PROCRASTINATION BY PIGEONS - PREFERENCE FOR LARGER, MORE DELAYED WORKREQUIREMENTS

In three experiments, pigeons chose between alternatives that required the completion of a small ratio schedule early in the trial or a larg er ratio schedule later in the trial. Completion of the ratio requirem ent did not lead to an immediate reinforcer, but simply allowed the ev ents of the trial to continue. In Experiment 1, the ratio requirements interrupted periods in which food was delivered on a variable-time sc hedule. In Experiments 2 and 3, each ratio requirement was preceded an d followed by a delay, and only one reinforcer was delivered, at the e nd of each trial. Two of the experiments used an adjusting-ratio proce dure in which the ratio requirement was increased and decreased over t rials so as to estimate an indifference point-a ratio size at which th e two alternatives were chosen about equally often. These experiments found clear evidence for ''procrastination''-the choice of a larger bu t more delayed response requirement. In some cases, subjects chose the more delayed ratio schedule even when it was larger than the more imm ediate alternative by a factor of four or more. The results suggest th at as the delay to the start of a ratio requirement is increased, it h as progressively less effect on choice behavior, in much the same way that delaying a positive reinforcer reduces it effect on choice.