DISSOCIATED OVERT AND COVERT RECOGNITION AS AN EMERGENT PROPERTY OF ALESIONED NEURAL-NETWORK

Covert recognition of faces in prosopagnosia, in which patients cannot overtly recognize faces but nevertheless manifest recognition when te sted in certain indirect ways, has been interpreted as the functioning of an intact visual face recognition system deprived of access to oth er brain systems necessary for consciousness. The authors propose an a lternative hypothesis: that the visual face recognition system is dama ged but not obliterated in these patients and that damaged neural netw orks will manifest their residual knowledge in just the kinds of tasks used to measure covert recognition. To test this, a simple model of f ace recognition is lesioned in the parts of the model corresponding to visual processing, The model demonstrates covert recognition in 3 qua litatively different tasks, Implications for the nature of prosopagnos ia, and for other types of dissociations between conscious and unconsc ious perception, are discussed.