Contrafreeloading in Rats Is Adaptive and Flexible: Support for an Animal Model of Compulsive Checking

Abstract

Contrafreeloading involves working unnecessarily to obtain a reward that is otherwise freely available. It has been observed in numerous species and can be adaptive when it provides an organism with updated information about available resources. Humans frequently update their knowledge of the environment through checking behaviors. Compulsive checking occurs when such actions are performed with excessive frequency. In a putative animal model of compulsive checking, rats treated chronically with the dopamine agonist quinpirole display exaggerated contrafreeloading for water. Although this effect has been attributed to behavioral rigidity, some evidence suggests the behavior remains somewhat flexible and may be adaptive under certain conditions. We assessed the ability of quinpirole-treated rats with contrafreeloading experience to adapt to changing contingencies by requiring them to alternate between response levers. Rats treated with quinpirole or saline were first trained to obtain water by pressing either of two levers. Next, free water was made available for 8 days, and contrafreeloading was measured. Rates of contrafreeloading were significantly higher in the drug-treated rats than in controls. On the following 5 days, each reward caused the associated lever to become inactive until a reward was earned from the alternate lever. Quinpirole-treated rats learned this new response requirement more quickly than controls. Thus, exaggerated checking behavior induced by chronic quinpirole treatment can be advantageous when environmental contingencies change. These results provide support for this animal model of compulsive checking and hint at the presence of a specialized neural checking module involving the dopamine system.

Mesolimbic dopamine projections mediate cue-motivated reward seeking but not reward retrieval in rats

“…For instance, environmental cues that signal reward availability increase attempts to seek out (Estes, 1948; Corbit and Balleine, 2016) and retrieve reward (Marshall and Ostlund, 2018). While the ability to develop and modify action sequences is normally adaptive, this process may become dysregulated in certain conditions, such as obsessive-compulsive disorder (Joel and Avisar, 2001; Korff and Harvey, 2006; Frederick and Cocuzzo, 2017) and drug addiction (Tiffany, 1990; Graybiel, 2008; Volkow et al, 2013), leading to maladaptive behaviors. Despite this, the behavioral and neural mechanisms responsible for regulating reward seeking and retrieval are not well understood.…”

Initial evidence for eliciting contrafreeloading in grey parrots (Psittacus erithacus) via the opportunity for playful foraging.

“…Such findings correlate with studies suggesting that information is most valuable when variance is greatest (Bell, 1991). Interestingly, contrafreeloading in rats is affected by administering drugs that influence the dopamine system to favor information-gathering (Frederick & Cocuzzo, 2017), also suggesting the rewarding nature of such behavior. Again, these data do not entirely explain the existence of contrafreeloading in other contexts.…”