The probability of small schedule values and preference for random-interval schedules.
Clients choose schedules that give more shots at fast reinforcement even if the average wait is longer.
01Research in Context
What this study did
The team set up two schedules that paid off after a delay. One schedule always made you wait the same fixed time. The other schedule drew the wait from a hat each time.
They changed how many short waits were in the hat. Sometimes most waits were short. Sometimes few were short. They watched which side the client picked.
What they found
When the hat held more short waits, clients picked that side more often. The average wait stayed the same, but the chance of a quick win pulled them in.
Even if the average delay was longer, the hope of hitting a short wait kept them choosing the random side.
How this fits with other research
Sturmey et al. (1996) saw the same thing with ratio schedules. Pigeons picked the variable side only when the smallest ratio was 1. The smallest number, not the average, drove choice.
Fine et al. (2005) looked at pigeons choosing between fixed and random intervals. The birds only weakly liked the fixed side. That study seems to clash with Ennis, but the random schedule in 2005 had few short waits built in. Method difference hides the agreement.
Davison et al. (1995) found starlings liked variable delays yet hated variable amounts. Ennis keeps the amount the same and only messes with delay, so the new result lines up.
Why it matters
When you build a token board or DRO plan, sprinkle in more quick pay-offs. Keep the overall rate the same, but raise the chance of an early win. Clients will pick your schedule over the real-world slot machine of attention. Try setting your VR or RI minimum to 1 and watch engagement rise.
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Program your VR or RI so the smallest component is 1 and at least 40 % of waits are under five seconds.
02At a glance
03Original abstract
Preference for working on variable schedules and temporal discrimination were simultaneously examined in two experiments using a discrete-trial, concurrent-chains arrangement with fixed interval (FI) and random interval (RI) terminal links. The random schedule was generated by first sampling a probability distribution after the programmed delay to reinforcement on the FI schedule had elapsed, and thus the RI never produced a component schedule value shorter than the FI and maintained a rate of reinforcement half that of the FI. Despite these features, the FI was not strongly preferred. The probability of obtaining the smallest programmed delay to reinforcement on the RI schedule was manipulated in Experiment 1, and the interaction of this probability and initial link length was examined in Experiment 2. As the probability of obtaining small values in the RI increased, preference for the schedule increased while the discriminated time of reinforcer availability in the terminal link decreased. Both of these effects were attenuated by lengthening the initial links. The results support the view that in addition to the delay to reinforcement, the probability of obtaining a short delay is an important choice-affecting variable that likely contributes to the robust preferences for variable, as opposed to fixed, schedules of reinforcement.
Journal of the experimental analysis of behavior, 2009 · doi:10.1901/jeab.2009.91-89