Human fixed-interval performance with concurrently programmed schedules: A parametric analysis.
Human fixed-interval performance can lock into persistent pause or constant-rate patterns that survive schedule changes—watch for history effects when designing reinforcement programs.
01Research in Context
What this study did
Pisacreta (1982) tested how adults press a lever when two schedules run at once. One schedule pays on fixed-interval time. The other pays on fixed-ratio count, DRL delay, or another rule.
Each person first learns one pair of schedules. Later the pair changes. The team watches whether old response habits survive the switch.
What they found
People fell into two camps. Some paused after every payoff, then pressed fast near the next payday. Others pressed at a slow, steady beat all through the interval.
Those styles stuck. Even when the second schedule vanished or flipped, the old pattern stayed. Past training, not the current rule, drove the next move.
How this fits with other research
Poppen (1972) saw the same split ten years earlier. Concurrent DRL kept FI rates high and flat. Concurrent FR slowed FI presses and added long pauses. The 1982 paper widens that map with more schedule mixes.
Timberlake et al. (1987) later added competition. Their humans also showed break-and-run FI patterns, proving the style holds even when points race against another person.
English et al. (1995) tried to copy the effect in rats. VR history raised their FI rates but never locked them into the human "steady press" or "long pause" look. The contradiction warns us: rat data may not stand in for human history effects.
Why it matters
When you set up a token board or point system, remember the client carries old rules in their muscles. If yesterday they earned tokens only after waiting, they may keep pausing today even after you switch to a ratio board. Probe early sessions for leftover timing habits and re-train if the pattern hurts progress.
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Join Free →Start a new program with a brief probe session: deliver the first few reinforcers on a simple fixed-interval 30s and note whether the client pauses or keeps steady pressing; use that baseline to decide if you need to overwrite an old timing habit.
02At a glance
03Original abstract
Young adults pressed a lever for points, exchangeable for money, programmed on concurrent schedules in which one component was a fixed-interval and the other component either a fixed-ratio (Experiment 1) or a differential-reinforcement-of-low-rate (Experiment 2). Two general patterns of fixed-interval responding, postreinforcement pause or constant rate, occurred in both experiments as a function of the parameter values of each component. Also patterns of interaction between the component schedules developed, in which responding or point delivery on one component appeared to be discriminative for responding on the other component. Once a pattern of responding was established, it tended to persist when the parameter values of the schedule were changed. On many schedules, subjects with an experimental history responded differently than did naive subjects, although certain schedule values were resistant to the history effects. The role of verbal strategies in mediating history effects was discussed.
Journal of the experimental analysis of behavior, 1982 · doi:10.1901/jeab.1982.37-251