Probabilistic Reward Learning Capacity Among Individuals Experiencing Problem Gambling

Abstract

Background: Deficits in reward learning capacity have been well documented among substance use disorders. However, few studies directly examine whether alterations in forming novel associations may be present in individuals with problem gambling (PG). Purpose: The current study investigated the capacity for individuals experiencing PG behaviour to form novel, non-gambling reward associations using a well-established behavioural paradigm of reinforcement learning known as the Probabilistic Reward Task (PRT). Methods: 20 participants with PG and 20 age-matched control comparisons (CC) completed the PRT, which assessed the development of a response bias (RB) – the preferential response to stimuli (‘rich’ stimulus) associated with more frequently presented reward contingencies. Results: PG and control participants did not develop a RB for the more frequently rewarded stimuli. Across trials, both groups demonstrated improvements in discriminability and accuracy, in addition to a trending reduction in response time (RT). Both groups displayed greater accuracy and shorter RTs when identifying the rich stimulus, relative to the lean stimulus (less frequently rewarded stimuli) across all blocks. Greater gambling severity within the PG group, but not CC group, was positively correlated with a heightened RB. Conclusion: Although individuals with PG nor their control comparisons exhibited RB formation to novel, non-gambling reward stimuli, the enhanced discriminability, rich accuracy, and reduced RT across blocks indicate some degree of task learning occurred and that participants were able to consistently and more efficiently identify the rich stimuli, relative to lean stimuli. Individuals with PG exhibiting more severe gambling behaviours displayed a heightened RB, indicating these individuals may be especially sensitive to forming novel reward associations. Further elucidating these behaviours could inform targeted interventions and public health strategies pertaining to the prevention and treatment of maladaptive gambling patterns.