10 pairs of matched Shetland sheepdog puppies were run in a right turn alleyway, 1 trial per day for 30 days, under 2 levels of reinforcer deprivation. The reinforcer was 2 min. of contact with a passive person, and deprivation levels were determined by the duration of exposure to the person just prior to an alleyway trial. Response speed of puppies under the high deprivation condition (relatively short prior exposure to the reinforcer) was significantly greater than that of puppies under the low deprivation condition (relatively long prior exposure to the reinforcer). When deprivation conditions of this reinforcer are varied the asymptotes of puppies' instrumental response speed curves are affected analogously to those of rats under food or water deprivation. (PsycINFO Database Record (c) 2006 APA, all rights reserved)