African mouthbreeders learned to strike at a target for food reward at the rate of 1 trial per day; latencies of 4 groups were measured during acquisition and extinction. In a 2 X 2 design, 2 other variables were introduced: (a) in acquisition, constant reinforcement vs. partial reinforcement; and (b) throughout the experiment, high drive vs. low drive. "Resistance to extinction increased with drive, and at both drive levels partial reinforcement produced less resistance to extinction than did consistent reinforcement." (PsycINFO Database Record (c) 2006 APA, all rights reserved)