Davison, M., & Jones, B. M. (1997).
Residence time in concurrent foraging with fixed times to prey arrival.
Journal of the Experimental Analysis of Behavior,
67, 161-179.
Five pigeons were trained in a concurrent foraging procedure in
which reinforcers were occasionally available after fixed times
in two discriminated patches. In Part 1 of the experiment, the
fixed times summed to 10 s, and were individually varied between
1 and 9 s over five conditions, with the probability of a
reinforcer being delivered at the fixed times always .5. In Part
2, both fixed times were 5 s, and the probabilities of food
delivery were varied over conditions, always summing to 1.0. In
Parts 3 and 4, one fixed time was kept constant (Part 3, 3 s;
Part 4, 7 s) while the other fixed time was varied from 1 s to 15
s. Median residence times in both patches increased with
increases in the food-arrival times in either patch, but
increased considerably more strongly in the patch in which the
arrival time was increased. However, when arrival times were very
different in the two patches, residence time in the longer
arrival-time patch often decreased. Patch residence also
increased with increasing probability of reinforcement, but again
tended to fall when one probability was much larger than the
other. A detailed analysis of residence times showed that these
comprised two distributions, one around a shorter mode that
remained constant with changes in arrival times, and one around a
longer mode that monotonically increased with increasing arrival
time. The frequency of shorter residence times appeared to be
controlled by the probability of, and arrival time of,
reinforcers in the alternative patch. The frequency of longer
residence times was controlled directly by the arrival time of
reinforcers in a patch, but not by the probability of reinforcers
in a patch. The environmental variables that control both staying
in a patch and exiting from a patch need to be understood in the
study both of timing processes and of foraging.
Key words: foraging, residence time, choice, reinforcer value,
scalar expectancy, key peck, pigeons