Enhancement of conditioned reinforcement by uncertainty.
A little mystery makes tokens work harder.
01Research in Context
What this study did
Schwartz (1975) tested how uncertainty changes conditioned reinforcement. Pigeons pecked a key for tokens. Some tokens always bought food. Some tokens only sometimes bought food. The team counted pecks under each rule.
They ran three phases: baseline with no tokens, certain tokens, and uncertain tokens. Each phase lasted many sessions. They tracked response rate minute by minute.
What they found
Birds pecked fastest when tokens were uncertain. Response rate dropped under certain tokens. It dropped even lower in baseline.
In plain words, maybe is more powerful than yes. The unsure payoff made the token a stronger reinforcer.
How this fits with other research
Vergason et al. (2020) moved the same idea to a zoo. Staff got tokens from guests at random times. Greeting scores jumped about 40%. The lab finding holds in the real world.
Goldman et al. (2022) used uncertain tokens to get kids with autism moving. Two of four children showed higher activity. The principle crosses diagnoses and species.
WERTHEIWENZEL et al. (1964) looked at fish under fixed versus variable pay. Variable pay kept fish swimming longer during extinction. Both studies show that not knowing keeps behavior alive.
Why it matters
You can juice up any token board by adding surprise. Hand out tokens on a loose schedule. Swap the backup reinforcer now and then. Keep the learner guessing and the clicks or stickers stay powerful. Start small: give five tokens, then three, then seven, while praise stays loud. Watch the work rate rise.
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02At a glance
03Original abstract
Pigeons were trained in three conditions. In the baseline condition, the birds responded on a fixed-interval schedule with the response key white. When the interval was completed, the key turned either red or green for a delay interval that was terminated by a grain presentation dependent on no key pecks during the final 2 sec. In the uncertainty condition, no grain was presented at the end of the delay periods when the key was red. In the certainty condition, the white light appeared only on occasions when pecking would turn the key green and produce food. Otherwise, the key was illuminated red throughout the total time period. The highest response rate in white occurred in the uncertainty condition, the next highest in the certainty condition, and the lowest in baseline. The results suggest that uncertainty facilitated responding, although uncertainty is not a necessary condition for conditioned reinforcement.
Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.24-311