Sex differences of hemispheric lateralization for faces and Chinese characters in early perceptual processing.

Previous event-related potential studies showed that the N170 response is left-lateralized for words and right-lateralized for faces. Using a one-back repetition task, this study aimed to clarify sex differences in hemispheric specialization for both faces and words in early visual processing. We found that the N170 amplitude elicited by faces in males was right-lateralized, while in females it was bilateral. Interestingly, the N170 amplitude elicited by Chinese characters in males was bilateral, whereas in females it was left-lateralized. The N170 latency for faces was shorter in females than in males, whereas the N170 latency for Chinese characters was similar in females and males. The degree of lateralization of faces was significantly related to the degree of lateralization of Chinese characters in both the female and male groups. Therefore, sex differences in N170 hemispheric lateralization for faces are different from those for Chinese characters, and there are some links between the two categories of objects of expertise in early perceptual processing.