Adjustment to reward reduction (but no negative contrast) in rats 11, 14, and 16 days of age.

Abstract

Successive negative con-rast (SNC) was investigated in 3 experiments involving infant rats in the 11-16 day old age range. Reward consisted of the opportunity to suckle an anesthetized dam, either with milk delivery (high reward) or no milk delivery (low reward). Despite a clear effect of reward magnitude in the preshift phase, in none of the experiments was SNC found. This absence of SNC did not depend on drive level or the inability of these young animals to discriminate the aftereffects of the 2 reward conditions. The ontogeny of appetitive behavior, inhibition and theories of instrumental learning were discussed.