Mazur, J. E. (1996).
Procrastination by pigeons: Preference for larger, more delayed work requirements.
Journal of the Experimental Analysis of Behavior,
65, 159-171.
In three experiments, pigeons chose between alternatives that
required the completion of a small ratio schedule early in the
trial or a larger ratio schedule later in the trial. Completion
of the ratio requirement did not lead to an immediate reinforcer,
but simply allowed the events of the trial to continue. In
Experiment 1, the ratio requirements interrupted periods in which
food was delivered on a variable-time schedule. In Experiments 2
and 3, each ratio requirement was preceded and followed by a
delay, and only one reinforcer was delivered, at the end of each
trial. Two of the experiments used an adjusting-ratio procedure
in which the ratio requirement was increased and decreased over
trials so as to estimate an indifference point - a ratio size at
which the two alternatives were chosen about equally often. These
experiments found clear evidence for "'ocrastination" -
the choice of a larger but more delayed response requirement. In
some cases, subjects chose the more delayed ratio schedule even
when it was larger than the more immediate alternative by a
factor of four or more. The results suggest that as the delay to
the start of a ratio requirement is increased, it has
progressively less effect on choice behavior, in much the same
way that delaying a positive reinforcer reduces it effect on
choice.
Key words: choice, ratio schedules, delay, procrastination, key
peck, pigeons