Encyclopedia, Difference between revisions of "Karl Lashley" - New World

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'''Karl Spencer Lashley''' (born June 7, 1890 – died August 7, 1958) was an American [[psychologist]] and [[behaviorist]], well-remembered for his influential contributions to the study of [[learning]] and [[memory]]. Based on his research on [[biology|biological]] locus of memory (or "[[Engram (neuropsychology)|engram]])", he was one of the first to claim that memories were not localized to one part of the [[brain]], but were widely distributed throughout the [[Cerebral cortex|cortex]].
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'''Karl Spencer Lashley''' (June 7, 1890 – August 7, 1958) was an American [[psychologist]] and [[behaviorism|behaviorist]], well-remembered for his influential contributions to the study of [[learning]] and [[memory]]. Based on his research on [[biology|biological]] locus of memory (or "engram"), he was one of the first to claim that memories were not localized to one part of the [[brain]], but were widely distributed throughout the [[Cerebral cortex|cortex]].
  
 
==Life==
 
==Life==
  
Karl Lashley was born in Davis, West Virginia. As a child he showed great interest for animals, and his mother, Maggie Lashley, encouraged his intellectual pursuits. He entered the [[University of West Virginia]] at the age of fifteen, and signed for the zoology class under famous neurologist John Black Johnston. That was the time when Lashley decided to pursue career in zoology. Lashley graduated in 1910 and obtained teaching fellowship at the [[University of Pittsburgh]], where he received his Masters Degree in bacteriology. He then went on to study genetics at [[Johns Hopkins University]], under zoologist Herbert S. Jennings. At the same time, Lashley became associated with the psychiatrist [[Adolf Meyer]], and psychologist [[John B. Watson]], the association that significantly influenced Lashley’s life and made him turn toward studies of animal behavior. During three years of [[postdoctoral]] work on [[vertebrate]] behavior (1914-17), he began formulating the research program that was to occupy the remainder of his life.  
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'''Karl Spencer Lashley''' was born on June 7, 1890 in Davis, West Virginia. As a child he showed great interest in animals, and his mother, Maggie Lashley, encouraged his intellectual pursuits.
  
In 1920 he became an assistant professor of psychology at the [[University of Minnesota]], [[Minneapolis]], where his prolific research on brain function gained him a professorship in 1924. Next several years Lashley collaborated with Shepherd Franz, at St. Elizabeth's Hospital in Washington, DC, examining effects of lesions of the frontal cortex on learning abilities in rats. This work was the foundation for Lashley’s major work, ''Brain Mechanisms and Intelligence'' (1929).
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He entered the University of West Virginia at the age of fifteen, and signed up for the [[zoology]] class under famous neurologist John Black Johnston. That was the time when Lashley decided to pursue a career in zoology.  
  
Lashley was appointed a professor at the [[University of Chicago]] in 1929, where he taught until 1935. In 1929 he served as president of the ''[[American Psychological Association]]''. He moved to [[Harvard University]] in 1935, and stayed there until his retirement in 1955. He also served as director of the Yerkes Laboratories of Primate Biology in Orange Park, Florida, from 1942 to 1955.  
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Lashley graduated in 1910 and obtained a teaching fellowship at the University of Pittsburgh, where he received his Masters Degree in [[bacteriology]]. He then went on to study [[genetics]] at [[Johns Hopkins University]], under zoologist Herbert S. Jennings. At the same time, Lashley became associated with the [[psychiatry|psychiatrist]] [[Adolf Meyer]], and psychologist [[John B. Watson]], the association that significantly influenced Lashley’s life and made him turn toward studies of [[animal behavior]]. During three years of postdoctoral work on [[vertebrate]] behavior (1914-17), he began formulating the research program that was to occupy the remainder of his life.  
  
