An experimental test of the prediction that the gradient of stimulus generalization of an avoidance habit motivated by the learned drive of fear should be steeper than that of one motivated by the primary drive of mild pain induced by electric shock. 60 albino rats were trained, and tested in the same and a different alley. The measure was force of pull against a restraint. The prediction was verified. (PsycINFO Database Record (c) 2006 APA, all rights reserved)