Near Misses in Slot Machine Gambling Developed Through Generalization of Total Wins

The purpose of the present study was to evaluate the development of the near miss effect in slot machine gambling as a product of stimulus generalization from total wins. The study was conducted across two experiments. Twelve college students participated in the first experiment, which demonstrated that greater post-reinforcement pauses followed losing outcomes that were formally similar to total wins, relative to losing outcomes that were formally dissimilar [F (5, 7) = 5.24, p = .025] along a generalization gradient (R (2) = .96). Additionally, 11 out of 12 participants showed greater response latencies following near-misses than following total wins. Thirteen college students participated in the second experiment, which demonstrated that symbols that more saliently indicated a loss resulted in lower response latencies than functionally equivalent but visually dissimilar losing symbols [F (3, 10) = 15.50, p = .01]. A generalization gradient was observed across winning symbols (R (2) = .98), and an inverse of the gradient observed across winning symbols was observed across symbols that were the least formally similar (R (2) = .69). The present study replicates and extends previous research on near misses in slot machine gambling, and provides discussion around the clinical utility of such findings on the prevention of problem gambling.