Abstract
A recent theoretical account (Behrmann & Plaut, 2011, 2015) and associated empirical data (Dundas et al., 2013) argues for the interdependence of the development of hemispheric organization for words with that of faces in typically developing children. Specifically, the claim is that, during the course of acquiring word recognition skills, the pressure to couple visual and language representations in the left hemisphere (LH) results in competition for representation of faces, and these latter representations become largely lateralized in the right hemisphere (RH). This account makes a specific prediction with regard to atypical development and that is that typical hemispheric organization for words can develop in the context of atypical development of face processing but not vice versa, and the latter prediction is upheld in recent findings from individuals with developmental dyslexia. We explore the first prediction using a visual hemifield presentation paradigm with words and faces, with concurrent ERP measurement, in a group of adults with congenital prosopagnosia (CP), a lifelong impairment in face recognition, and typically developed controls. In contrast with the controls, the CP group failed to produce the dominant RH response for faces, with equal magnitude N170 components elicited by faces and words. Both the controls and the CP adults, however, produced a dominant LH response for words, with greater N170 component in response to words than to faces. Differences between the groups in hemispheric organization were specific to the N170 and were not found in the P100 component. These findings are consistent with the account that typical hemispheric organization for words can develop in the absence of typical hemispheric organization for faces. Additionally, when considered with evidence from developmental dyslexia, the results here support the directionality of interdependent hemispheric development and the hypothesis that hemispheric organization for words may precede that for faces.
Meeting abstract presented at VSS 2016