Page 41 - History of Psychology

Chapter

Psychobiology 12

Psychobiology attempts to explain psychological phenomena in terms of their
biological foundations. The search for the biological foundations of behavior has
been a recurring theme in the history of psychology and has been represented by
such individuals as Hippocrates, Aristotle, Galen, Hartley, Bain, Weber, Fechner,
Helmholtz, Pavlov, and Freud. Psychobiological research begins with the
pioneering work of Karl Lashley as well as some of the illustrious psychobiologists
he influenced.

Karl Spencer Lashley (1890–1958) was born in Davis, West Virginia, an only child.
Lashley received his undergraduate education at West Virginia University and his
Masters in bacteriology at the University of Pittsburgh. From there, he went to
Johns Hopkins University, where he received his PhD in genetics in 1914.
Nevertheless, while at Johns Hopkins, Lashley came under the influence of John
Watson, and much of Lashley’s early work reflected Watson’s ideas. Lashley’s
formal collaboration with Watson eventually ended because Lashley was
interested in seeking the neurophysiological bases of conditioned reflexes and
Watson was not. Although the two went their separate ways professionally, they
remained friends.

Lashley made two major observations, One was that loss of ability following
destruction of parts of the cortex is related more to the amount of destruction
than to the location of destruction. This finding, called mass action, indicated that

the cortex works as a unified whole, as the Gestaltists had maintained. The second
observation was that any part of a functional area of the brain can perform the
function associated with that area. For example, within the visual area of the
cortex, any of the cells within that area allow vision to occur. To destroy a brain
function, then, the entire brain area associated with that function would need to
be destroyed. If any part of the area were spared, the function would still be
maintained. Lashley called this second observation equipotentiality, and it too
supported the contention that the brain acted as an integrated whole and not as a
mechanistic switchboard.

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