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Lashley, Karl

Summary Article: Lashley, Karl Spencer from Biographical Dictionary of Psychology

Born: 1890, Davis, USA Died: 1958, Poitiers, France Nat: American Ints: Experimental analysis of behaviour, physiological and comparative, clinical neuropsychology Educ: BA University of West Virginia, 1901; MS University of Pittsburgh, 1911; PhD Johns Hopkins University. 1914 Appts & awards: Research Professor in Neuropsychology, Harvard University; President, APA, 1929; Hon. DSc, University of Pittsburgh, 1936, University, of Chicago, 1941, Western Reserve University, 1951, University of Pennsylvania; Warren Medal in Psychology, 1937; President, Eastern Psychological Association, 1938; Hon. MA, Harvard University, 1942; Elliot Medal in Zoology, 1943; Baly Medal in Physiology, 1953; Hon LLD, Johns Hopkins University, 1953


Principal publications
  • 1921 Studies of cerebral function in learning: III. The motor areas. Brain, 44, 255-86.
  • 1929 Brain Mechanism and Intelligence: A Quantitative Study of Injuries to the Brain. University of Chicago Press.
  • 1930 Basic neural mechanism in behavior Psychological Review, 1-24.
  • 1934 The mechanism of vision: VIII. The projection of the retina upon the cerebral cortex of the rat. Journal of Comparative Neurology, 60, 57-79.
  • 1941 Thalamo-cortical connections of the rat's brain. Journal of Comparative Neurology, 75, 67-121.
  • 1942 The problem of cerebral organisation in vision. Biological Symposia, 7, 301-22.
  • 1946 The cytoarchitecture of the cerebral cortex of Ateles: A critical examination of architechtonic studies. Journal of Comparative Neurology, 85, 233-302.
  • 1958 Cerebral organisation and behavior. In The Brain and Human Behavior: Proceedings of the Association for Research in Nervous and Mental Disease. Williams and Wilkin.
  • Further reading
  • Dewsbury, D. A. (1993) Contributions to the history of psychology: XCIV. The boys of summer at the end of summer: The Watson-Lashley correspondence of the 1950s. Psychological Reports, 72, 263-69.
  • Furchtgott, E. (1995) A tribute to Lashley. American Psychologist, 50, 178-9.
  • Weidman, N. (1994) Mental testing and machine intelligence: The Lashley—Hull debate. Journal of the History of the Behavioral Sciences, 30, 162-80.

  • Lashley's major work was in the area of brain function and learning, using learning and discrimination tasks to study the effects of ablation at sites in the rat's brain. His academic training was originally in zoology, but he became interested in psychology while researching for his doctorate. He worked with J.B. Watson and was strongly influenced by the behavouristic approach. During his postdoctoral period he started to work with S.I. Franz at St Elizabeth's Hospital, Washington DC. He studied some neurological cases there, including patients who had received spinal injuries resulting in limb differentiation. His paper on these is still well cited by researchers in motor behaviour, and he is credited with formulating the concept of the motor programme. At this time he also acquired the necessary techniques for performing ablation studies with rats, which allowed him to look for the neural basis of the connectionism of behaviouristic theory. He attempted to find localized sites in the brain specific to various visual discriminations involved in maze learning and these results suggested field theory. It has been said that the discriminations required in his tasks involved cues in modalities other than vision, which would lead to cautious acceptance of this conclusion.

    He proposed two influential principles. The first, mass action, is the mediation of certain learning tasks by the cortex as a whole. Greater localization than he suggested has subsequently been found, but mass action events have been found within localized areas. The second is equipotentiality or the ability of certain parts of a sensory system to assume the functions of the other parts. This has subsequently been supported.

    Lashley also made a major contribution to neuroanatomy by tracing the connections from the retina to the lateral geniculate nucleus and then to the cortex, and by demonstrating the point-to-point projections later confirmed with more sophisticated techniques.

    Ann Colley

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