A theory of the brain - the brain uses both distributed and localist (symbolic) representation

The issue of whether objects and concepts are represented in the brain by single neurons or multiple ones, where the multiple ones are conceived to represent subconcepts or microfeatures, has plagued brain-related sciences for decades, spawning different scientific fields such as artificial intelligence (AI) and connectionism. It is also a source of dispute within some of these scientific fields. In connectionism, for example, there is never ending debate between the theories of localist (in a sense symbolic) and distributed representation. To resolve this conflict, we analyze a highly publicized class of models used by connectionists (distributed representation theorists) for complex cognitive processes and show that, contrary to their claim, they actually depend on localist (symbolic) representation of higher-level concepts in these models. We also find that these connectionist models use processes similar to symbolic computation. Based on this analysis and the accumulating evidence from single-unit recordings in neurophysiology that shows that single cells can indeed encode information about single objects (e.g. a Jennifer Aniston cell in our brains), we propose the theory that the brain uses both forms of representation, localist and distributed, and that both forms may be necessary, depending on the context. Our other conjecture is that the brain uses both forms of computation, symbolic and distributed (parallel). This theory should finally resolve the decades long conflict about representation and computational processes that has generated divisions within our fields and has stalled our progress towards creating brain-like learning systems.

[1]  Philipp Slusallek,et al.  Introduction to real-time ray tracing , 2005, SIGGRAPH Courses.

[2]  C. Gross Genealogy of the “Grandmother Cell” , 2002, The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry.

[3]  Peter M. Todd,et al.  Learning and connectionist representations , 1993 .

[4]  C. Koch,et al.  Explicit Encoding of Multimodal Percepts by Single Neurons in the Human Brain , 2009, Current Biology.

[5]  Abraham J Susswein,et al.  Comparative neuroethology of feeding control in molluscs. , 2002, The Journal of experimental biology.

[6]  W. Bialek,et al.  RELIABILITY AND STATISTICAL EFFICIENCY OF A BLOWFLY MOVEMENT-SENSITIVE NEURON , 1995 .

[7]  M. Ross Quillian,et al.  Retrieval time from semantic memory , 1969 .

[8]  M. Page,et al.  Connectionist modelling in psychology: A localist manifesto , 2000, Behavioral and Brain Sciences.

[9]  James L. McClelland,et al.  Semantic Cognition: A Parallel Distributed Processing Approach , 2004 .

[10]  J. Fodor,et al.  Connectionism and cognitive architecture: A critical analysis , 1988, Cognition.

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

[12]  James L. McClelland,et al.  Locating object knowledge in the brain: comment on Bowers's (2009) attempt to revive the grandmother cell hypothesis. , 2010, Psychological review.

[13]  C. Koch,et al.  Invariant visual representation by single neurons in the human brain , 2005, Nature.

[14]  Jeffrey S Bowers,et al.  On the biological plausibility of grandmother cells: implications for neural network theories in psychology and neuroscience. , 2009, Psychological review.

[15]  H B Barlow,et al.  Single units and sensation: a neuron doctrine for perceptual psychology? , 1972, Perception.

[16]  Allen Newell,et al.  Computer science as empirical inquiry: symbols and search , 1976, CACM.

[17]  P. Smolensky THE CONSTITUENT STRUCTURE OF CONNECTIONIST MENTAL STATES: A REPLY TO FODOR AND PYLYSHYN , 2010 .

[18]  C. Koch,et al.  Multiplicative computation in a visual neuron sensitive to looming , 2002, Nature.

[19]  James L. McClelland,et al.  Précis of Semantic Cognition: A Parallel Distributed Processing Approach , 2008, Behavioral and Brain Sciences.

[20]  Asim Roy,et al.  Connectionism, Controllers, and a Brain Theory , 2008, IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans.

[21]  Allen Newell,et al.  Physical Symbol Systems , 1980, Cogn. Sci..

[22]  H. Barlow The neuron doctrine in perception. , 1995 .

[23]  Geoffrey E. Hinton,et al.  Learning representations by back-propagating errors , 1986, Nature.

[24]  P. Smolensky On the proper treatment of connectionism , 1988, Behavioral and Brain Sciences.

[25]  Jeffrey S Bowers,et al.  More on grandmother cells and the biological implausibility of PDP models of cognition: a reply to Plaut and McClelland (2010) and Quian Quiroga and Kreiman (2010). , 2010, Psychological review.

[26]  G. Kreiman,et al.  Measuring sparseness in the brain: comment on Bowers (2009). , 2010, Psychological review.