Perceptual effects of fast and automatic visual ensemble statistics from faces in individuals with typical development and autism spectrum conditions.

We investigated whether covert ensembles of high- (emotion), and low-level (brightness) visual information, extracted from peripheral faces (presentation/encoding:200 ms), unintentionally influences perception of a central target face stimulus in individuals typically developing (TD) and with autism spectrum condition (ASC). Graded alterations in the summary intensities of the emotion and brightness of the peripheral stimuli modulated the perceptions of the target face in both TD and ASC. In contrast, when we measured goal-directed (overt) ensemble face- emotion and brightness perception, we found that in half of ASC the overt ensemble emotion perception was impaired than TD. Additionally, we repeated both experiments with a backward visual mask to restrict not just encoding but also background processing in the visual system to 200 ms. This revealed that the effect of peripheral ensembles on centre perception was present only with brightness at least in TD but of overt ensembles was evident with both emotion and brightness in TD and ASC alike. These results suggest that while ensemble statistics of low-level information derived automatically and rapidly (200 ms) from contextualized faces are used for target face perception, the same takes longer with high-level information. However, overt facial ensembles are rapidly processed in both TD and ASC.