In no case did doing so lead to a negative contrast effect in responding for 1% sucrose in the first component.
But it did not produce a systematic negative contrast effect. Positive induction (observed for 2 subjects) was still observed twice as often as negative contrast (observed for 1 subject).
In short, although it remains possible that food-pellet reinforcement may potentially produce a negative contrast effect in responding for 1% sucrose, the present study found little evidence to indicate under what conditions this outcome would be observed.
Such decrements in responding have been termed negative contrast effects (NCE).
Although negative contrast effects in consummatory behavior are typically demonstrated using food-deprived subjects (Flaherty, 1982; Flaherty, Becker, & Checke, 1983; Flaherty & Largen, 1975.), NCE has also been obtained with nondeprived subjects (Brazier & Dachowski, 1991; Flaherty & Largen, 1975; Riley & Dunlap, 1979).
Subjects in a currently nondeprived state should respond to the hedonic value of the solutions and display enduring and recurring positive and negative contrast effects characteristic of nondeprived subjects, regardless of their initial deprivation condition.
Although the mean weight of initially deprived subjects remained significantly below that of initially nondeprived subjects throughout Phase 2, the pattern of negative contrast effects was characteristic of the current deprivation condition.
Within-subjects positive and negative contrast effects in rats.