Abstract
Preference and gaze interact in a positive feedback loop to produce a phenomenon known as the ‘gaze cascade’ effect. In the few seconds before a decision is made, a gaze bias occurs toward the stimulus that is eventually chosen. This gaze cascade is especially robust in tasks that involve face preference decisions. Autism is a pervasive developmental disorder where deficits in evaluating and making social judgments about faces occur. Persons with autism typically have inattention to faces and direct gaze aversion. The present study was set up to examine whether these known aberrations in visual face processing interfere with preference choice decision making in ASD, reflected in a deviant gaze cascade pattern.
4 ASD subjects and 3 age and gender matched healthy controls (HC) performed a 2-alternative forced-choice task, while their eye-gaze was tracked. Their task was to select the stimulus they prefer by pressing a button under a free viewing condition. Stimulus types consisted of faces and natural scenes.
First, we were able to replicate the findings of a gaze cascade in the HCs, already with this temporary group size. Interestingly, the known gaze aversion for faces in ASD did not interfere with the gaze bias toward the to-be-chosen picture at decision time, independent of stimulus type. Indeed, the probability of a gaze bias towards the chosen picture at 40 ms before response was even significantly higher in the autism group than in the HCs (p < 0.001 for each of the conditions). On the other hand, the course of their viewing patterns clearly deviated from that of the HCs and is not in agreement with the typical gaze cascade. These findings implicate that while gaze is clearly involved in preference formation in autistic subjects, the psychological process that leads to the decision may differ from that of HCs.
JST CREST, Tamagawa Caltech GCOE.