The Affects of Distortion

Abstract

Purpose : Affect and face identification are critical activities of daily living that may be impaired by blur or distortions caused by vision loss and in disorders such as autism, prosopagnosia, and prosopometamorphopsia. Distortions alter the spatial relationships among facial features, disrupting configural information. To examine configural information in face processing, we measure how the spatial scale and amplitude of distortions influence the identification of affect and identity.

Methods : Bandpass filtered noise (Fpeak@1-32 cycles/face) was used to generate pixel shifts to distort faces from the IASLab database. The amplitude of distortion was varied using an adaptive staircase. 8 normally-sighted subjects were given unlimited time to identify which of 4 distorted faces (within 6.5°x9.8°ellipses in a 2x2 grid) matched a word representing 1 of 8 universal emotions: sad, excited, happy, fear, calm, anger, or disgust (affect task) or matched the identity of an undistorted face (ID task). Image cues were removed from each face by equalizing the luminance distribution and chrominance to the average face.

Results : Repeated measures ANOVA showed that observers could tolerate significantly more distortion for face rather than affect identification (F_1,35=13.3;p=.0083). There was a significant effect of distortion spatial scale (F_5,35=6.6;p=.0002) and face inversion (F_1,35=14.0;p=.0073) on affect identification, with no interaction between these factors (F_5,35=1.4;p=.2504). There was a significant interaction between distortion scale and inversion for face identification (F_5,35=4.5;p=.003) such that distortions at coarse and fine scales mediated a face inversion effect, but not when distortions were applied at the middle critical scales (4-16 cycles/face).

Conclusions : These results suggest that the face inversion effect for distortion is present in both affect and face identification, while differences in their spatial tuning imply differences in how our brains process the identity of the face compared to its emotion. This may inform future studies with vision-loss patients and neurodivergent individuals to better understand the impact of their disorder on facial identification and emotion recognition and differentiate potential sites of face processing impairment.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.