibit pop-out. However, infant studies have used paradigms in which pop-out is measured in seconds or minutes, whereas in adults pop-out occurs in milliseconds. In addition, with the previous infant paradigms the effects from higher cognitive processes such as memory cannot be separated from pop-out and selective attention. Consequently, whether infants exhibit the phenomenon of pop-out and have selective attention mechanisms as found in adults is not clear. This study was an initial attempt to design a paradigm that would provide a comparable measure between infants and adults, thereby allowing a more accurate determination of the developmental course of pop-out and selective attention mechanisms. To this end, we measured 3-month-olds' and adults' saccade latencies to visual arrays that contained either a + among Ls (target-present) or all Ls (target-absent) with set sizes of 1, 3, 5 or 8 items. In Experiment 1, infants' saccade latencies remained unchanged in the target-present conditions as set size increased, whereas their saccade latencies increased linearly in the target-absent conditions as set size increased. In Experiment 2, adults' saccade latencies in the target-present and target-absent conditions showed the same pattern as the infants. The only difference between the infants and adults was that the infants' saccade latencies were slower in every condition. These results indicate that infants do exhibit pop-out on a millisecond scale, that it is unaffected by the number of distractors, and likely have similar functioning selective attention mechanisms. Moreover, the results indicate that eye movement latencies are a more comparable and accurate measure for assessing the phenomenon of pop-out and underlying attentional mechanisms in infants.

Toward Early Markers for Autism Spectrum Disorder Using Eye Tracking

“…When search for a target is una↵ected by the number of nontargets, it may be noted as visual pop-out or e cient (Wolfe, 1998a). Adler & Orprecio (2006) consequently conclude that visual pop-out is present in infancy. Adler & Gallego (2014) extend this by reporting that infants exhibit e cient search for feature-present but not for feature-absent visual search trials.…”

“…Colombo et al (1995); Quinn & Bhatt (1998) claimed that visual pop-out was present in infancy, based on this asymmetry in preferentially looking at feature-present but not feature-absent stimuli. However, Adler & Orprecio (2006) argued that this could not be concluded on the basis of preferential looking times, which are typically on the order of several seconds, while visual pop-out or e cient search occurs on the order of several hundreds of milliseconds. They argued that knowledge of the eye movements was needed in order to draw this conclusion.…”

“…They argued that knowledge of the eye movements was needed in order to draw this conclusion. In their study, Adler & Orprecio (2006) measured saccade latencies of 3 month-old infants to a target and report that saccade latency was una↵ected by the number of non-targets. When search for a target is una↵ected by the number of nontargets, it may be noted as visual pop-out or e cient (Wolfe, 1998a).…”

Differential attentional responding in caesarean versus vaginally delivered infants

“…Furthermore, the criteria for determining valid and useable eye movements were identical to those used in Experiment 1, with one exception. In the present experiment, only the data of infants (n = 12) who attended (looked at the stimuli) on a minimum of 60 % of the trials, instead of 50 % as in Experiment 1, were included (Adler & Haith, 2003;Adler & Orprecio, 2006). The minimum attention criterion was set higher for the expectation experiment in order to assure that the infants included in the data analysis had enough exposure to the stimuli and were given enough time to acquire important predictable information about the stimuli.…”

“…This was assessed through the infant's scan path in conjunction with the stimulus location. The 50 % criterion has been used in previous studies based on infants' eye movements (Adler & Haith, 2003;Adler & Orprecio, 2006) and is typically taken as an indication that the eye movement is intentional and not random.…”