Foundations Of Cognitive Science

Cell Assembly

James’s (1890) law of habit was central to the basic mechanism proposed by neuroscientist Donald Hebb for the development of cell assemblies (Hebb, 1949).  A cell assembly is a system of interconnected neurons that activates in a specific dynamic pattern; activation of part of the cell assembly sends signals that activate the remainder of its components.  Hebb provided a famous modern statement of James’ law of habit:  “When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased” (p. 62).  This makes explicit the modern connectionist idea that learning is modifying the strength of connections between processors.  Hebb’s theory inspired the earliest computer simulations of memory systems akin to the one proposed by James (Milner, 1957; Rochester, Holland, Haibt, & Duda, 1956).  These simulations revealed a critical role for inhibition that led Hebb to revise his theory (Hebb, 1959).


  1. Hebb, D. O. (1949). The Organization Of Behaviour. New York: John Wiley and Sons.
  2. Hebb, D. O. (1959). A neuropsychological theory. In S. Koch (Ed.), Psychology: A Study Of A Science.  Volume1: Sensory, Perceptual, And Physiological Foundations (pp. 622-643). New York, NY: McGraw-Hill.
  3. James, W. (1890). The Principles Of Psychology, Volume One. New York, NY: Dover Publications.
  4. Milner, P. M. (1957). The cell assembly: Mark II. Psychological Review, 64(4), 242-252.
  5. Rochester, N., Holland, J. H., Haibt, L. H., & Duda, W. L. (1956). Tests on a cell assembly theory of the action of the brain, using a large digital computer. IRE Transactions On Information Theory, IT-2, 80-93.

(Added April 2011)