Face and object visual processing linked to literacy: a longitudinal study

Abstract

Reading is a cultural invention too recent to involve dedicated genetic or developmental mechanisms. It has been proposed that reading partly recycles pre-existing brain systems (neural recycling hypothesis, Dehaene, 2004). This hypothesis is supported by fMRI studies. Reading acquisition does not only lead to the development of a strong response to written materials in the left fusiform gyrus, the "visual word form area" (VWFA, Cohen et al., 2000; Dehaene & Cohen, 2011), but also reorganizes the ventral visual system: it competes with the cortical representation of other visual objects, especially faces, with less left and more right fusiform activation to faces in literates compared to illiterates (Dehaene et al., 2010). However, little is known about the behavioural consequences of this brain reorganization. How is face processing affected by literacy? One possibility could be that the stronger right-hemispheric lateralization for face processing in literates implies more holistic processing of faces. Alternatively, literacy may lead to a dynamic and flexible tuning of face processing (Harris & Aguirre, 2010). As a result, the depth with which a face is holistically encoded could depend on the nature of the task (Gao, Flevaris, Robertson & Bentin, 2011). To examine these possibilities, nine adult illiterate females participated in a longitudinal study in which they were offered an intensive alphabetization course for three months. Meanwhile, the evolution of reading skills as well as their memory for and sensitivity to configural vs. local properties of faces (and other objects) was measured. Participants were tested five times: two times before starting the literacy classes (pre-tests), two during the literacy classes, and finally after they completed the course. Results will be presented at the conference.