Jackson, K., & Hackenberg, T. D. (1996).
Token reinforcement, choice, and self-control in pigeons.
Journal of the Experimental Analysis of Behavior,
66, 29-49.
Pigeons were exposed to self-control procedures that involved
illumination of light-emitting diodes (LEDs) as a form of token
reinforcement. In a discrete-trials arrangement, subjects chose
between one and three LEDs; each LED was exchangeable for 2-s
access to food during distinct posttrial exchange periods. In
Experiment 1, subjects generally preferred the immediate
presentation of a single LED over the delayed presentation of
three LEDs, but differences in the delay to the exchange period
between the two options prevented a clear assessment of the
relative influence of LED delay and exchange-period delay as
determinants of choice. In Experiment 2, in which delays to the
exchange period from either alternative were equal in most
conditions, all subjects preferred the delayed three LEDs more
often than in Experiment 1. In Experiment 3, subjects preferred
the option that resulted in a greater amount of food more often
if the choices also produced LEDs than if they did not. In
Experiment 4, preference for the delayed three LEDs was obtained
when delays to the exchange period were equal, but reversed in
favor of an immediate single LED when the latter choice also
resulted in quicker access to exchange periods. The overall
pattern of results suggests that (a) delay to the exchange period
is a more critical determinant of choice than is delay to token
presentation; (b) tokens may function as conditioned reinforcers,
although their discriminative properties may be responsible for
the self-control that occurs under token reinforcer arrangements;
and (c) previously reported differences in the self-control
choices of humans and pigeons may have resulted at least in part
from the procedural conventions of using token reinforcers with
human subjects and food reinforcers with pigeon subjects.
Key words: choice, self-control, reinforcer amount, reinforcer
delay, token reinforcement, key peck, pigeons