Susceptibility to the gambling near-win effect in optimists versus pessimists: An event-related potential study

Near-win outcomes have a motivational effect on gambling behavior and are associated with gambling addiction. Information about the personality traits that determine susceptibility to the near-win effect is scare. Here, we assessed the event-related potentials (ERPs) and behavioral responses of 27 optimists and 25 pessimists following gambling outcomes in a modified slot-machine gambling task to examine whether optimists are more susceptible than pessimists to the near-win effect. The result showed that the mean amplitudes of analyzed ERPs elicited by near-win outcomes did not differ between the optimist and pessimist groups, but the groups exhibited different behavioral patterns in the task. The optimists tended to make risky bets following near-wins, whereas pessimists tend to be cautious. In addition, we observed a negative trend in the correlation between the probability of risky betting and the P300 amplitude difference between near-win and full-miss outcome trials in the pessimism group, but not in the optimism group. The present study revealed some potentially interesting differences in near win processing between the optimists and pessimists that may provide a foundation for future examination of individuals who are trait susceptible to the near-win effect and gambling addiction.