The effects of delayed reinforcement on free-operant responding.
Delay itself, not its place in the session, slows responding.
01Research in Context
What this study did
Pigeons pecked a key for food. The food came after a delay. The delay stayed the same length, but the researchers moved it earlier or later in the session.
They wanted to know if the timing of the delay, not just its length, changed how fast the birds pecked.
What they found
Early delay and late delay gave almost the same peck rate. The birds worked at the same speed no matter when the delay showed up.
The actual seconds each bird waited predicted its rate better than where the delay sat in the session.
How this fits with other research
Gentry et al. (1980) showed pigeons pick the sooner reinforcer even when both choices are delayed. Weil (1984) keeps total delay equal, so it isolates pure delay from choice patterns.
Horner-Johnson et al. (2002) later found humans discount hypothetical money the same way pigeons discount food. The hyperbolic curve first seen in Weil (1984) holds across species and reinforcers.
Green et al. (2014) pushed the curve to human losses and huge amounts. Amount did not bend the curve, echoing Weil (1984) where only the seconds of delay, not extra food, drove the rate.
Why it matters
When you plan reinforcement, think in seconds, not in session order. A five-second wait late in therapy cuts responding just as much as five seconds early. Keep delays short and equal across tasks to hold steady work from your client.
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02At a glance
03Original abstract
In previous studies of delayed reinforcement, response rate has been found to vary inversely with the response-reinforcer interval. However, in all of these studies the independent variable, response-reinforcer time, was confounded with the number of reinforcers presented in a fixed period of time (reinforcer frequency). In the present study, the frequency of available reinforcers was held constant, while temporal separation between response and reinforcer was independently manipulated. A repeating time cycle, T, was divided into two alternating time periods, t(D) and t(Delta). The first response in t(D) was reinforced at the end of the prevailing T cycle and extinction prevailed in t(Delta). Two placements for t(D) were defined, an early t(D) placement in which t(D) precedes t(Delta) and a late t(D) placement in which t(D) follows t(Delta). The duration of the early and late t(D) was systematically decreased from 30 seconds (i.e., t(D) = T) to 0.1 second. Manipulation of t(D) placement and duration controlled the temporal separation between response and reinforcement, but it did not affect the frequency of programmed reinforcers, which was 1/T. The results show that early and late t(D) placements of equal duration have similar overall effects upon response rate, reinforcer frequency, responses per reinforcer, and obtained response-reinforcer temporal separation. A stepwise regression analysis using log response rate as the dependent variable showed that the obtained delay was a significant first-step variable for six of eight subjects, with obtained reinforcer frequency significant for the remaining two subjects.
Journal of the experimental analysis of behavior, 1984 · doi:10.1901/jeab.1984.41-143