Abstract
The typically developing (TD) population shows perceptual and physiological differences (global/local perception, motion coherence, flicker fusion, magnocellular function) in the typically developing (TD) population related to the degree of autistic traits. However, some have questioned whether Baron-Cohen's AQ is tapping clinical ASD, where children with autism show precocious skill in visual search, as well as differences in global/local visual perception. Here, we measured visual search and cross orientation surround suppression (COSS) in18 young adults (20-29 yr) of mixed sex. They completed a Chinese translation of the AQ (English form alongside). In the search task (present/absent 2AFC), a 2x2 array of parallel line segments was embedded in an array (9, 16, 36, 81, 169, 400 elements) of randomly oriented lines. In the COSS task, one of four annular segments containing gratings would appear with less contrast than the others. The neighbouring regions were either parallel or perpendicular in orientation. Just noticeable difference thresholds were obtained for low (.5 cycles per degree) and high (3.0 cycles per degree) spatial frequency gratings. The suppression index showed significant negative correlation with AQ score (RSquare(18) =0.27, p=.0267) for the HSF task, but not for the LSF task (RSquare(18) =0.009, p>0.7). For the visual search task, reasonable RT/set size linearity was observed except for the largest set which was excluded from analysis. Statistical comparison of linear fits showed no significant correlation between reaction times slope per item and AQ score, whether for target present (RSquare(18) =0.0067, p=.75) or target absent trials (RSquare(18) =0.057, p=.337). It is possible that the two tasks tap different neural systems. Social disorganization common to those with high AQ and schizotypal personality (SPQ) scores, potentially links to clinical findings in schizophrenia, where reduced COSS and reduced GABA concentration in visual cortex form markers of reduced inhibition.
Meeting abstract presented at VSS 2017