Lashley married Edith Ann Baker in 1918. After Edith died in 1948 Lashley remarried in 1957 to Claire Imredy Schiller, widow of the Hungarian psychologist Paul Harkai Schiller. Lashley died on August 7, 1958, in Poitiers, France.
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In 1920, he became an assistant professor of [[psychology]] at the [[University of Minnesota]] in Minneapolis, where his prolific research on [[brain]] function gained him a professorship in 1924. Next several years Lashley collaborated with Shepherd Franz, at St. Elizabeth's Hospital in Washington, DC, examining effects of lesions of the frontal [[cortex]] on [[learning]] abilities in [[rat]]s. This work was the foundation for Lashley’s major work, ''Brain Mechanisms and Intelligence'' (1929).
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Lashley was appointed professor at the [[University of Chicago]] in 1929, where he taught until 1935. In 1929, he served as president of the American Psychological Association. He moved to [[Harvard University]] in 1935, and stayed there until his retirement in 1955. He also served as director of the Yerkes Laboratories of Primate Biology in Orange Park, Florida, from 1942 to 1955.
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Lashley married Edith Ann Baker in 1918. After Edith died in 1948, Lashley remarried in 1957 to Claire Imredy Schiller, widow of the [[Hungary|Hungarian]] [[psychologist]] Paul Harkai Schiller. Lashley died on August 7, 1958, in Poitiers, [[France]].
  
 
==Work==
 
==Work==

Revision as of 23:18, 20 August 2006


Karl Spencer Lashley (June 7, 1890 – August 7, 1958) was an American psychologist and behaviorist, well-remembered for his influential contributions to the study of learning and memory. Based on his research on biological locus of memory (or "engram"), he was one of the first to claim that memories were not localized to one part of the brain, but were widely distributed throughout the cortex.

Life

Karl Spencer Lashley was born on June 7, 1890 in Davis, West Virginia. As a child he showed great interest in animals, and his mother, Maggie Lashley, encouraged his intellectual pursuits.

He entered the University of West Virginia at the age of fifteen, and signed up for the zoology class under famous neurologist John Black Johnston. That was the time when Lashley decided to pursue a career in zoology.

Lashley graduated in 1910 and obtained a teaching fellowship at the University of Pittsburgh, where he received his Masters Degree in bacteriology. He then went on to study genetics at Johns Hopkins University, under zoologist Herbert S. Jennings. At the same time, Lashley became associated with the psychiatrist Adolf Meyer, and psychologist John B. Watson, the association that significantly influenced Lashley’s life and made him turn toward studies of animal behavior. During three years of postdoctoral work on vertebrate behavior (1914-17), he began formulating the research program that was to occupy the remainder of his life.

In 1920, he became an assistant professor of psychology at the University of Minnesota in Minneapolis, where his prolific research on brain function gained him a professorship in 1924. Next several years Lashley collaborated with Shepherd Franz, at St. Elizabeth's Hospital in Washington, DC, examining effects of lesions of the frontal cortex on learning abilities in rats. This work was the foundation for Lashley’s major work, Brain Mechanisms and Intelligence (1929).

Lashley was appointed professor at the University of Chicago in 1929, where he taught until 1935. In 1929, he served as president of the American Psychological Association. He moved to Harvard University in 1935, and stayed there until his retirement in 1955. He also served as director of the Yerkes Laboratories of Primate Biology in Orange Park, Florida, from 1942 to 1955.

Lashley married Edith Ann Baker in 1918. After Edith died in 1948, Lashley remarried in 1957 to Claire Imredy Schiller, widow of the Hungarian psychologist Paul Harkai Schiller. Lashley died on August 7, 1958, in Poitiers, France.

Work

Lashley was at the same time an experimental researcher and a theoretician. His early works included study of sexual behavior of hydras and study of seabirds. In both of those areas he followed the behavioristic theory of J.B. Watson, to whose approach he remained loyal for the rest of his career.

