Face and gaze processing in the broader autism phenotype: independent differences in ASD relatives

Background: Our previous research in adults with an Autism Spectrum Disorder (ASD) suggests that ASD face processing differences fall into two categories: face perception and making judgements about eye stimuli. Previous studies have also reported deficits on ‘higher level’ face tasks that are believed to tap Theory of Mind.  Relatives of individuals with ASD frequently show a 'broader autism phenotype', but the exact pattern of their face processing differences is still unclear.

Objectives: This study aimed to examine the relationship between performance on face and eye-gaze tasks in the broader autism phenotype, including a Theory of Mind face test, and so investigate whether these tasks are tapping separate skills.

Methods: Sixty-seven UK parents and siblings without an ASD were tested as part of the IMGSAC study.  All participants were assessed on the Benton Facial Recognition Test (BFRT), a task of discriminating pairs of faces or houses, the 'Reading the Mind in the Eyes' Test, and judging eye-gaze direction at brief exposure durations.

Results: Performance on the Reading the Mind in the Eyes Test was significantly positively correlated with accuracy at detecting the direction of briefly presented averted eyes in faces.  BFRT scores were positively correlated with sensitivity to face differences in the faces/houses task.  These correlations remained strong after controlling for both verbal and performance IQ, and despite high correlations within these pairs of tasks, there were no correlations between the pairs.

Conclusions: The Reading the Mind in the Eyes Test paired with the eye-gaze task, and the BFRT paired with the facial discrimination task, appear to tap individual variation in two separate mechanisms: Face discrimination and a separate eye-gaze system. Our future research will explore the relationship between severity of the broader autism phenotype and performance on tasks that assess these two face processing mechanisms.