Dissociated overt and covert recognition as an emergent property of a lesioned neural network.

Covert recognition of faces in prosopagnosia, in which patients cannot overtly recognize faces but nevertheless manifest recognition when tested in certain indirect ways, has been interpreted as the functioning of an intact visual face recognition system deprived of access to other brain systems necessary for consciousness. The authors propose an alternative hypothesis: that the visual face recognition system is damaged but not obliterated in these patients and that damaged neural networks will manifest their residual knowledge in just the kinds of tasks used to measure covert recognition. To test this, a simple model of face recognition is lesioned in the parts of the model corresponding to visual processing. The model demonstrates covert recognition in 3 qualitatively different tasks. Implications for the nature of prosopagnosia, and for other types of dissociations between conscious and unconscious perception, are discussed.

[1]  R. Bauer,et al.  Autonomic recognition of names and faces in prosopagnosia: A neuropsychological application of the guilty knowledge test , 1984, Neuropsychologia.

[2]  M. Posner.  Chronometric explorations of mind , 1978 .

[3]  James L. McClelland,et al.  An interactive activation model of context effects in letter perception: I. An account of basic findings. , 1981 .

[4]  E. Haan,et al.  Behavioural and Physiological Evidence for Covert Face Recognition in a Prosopagnosic Patient , 1992, Cortex.

[5]  R A Johnston,et al.  Understanding face recognition with an interactive activation model. , 1990, British journal of psychology.

[6]  L. Weiskrantz,et al.  Thought Without Language , 1988 .

[7]  R. Bauer.  The Cognitive Psychophysiology of Prosopagnosia , 1986 .

[8]  James L. McClelland,et al.  Parallel distributed processing: explorations in the microstructure of cognition, vol. 1: foundations , 1986 .

[9]  A W Young,et al.  Naming and Categorizing Faces and Written Names , 1986, The Quarterly journal of experimental psychology. A, Human experimental psychology.

[10]  A. Young,et al.  Understanding covert recognition , 1991, Cognition.

[11]  D. Dennett,et al.  The Nature of Consciousness , 2006 .

[12]  P. Feyereisen,et al.  A case of prosopagnosia with some preserved covert remembrance of familiar faces , 1983, Brain and Cognition.

[13]  A. Damasio,et al.  Knowledge without awareness: an autonomic index of facial recognition by prosopagnosics. , 1985, Science.

[14]  Carsten Peterson,et al.  A Mean Field Theory Learning Algorithm for Neural Networks , 1987, Complex Syst..

[15]  A Cohen,et al.  Extrageniculate vision in hemianopic humans: saccade inhibition by signals in the blind field. , 1990, Science.

[16]  Geoffrey E. Hinton,et al.  Distributed Representations , 1986, The Philosophy of Artificial Intelligence.

[17]  Geoffrey E. Hinton,et al.  Lesioning an attractor network: investigations of acquired dyslexia , 1991 .

[18]  Geoffrey E. Hinton,et al.  Learning and relearning in Boltzmann machines , 1986 .

[19]  A. Young,et al.  Faces Interfere with Name Classification in a Prosopagnosic Patient , 1987, Cortex.

[20]  R. Bauer,et al.  Implicit learning of new faces in prosopagnosia: An application of the mere-exposure paradigm , 1990, Neuropsychologia.

[21]  Raymond Bruyer,et al.  Covert face recognition in prosopagnosia: A review , 1991, Brain and Cognition.

[22]  A. Damasio,et al.  Non-conscious face recognition in patients with face agnosia , 1988, Behavioural Brain Research.

[23]  A. Young,et al.  Prosopagnosia and object agnosia without covert recognition , 1989, Neuropsychologia.

[24]  A. Young,et al.  Face recognition without awareness , 1987 .

[25]  Anthony J. Marcel,et al.  Consciousness in Contemporary Science , 1992 .

[26]  A. Young,et al.  The faces that launched a thousand slips: everyday difficulties and errors in recognizing people. , 1985, British journal of psychology.

[27]  Javier R. Movellan,et al.  Contrastive Hebbian Learning in the Continuous Hopfield Model , 1991 .

[28]  J. Sergent,et al.  Prosopagnosia in a right hemispherectomized patient. , 1989, Brain : a journal of neurology.

[29]  K. Cave,et al.  Can We Lose Memories of Faces? Content Specificity and Awareness in a Prosopagnosic , 1991, Journal of Cognitive Neuroscience.

[30]  A. Young,et al.  Aspects of face processing , 1986 .

[31]  James L. McClelland,et al.  A distributed, developmental model of word recognition and naming. , 1989, Psychological review.

[32]  L. Squire.  The neuropsychology of human memory. , 1982, Annual review of neuroscience.

[33]  Richard Latto,et al.  Is blindsight an effect of scattered light, spared cortex, and near-threshold vision? , 1983, Behavioral and Brain Sciences.

[34]  Tim Shallice,et al.  Lexical processing in the absence of explicit word identification: Evidence from a letter-by-letter reader , 1986 .

[35]  Geoffrey E. Hinton.  Using fast weights to deblur old memories , 1987 .

[36]  Bruno Debruille,et al.  Brain potentials reveal covert facial recognition in prosopagnosia , 1989, Neuropsychologia.

[37]  L Weiskrantz,et al.  The Ferrier Lecture, 1989 - Outlooks for blindsight: explicit methodologies for implicit processes , 1990, Proceedings of the Royal Society of London. B. Biological Sciences.