ABSTRACT
It is proposed that the dominance of continuity learning theory as set against noncontinuity learning theory during the middle third of the 20th century rested importantly on its derivation from Darwin's theory of evolution. The kinship is shown in several ways. First, Thorndike and Hull echoed the principle of natural selection in their belief that behaviors underwent gradual modification because acts that were attended steadily by favorable consequences tended to occur with increasing frequency. Second, they denied both nonphysical explanations of behavior and a priori purposes which might guide that behavior. Third, the laws of learning were said to hold for all organisms. It is argued that the continuity approach may have enjoyed success because it was consistent with the Darwinian world view. Had punctualist, rather than gradualist, explanations of evolution come to the fore in the late 19th century, learning theories might have proceeded quite differently with the dominance of non-continuity approaches.