Up or Down: The Influence of Upcoming Reinforcement on Consummatory and Operant Behavior

Abstract

Research has shown that animal subjects that are given a chance to consume a low-valued substance will consume less of it if a high-valued substance will soon be available than they would if the low-valued substance were to remain available (negative consummatory contrast). Research has also shown that subjects that lever press for a low-valued reinforcer will press the lever more often for that reinforcer if they will soon be able to lever press for a high-valued reinforcer than they would if they continue to press for the low-valued reinforcer (positive induction). The present study investigated these different changes in behavior across 3 experiments. The results suggest that the occurrence of contrast or induction does not depend on the type of substances that are used. We argue that further investigation of the contrast vs. induction issue is warranted because it has empirical, theoretical, and applied implications.

Relative reward effects on operant behavior: Incentive contrast, induction and variety effects

“…This ‘Crespi Effect’ relied on a between group comparison with controls not experiencing an alteration of outcome value. Recent work on incentive contrast has found the effect to be more complicated than originally proposed (Binkley et al, 2014; Nyland et al, 2012; Ortega et al, 2011; King et al, 2002). Based on the complex but crucial nature of relative reward processing, it is vital that new paradigms are developed and explored to clarify interactions and overcome obstacles in understanding factors involved in incentive contrast as well as similar effects on behavior (Webber et al, 2011; Cromwell, 2010; Cromwell et al, 2005; Watanabe et al, 2001).…”

“…Another complicating issue is the existence of different forms of ‘contrast’ that can involve generalization among outcomes and relative effects that are opposite to traditional contrast effects (Weatherly et al, 2001; King et al, 2002; Lupfer-Johnson et al, 2010). For example, positive induction has been proposed as an opponent effect to anticipatory negative contrast (Weatherly et al, 2004).…”

Induction when rats lick for 1% liquid-sucrose reinforcement

“…The rats that pressed levers, however, collected and consumed the sucrose in the different halves of the session from the same trough, and induction was observed. Similar outcomes occurred in King et al (2002). In fact, in all of the studies from our laboratory that have reported positive induction, the lesser valued reinforcer in the first half of the session has been delivered to the same place as the upcoming, more valued substance.…”

“…For instance, Flaherty and Rowan (1985) showed that rats given 3-min free access to a 0.15% saccharin solution consumed less of it if the upcoming 3-min period would allow access to a 32% sucrose solution rather than continued access to 0.15% saccharin. King, Brandt, and Weatherly (2002) demonstrated that the same subjects would display consummatory contrast and induction when responding for the same substances. In the first phase of their Experiment 3, rats were given 3-min periods of free access to 1% liquid sucrose, followed after a 15-s delay by 3-min periods of free access to 1% sucrose, 32% sucrose, or 45-mg food pellets, in different conditions.…”

“…However, it should be possible to measure both behaviours in the same procedure. In fact, given that King et al (2002) demonstrated that positive induction and consummatory contrast could be observed in the same subjects, it would seem reasonable to predict that upcoming 32% sucrose would produce an increase in lever pressing (induction) and a decrease in licking during reward consumption (contrast). Experiment 3 tested this idea by having rats press a lever for 1% sucrose rewards in the first half of the session and, in different conditions, either 1% or 32% sucrose rewards in the second half.…”