When humans engage in organized gambling, they are generally choosing sub-optimally. That is, losses are almost always greater than gains. We have developed a model of sub-optimal gambling in which animals prefer an occasional signalled high payoff (10 pellets 20% of the time; 2 pellets on average) rather then a reliable alternative with a signal for a lower payoff (3 pellets 100% of the time). This effect appears to result from the strong conditioned reinforcement associated with the stimulus that is followed by a high payoff. Surprisingly, although it is experienced four times as much, the stimulus that is never followed by reinforcement does not appear to result in significant conditioned inhibition. Similarly, human gamblers tend to overvalue wins and undervalue losses. We have also found that pigeons gamble less when food is less restricted (rich people gamble less than poor people) and they also gamble less when they have been exposed to an enriched environment rather than being kept in an individual cage (for humans, gambling is said to be a form of entertainment). This animal model may provide a useful analog to human gambling behavior, one that is free from the influence of human culture, language, social reinforcement, and other experiential biases.
Review Thomas R. Zentall’s biographical statement.