Consistent with human gambling behavior but contrary to optimal foraging theory, pigeons show a strong preference for an alternative with low probability and high payoff (a gambling-like alternative) over an alternative with a greater net payoff (Zentall & Stagner, Proceedings of the Royal Society B, 278, 1203Society B, 278, -1208Society B, 278, , 2011. In the present research, we asked whether humans would show suboptimal choice on a task involving choices with probabilities similar to those for pigeons. In Experiment 1, when we selected participants on the basis of their self-reported gambling activities, we found a significantly greater choice of the alternative involving low probability and high payoff (gambling-like alternative) than for a group that reported an absence of gambling activity. In Experiment 2, we found that when the inhibiting abilities of typical humans were impaired by a self-regulatory depletion manipulation, they were more likely to choose the gambling-like alternative. Taken together, the results suggest that this task is suitable for the comparative study of suboptimal decision-making behavior and the mechanisms that underlie it.Keywords decision making . suboptimal choice . gambling . humans . pigeons A subset of suboptimal decision making can be characterized as making a decision to choose a low-probability but high-payoff alternative (e.g., playing slot machines or buying lottery tickets) over a high-probability, low-payoff alternative (not gambling), such that the net expected return is less than what one has wagered. In this kind of gambling, over the long term, one is very likely to lose more than one wins, and having sufficient experience with the game to learn about the odds of winning does not appear to reduce its frequency. It appears that gamblers tend to over-attend to wins and discount losses (the availability heuristic; Tversky & Kahneman, 1974).Recently, Zentall and colleagues studied suboptimal decision-making processes in pigeons (Gipson, Alessandri, Miller, & Zentall, 2009;Stagner & Zentall, 2010;Zentall & Stagner, 2011). They asked whether pigeons would show choice behavior analogous to the suboptimal behavior shown by humans when humans purchase a lottery ticket or engage in casino gambling. To answer this question, Zentall and Stagner designed a task that may be considered analogous to human gambling (see Fig. 1a). In this task, pigeons are given a choice between one alternative reliably associated with three reinforcers (analogous to money in one's pocket) and a second alternative (analogous to gambling) associated with a low-probability, high-payoff stimulus on some trials (10 pellets on 20% of the trials) or a highprobability, zero-payoff stimulus on others. In one sense, the task is analogous to suboptimal human gambling, because the average payoff for the first alternative (with an overall mean reinforcement per trial of 3 pellets) is greater than that of the second alternative (with an overall mean reinforcement per trial of 2 pellets). Results show...