The Monty Hall dilemma with pigeons: No, you choose for me.

In the Monty Hall dilemma, humans are initially given a choice among three alternatives, one of which has a hidden prize. After they have chosen, but before revealing whether they have won the prize, subjects are shown that one of the remaining alternatives does not have the prize, and they are asked whether they want to stay with their original choice or switch to the remaining alternative. Switching results in obtaining the prize two thirds of the time, but even after considerable training, humans fail to consistently adopt the optimal strategy of switching. Pigeons, however, show closer-to-optimal switching performance with this task. One of the reasons that humans choose suboptimally is their mistaken assumption that with two alternatives, the probabilities of winning the prize are the same for staying and switching, and staying may be preferred because of a sense of endowment (ownership of the initial response). When we tried to produce an endowment effect in pigeons by requiring 20 pecks (rather than one peck) for the initial choice, it actually resulted in faster acquisition of the switching response. In the present research with pigeons, we examined the finding from human research that subjects are more likely to switch if they are not responsible for making the initial choice (another approach to the endowment effect). Inconsistent with the findings with humans, we found that when the initial choice was made for the pigeons, they actually showed less of a tendency to switch than did pigeons that made the initial choice themselves.