Watson's behaviorism: a comparison of the two editions (1925 and 1930).

J.B. Watson's Behaviorism, a complete presentation of the mature psychological points of view of its author, had 2 editions, in 1925 and 1930, which presented significant differences in their texts. Although Watson maximized such variations, to the point of considering the 2nd edition as nearly a brand-new book, both suppressions and additions reveal his feelings when presenting his ideas to a general audience. Such variations are here presented through an in-depth analysis.