How do autism spectrum disorders process human face? A meta-analysis of eye-tracking studies
2018, 26 (1):
Aberrant eye gaze is one of important indicators for autism spectrum disorders (ASD) according to previous studies. Recent eye tracking studies yield inconsistent findings on whether ASD may pay less attention towards the mouth region compared with typical development (TD) participants. In this study, a meta-analysis is conducted with fixation durations on both eyes and mouth regions as dependent variables. Twenty-seven eligible ASD eye-tracking studies were included in the current study. As a result, 43 independent effect sizes containing 1,343 participants are computed in the eye-related meta-analysis, and 36 independent effect sizes containing 1,112 participants in the mouth-related meta-analysis are analyzed. The results revealed that individuals with ASD fixated significantly shorter on the eye region than the TD (d = −0.75). However, no significant difference was found on fixation duration of the mouth region between two groups (d = −0.29). The moderator analysis indicated that age (d children = −0.89, d adult = −0.04) and face inversion (d upright = −0.79, d inverted = 0.31) moderated eye-related fixation duration. In addition, age (d children = 0.40, d adult = −0.56), verbal IQ (d match = 0.63, d no match = −0.62), nonverbal IQ (d match = 0.27, d no match= −0.51), the severity of autism (d high function = 0.43, d low function = −0.65), and task types (d free view = −0.48, d discrimination task = 0.90) moderated the effect of experimental manipulation on the mouth-related fixation duration. These findings suggest that fixation duration on the eye region is a potential indicator of ASD but the mouth region may not be.
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