Ito, M., & Nakamura, K. (1998).
Humans' choice in a self-control choice situation: Sensitivity to reinforcer amount, reinforcer delay, and overall reinforcement density.
Journal of the Experimental Analysis of Behavior,
69, 87-102.
Human subjects were exposed to a concurrent-chains schedule in
which reinforcer amounts, delays, or both were varied in the
terminal links, and consummatory responses were required to
receive points that were later exchangeable for money. Two
independent variable-interval 30-s schedules were in effect
during the initial links, and delay periods were defined by
fixed-time schedules. In Experiment 1, subjects were exposed to
three different pairs of reinforcer amounts and delays, and
sensitivity to reinforcer amount and delay was determined based
on the generalized matching law. The relative responding (choice)
of most subjects was more sensitive to reinforcer amount than to
reinforcer delay. In Experiment 2, subjects chose between
immediate smaller reinforcers and delayed larger reinforcers in
five conditions with and without timeout periods that followed a
shorter delay, in which reinforcer amounts and delays were
combined to make different predictions based on local
reinforcement density (i.e., points per delay) or overall
reinforcement density (i.e., points per total time). In most
conditions, subjects' choices were qualitatively in accord with
the predictions from the overall reinforcement density calculated
by the ratio of reinforcer amount and total time. Therefore, the
overall reinforcement density appears to influence the preference
of humans in the present self-control choice situation.
Key words: choice, self-control, sensitivity to reinforcer amount
and delay, overall reinforcement density, concurrent-chains
schedule, screen touch, humans