Lashley’s later work included research on brain mechanisms related to sense receptors and on the cortical basis of motor activities. He studied many animals, including primates, but his major work was done on the measurement of behavior before and after specific, carefully quantified, induced brain damage in rats. He trained rats to perform specific tasks, then lesioned specific areas of the rat cortex, either before or after the animals received the training. The cortical lesions had specific effects on acquisition and retention of knowledge. This work led Lashley to an another area of study, the one that he focused the rest of his career on, and the one he remained the most famous after - cerebral localization

The study of cerebral localization was an area in psychology where lot of controversies was generated in the first half of 20th century. Psychologists like Gall, Broca, Fritsch and Hitzig, Ferrier, and Munk believed that particular local areas in the brain were responsible for particular brain functions, therefore advocating for the exact cerebral localization. On the other side, researchers like Flourens, Goltz, and Franz held that brain functions are dispersed around the brain, and that different areas control particular function. Combining the insights from behaviorism and his research with trained rats, Lashley hypothesized the existence of a local area in the brain where memories of learned responses are stored. Lashley called such area engram (memory trace). The idea that learned responses are localized in the brain was in line with behavioristic approach, and Lashley devoted his career to find such area. He used mazes of various difficulty and size where he trained rats to find the exit. After rats memorized where the exit was, Lashley would perform different lesions on rats’ brains, with assumption to remove memory traces that brains created. However, after years of research, Lashley failed to find engrams. In 1929 Lashley published his masterpiece Brain Mechanisms and Intelligence: A Quantitative Study of Injuries to the Brain, where he summarizes years of his research on cerebral localization. In it he renounced the existence of a precise local area in the brain that is responsible to hold memories. The study had a profound impact on the young field of physiological psychology and on the future research on brain.

By 1950, Lashley had distilled his research into two theories. The principle of "mass action" stated that the cerebral cortex acts as one—as a whole—in many types of learning. The different areas of brain participate in learning, and the memory traces are dispersed over entire cortex. The principle of "equipotentiality" stated that if certain parts of the brain are damaged, other parts of the brain may take on the role of the damaged portion. Locus is thus not important. As Lashley (1950) puts it himself:

This series of experiments has yielded a good bit of information about what and where the memory trace is not. It has discovered nothing directly of the real nature of the memory trace. I sometimes feel, in reviewing the evidence of the localization of the memory trace, that the necessary conclusion is that learning is just not possible. It is difficult to conceive of a mechanism that can satisfy the conditions set for it. Nevertheless, in spite of such evidence against it, learning sometimes does occur.

Legacy

Based on his work with animals and the application of that knowledge to universal principles of behavior, Lashley can be seen as a pioneer of ethology and comparative psychology.

One of the fields in psychology that owns the most to Karl Lashley is the field of physiological psychology. Lashley’s work on localization of learning and memory shaped the future research in brain studies. It showed that brain was the more complex that it was thought, and that more studies need to be done in this field in order for any definite conclusion to be made. The research on engrams continued after Lashley’s death, with the work on Donald O. Hebb, a student of Lashley. Lashley’s insights were in line with modern theories used by connectionists – theories of artificial intelligence, cognitive science, neuroscience, psychology and philosophy of mind.


Publications

  • Lashley, Karl S. 1923. The behavioristic interpretation of consciousness. Psychological Bulletin, 30, 237-272 & 329-353
  • Lashley, Karl S. 1929. Brain mechanisms and intelligence. Chicago: Chicago University Press
  • Lashley, Karl S. 1930. Basic neural mechanisms in behavior. Psychological Review, 37, 1-24
  • Lashley, Karl S. (ed.). 1932. Studies In The Dynamics Of Behavior. The University of Chicago Press
  • Lashley, Karl S. 1935. The mechanism of vision, Part 12: Nervous structures concerned in the acquisition and retention of habits based on reactions to light. Comparative Psychology Monographs, 11, 43-79.
  • Lashley, Karl S. 1950. In search of the engram. Society of Experimental Biology Symposium, 4, 454-482.

References
ISBN links support NWE through referral fees

  • Orbach, Jack (ed.). 1981. Neuropsychology After Lashley: Fifty Years Since the Publication of Brain Mechanisms and Intelligence. Lawrence Erlbaum Associates. ISBN 0898590884
  • Sheehy, Noel (ed.). 2002. Biographical Dictionary of Psychology. London: Routledge. ISBN 0415285615.

External links

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