Hartl, J. A., & Fantino, E. (1996).
Choice as a function of reinforcement ratios in delayed matching to sample.
Journal of the Experimental Analysis of Behavior,
66, 11-27.
Pigeons were studied in two experiments using a delayed
matching-to-sample task. In Experiment 1, 4 subjects were exposed
to a task in which the proportion of reinforcement associated
with matching and nonmatching, and the overall proportion of
reinforcement associated with selecting each choice, r egardless
of the sample stimulus, were varied. Choice was sensitive to both
proportions. A least squares regression analysis showed that
Wixted's (1989) proportions of reinforcement model closely fit
the data from Experiment 1; however, the model failed to make
accurate qualitative predictions for some test conditions. In
Experiment 2, 4 subjects were exposed to a delayed
matching-to-sample task in which the retention intervals and the
reduction in delay to reinforcement signaled by the onset of the
sample stimulus were independently varied. When the retention
interval was short and when the delay-reduction value of the
sample stimulus was high, the sample exerted greater control over
choice; the control by the overall proportion of reinforcements
for selecting each choice stimulus was correspondingly low.
Conversely, when the retention interval was long and the
delay-reduction value of the sample stimulus was low, the sample
exerted relatively less control over choice; control by the
overall proportion of reinforcements obtained for selecting each
choice stimulus was correspondingly high. A signal detection
analysis found that sensitivity to reinforcement
varied directly with retention interval. Data were also
consistent with misallocation models. No evidence was found to
suggest that pigeons ignore the rate at which selecting
individual choice stimuli is reinforced, as has been reported in
studies with human subjects.
Key words: delayed matching to sample, base-rate error, retention
interval, choice, delay reduction, key peck,
pigeons