Impaired learning from food rewards and game punishments in internet gaming disorder: Behavioral and ERP evidence from a probabilistic reward task.

Individuals with Internet Gaming Disorder (IGD) exhibit heightened engagement with gaming alongside diminished responsiveness to natural rewards such as food. Whether this dissociation extends to reward learning, a core process linking outcomes to future behavior, remains unclear. Using a Probabilistic Reward Task combined with event-related potentials, we examined reinforcement and extinction learning across food and gaming rewards in individuals with IGD (n = 50) and recreational game users (RGUs; n = 50). In the reinforcement learning task, the IGD group showed significantly smaller response biases and attenuated Reward Positivity (RewP) amplitudes compared to RGUs when processing food rewards, whereas no significant group differences emerged for gaming rewards. In the extinction learning task, the IGD group exhibited smaller response biases and reduced RewP amplitudes across both reward types compared to RGUs, with the most pronounced impairment for gaming punishments. Additionally, the IGD group displayed larger Late Positive Potential (LPP) amplitudes for gaming reward versus neutral feedback, a pattern not observed for food rewards. Across both experiments, RewP amplitude was positively correlated with response bias and negatively correlated with IGD symptom severity. These findings provide converging behavioral and neurophysiological evidence for domain-specific deficits in reward learning in IGD, characterized by impaired reinforcement from natural rewards and deficient extinction from gaming punishments. Selective dysfunction in reward learning may represent one neurocognitive pathway through which gaming behaviors are strengthened and maintained at the expense of natural reward processing in IGD.