Consummatory successive negative contrast in mice

Mice exposed to a 32% sugar solution during 10 daily sessions later rejected a 4% solution significantly more than control mice always given access to the 4% solution. With 3-h access to the solutions, Group 32-4 consumed significantly less than Group 4-4 during the first postshift session; however, an increase in the consumption level in Group 4-4 from the last preshift to the postshift sessions may have inflated the size of the effect. The phenomenon was clearly demonstrated when mice received 1-h access to the solutions (Experiments 2 and 3). This effect was eliminated by he administration of diazepam (4 mg/kg) during the postshift period (Experiment 3). This is the first demonstration of successive negative contrast in a consummatory response situation with mice. The species generality of successive negative contract in consummatory and instrumental response systems is discussed. (C) Academic Press.