Tests of transitivity in choices between fixed and variable reinforcer delays.
Choice logic stays intact when delays, not amounts, are the only thing varied.
01Research in Context
What this study did
Six pigeons pecked two keys in a chamber. One key gave food after a fixed delay. The other key gave food after a variable delay.
The team switched the delay values many times. They checked if the birds’ choices stayed logical. A logical pattern is called transitive: if A is picked over B, and B over C, then A should be picked over C.
What they found
The birds’ choices stayed almost perfectly transitive. Tiny errors were too small to matter.
Variable versus fixed delays did not break the logic of their choices.
How this fits with other research
Fine et al. (2005) later saw weak, fading preference for fixed delays. That looks like a clash, but they used interval schedules, not time schedules, so the tasks differ.
Davison et al. (1995) showed starlings also like variable delays, extending the pigeon rule to a new species.
Doughty et al. (2010) added humans: both people and pigeons pick variable delays when tokens trade right away. The 1987 bird rule holds across species when procedures match.
Why it matters
Your clients’ choices should stay consistent if delays are the only thing changing. When you fade from fixed to variable reinforcement, expect smooth transfer instead of sudden reversals. Use this peace of mind to move from continuous to intermittent schedules without extra errors.
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Switch one program from fixed praise to variable praise and watch for stable responding.
02At a glance
03Original abstract
This experiment tested for transitivity in pigeons' choices between variable-time (VT) and fixed-time (FT) schedules. In a discrete-trials procedure, a subject chose between two alternatives by making a single key peck. Each choice was between a "standard alternative," which was the same schedule throughout a condition, and an "adjusting alternative," in which the delay to reinforcement was systematically increased or decreased many times a session. These adjustments enabled an approximate indifference point to be identified--the value of the adjusting delay at which the subject chose each alternative about equally often. Each test of transitivity involved four conditions. In one, the standard alternative was a variable-time schedule with a 2-s reinforcer, and the adjusting alternative also delivered a 2-s reinforcer. A second condition was similar except that the adjusting alternative delivered a 5-s reinforcer. The indifference point from each of these conditions was then converted to a fixed-time schedule for subsequent comparisons in the third and fourth conditions, respectively. Each of these last two conditions compared one of the fixed-time schedules (based upon the previous conditions and including their different reinforcer durations) with an adjusting schedule that delivered the alternative reinforcer duration, to determine whether the obtained indifference points would be those predicted from the prior alternative-duration comparisons with the VT schedule. There was little evidence for intransitivity of choice: Averaged across subjects and replications, the obtained indifference points deviated from perfect transitivity by less than 8%, and these deviations were not statistically significant. These results contrast with those of Navarick and Fantino (1972), who found frequent violations of transitivity between periodic and aperiodic schedules using a concurrent-chains procedure with variable-interval schedules in the initial links.
Journal of the experimental analysis of behavior, 1987 · doi:10.1901/jeab.1987.47-287