stimulus, is present; but which ceases, being replaced by a state of relative rest, when that stimulus has ceased to act on the sense-organs." One of the students of Lorenz, Monika Holzapfel, extended these notions to suggest that states of rest are goals of behavior (Holzapfel, 1940).Within his framework of appetites and aversions, Craig in his essay of 1921 described aggression as an aversion, in contrast to Lorenz, who regarded it as an appetite (Lorenz, 1966).

From 1937, Craig worked as a temporary ornithologist at the New York State Museum,