Impaired rapid neural face categorization after reversing long-lasting congenital blindness

Transient early visual deprivation in humans impairs the processing of faces more than of other object categories. While configural face processing and face individuation appear to be largely impaired in sight recovery individuals following congenital visual deprivation, their behavioral ability to categorize stimuli as faces has been described as preserved. Here we thoroughly investigated rapid automatic face categorization in individuals who had recovered sight after congenital blindness. Eighteen participants (6 women, 12 men) who had undergone congenital cataract reversal surgery participated in a well-validated electroencephalographic (EEG) experiment with fast periodic visual stimulation (FPVS) to elicit automatic neural face-categorization responses from variable natural images. As normally sighted controls (N = 13) and individuals with reversed developmental cataracts (N = 16), congenital cataract reversal individuals exhibited clear neural face-categorization activity. However, their neural face categorization responses were significantly weaker and delayed. These observations show that previous behavioral studies with explicit tasks lacked sensitivity to uncover altered face categorization in sight-recovery individuals with a history of congenital cataracts. This indicates that early experience is necessary for categorization too. We speculate that altered neural correlates of face categorization result from a lower selectivity of face-selective areas of the ventral occipito-temporal cortex, impeding higher-order face processes such as face identity recognition.