Choice responses during consummatory successive negative contrast in rats

Abstract

In rats, a change from a preferred solution (e.g. 32% sucrose) to a less preferred (e.g. 4%) produces an abrupt decrement in consumption below the levels of an unshifted group that always had access to the less preferred solution. This phenomenon -known as consummatory successive negative contrast effect- occurs with simultaneous changes in ambient or gustative cues and with multiple response options, with the reinforcer located in several different places. In the present experiment a group of rats was trained during the pre-shift phase with an almond flavored preferred solution (i.e. 32%A) and another group with a less preferred flavored solution (i.e. 4%A). Post-shift phase took place in a newly different context where all animals could choose between 4% and 4%A. Results showed a negative contrast effect in the downshifted animals and a preference for the familiar flavored solution in both groups.