Comparing preference and resistance to change in constant- and variable-duration schedule components.
Fixed-duration schedules create stronger habits and more resistance to change than variable ones, even when pay-offs match.
01Research in Context
What this study did
Researchers worked with pigeons in a lab. They set up two choices that led to the same amount of food.
One choice always ended after the same amount of time. The other choice ended after a random amount of time.
The birds picked which key to peck. The team watched which key the birds liked more and how long they kept pecking when food stopped.
What they found
The birds strongly preferred the key that always lasted the same time. They kept pecking that key longer when food was removed.
Even though both keys gave the same food rate, the steady schedule felt safer and the birds stuck with it.
How this fits with other research
Iwata (1993) showed birds look at the overall food rate when they can switch back and forth. Pilgrim et al. (2000) adds that schedule shape itself matters too.
Killeen (2023) pulls both ideas into one math rule: steady, rich schedules build strong habits that are hard to stop.
Grant (1989) found birds like pecking more than treadling. Pilgrim et al. (2000) shows schedule shape is another hidden driver of choice, just like response type.
Why it matters
Your client may cling to routines that look equal on paper. If the routine has a fixed length or fixed order, it could be stickier than a varied one. When you fade reinforcement, expect more resistance with steady schedules and plan extra prompts or thinner fades for those parts.
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02At a glance
03Original abstract
Two experiments explored preference and resistance to change in concurrent chains in which the terminal links were variable-interval schedules that ended either after a single reinforcer had been delivered (variable duration) or after a fixed period of access to the schedule (constant duration). In Experiment 1, pigeons' preference between the same pair of terminal links overmatched relative reinforcement rate when the terminal links were of constant duration, but not when they were of variable duration. Responding during the richer terminal link decreased less, relative to baseline, when response-independent food was presented during the initial links according to a variable-time schedule. In Experiment 2, all subjects consistently preferred a terminal link that consisted of 20-s access to a variable-interval 20-s schedule over a terminal link that ended after one reinforcer had been delivered by the same schedule. Results of resistance-to-change tests corresponded to preference, as responding during the constant-duration terminal link decreased less, relative to baseline, when disrupted by both response-independent food during the initial links and prefeeding. Overall, these data extend the general covariation of preference and resistance to change seen in previous studies. However, they suggest that reinforcement numerosity, including variability in the number of reinforcers per terminal-link entry, may sometimes affect preference and resistance to change in ways that are difficult to explain in terms of current models.
Journal of the experimental analysis of behavior, 2000 · doi:10.1901/jeab.2000.74-165