Choice behavior of pigeons (Columba livia), college students, and preschool children (Homo sapiens) in the Monty Hall dilemma

Abstract

In the Monty Hall dilemma, an individual chooses between three options, only one of which will deliver a prize. After the initial choice, one of the nonchosen options is revealed as a losing option, and the individual can choose to stay with the original choice or switch to the other remaining option. Previous studies have found that most adults stay with their initial choice, although the chances of winning are 2/3 for switching and 1/3 for staying. Pigeons, college students, and preschool children were given many trials on this task to examine how their choices might change with experience. The college students began to switch on a majority of trials much sooner than the pigeons, contrary to the findings by Herbranson and Schroeder (2010) that pigeons perform better than people on this task. In all three groups, some individuals approximated the optimal strategy of switching on every trial, but most did not. Many of the preschoolers immediately showed a pattern of always switching or always staying and continued this pattern throughout the experiment. In a condition where the probability of winning was 90% after a switch, all college students and all but one pigeon learned to switch on nearly every trial. The results suggest that one main impediment to learning the optimal strategy in the Monty Hall task, even after repeated trials, is the difficulty in discriminating the different reinforcement probabilities for switching versus staying.

Figure 1

Mean switching percentages for the pigeons in each session of Experiment 1. The error bars are standard errors of the mean.

Figure 2

Switching percentages are shown for each pigeon in Experiment 1 in 5-session blocks. For each condition, the left panel shows the results from the 6 pigeons that had the highest switching percentages at the end of the 67% Condition; the right panel shows the results from the other 6 pigeons.

Figure 3

Mean switching percentages are shown for the college students in each of the three conditions of Experiment 2, plotted in blocks of 25 trials.

Figure 4

Switching percentages are shown for each college student in Experiment 2 in 25-trial blocks. For each condition, the left panel shows the results from the 6 students who had the highest switching percentages, and the right panel shows the results from the other 6 students. The keys identify individual participants in the form “condition-participant” (e.g., “80-3” refers to the third participant in the 80% condition).

Figure 5

Mean switching percentages are shown for the preschool children in Experiment 3, plotted in blocks of 10 trials. The error bars are standard errors of the mean.

Figure 6

Mean switching percentages are shown for each child in Experiment 3, plotted in blocks of 10 trials. The results for the 7 children with the highest switching percentages are in the left panel, for those with intermediate switching percentages in the center panel, and for those with the lowest switching percentages in the right panel.