Urcuioli, P. J., DeMarse, T. B., & Lionello, K. M. (1999).
Sample-duration effects on pigeons' delayed matching as a function of predictability of duration.
Journal of the Experimental Analysis of Behavior,
72, 279-297.
Three experiments assessed the impact of sample duration on
pigeons' delayed matching as a function of whether or not the
samples themselves signaled how long they would remain on. When
duration was uncorrelated with the sample appearing on each
matching trial, the typical effect of duration was observed:
Choice accuracy was higher with long (15-s) than with short (5-s)
durations. By contrast, this difference either disappeared or
reversed when the 5- and 15-s durations were correlated with the
sample stimuli. Sample duration itself cued comparison choice by
some birds in the latter (predictable) condition when duration
was also correlated with the reinforced choice alternatives.
However, even when duration could not provide a cue for choice,
pigeons matched predictably short-duration samples as accurately
as, or more accurately than, predictably long-duration samples.
Moreover, this result was observed independently of whether the
contextual conditions of the retention interval were the same as,
or different from, those of the intertrial interval. These
results strongly support the view that conditional stimulus
control by the samples is partly a function of their conditioned
reinforcing properties, as determined by the relative reduction
in overall delay to reinforcement that they signal.
Key words: sample duration, duration predictability, delayed
matching, delay-reduction hypothesis, conditioned reinforcement,
key peck, pigeons