Leslie, J.C. (2006).
Herbert Spencer’s contributions to behavior analysis: A retrospective review of Principles of Psychology.
Journal of the Experimental Analysis of Behavior, 86, 123-129.
Herbert Spencer’s Principles of Psychology (1855, first edition) was regarded by his
contemporaries, including William James and John Dewey, as a major contribution to what was
then a very new discipline. In this book he first expounded his ideas about both evolution
of species and how behavior of the individual organism adapts through interaction with the
environment. His formulation of the principle that behavior changes in adaptation to the
environment is closely related to the version of the law of effect propounded some years
later by Thorndike. He can thus be seen as the first proponent of selectionism, a key tenet
of behavior analysis. He also explicitly attacked the then prevailing view of free will as
being incompatible with the biologically grounded view of psychological processes that he was
advocating, and thus put forward ideas that were precursors of B. F. Skinner’s in
this important area of debate.
Key words: Spencer, selectionism, adaptation