Effects of stimulus frequency and reinforcement variables on reaction time.
Reinforcement probability alone controls reaction time; stimulus frequency and reinforcer size do not.
01Research in Context
What this study did
The team worked with pigeons in a lab. Each bird pecked a key when a light came on.
The birds earned food on some trials. The chance of food stayed the same no matter how often the light appeared or how long the food lasted.
The scientists timed how fast the birds pecked after the light turned on.
What they found
Reaction time only changed when the chance of food changed. Making the light appear more often did nothing.
Giving bigger or smaller pieces of food also did nothing. Only the odds of getting food mattered.
How this fits with other research
STEBBINROSS et al. (1962) saw the same thing thirty years earlier. When food came more often, pigeons pecked faster. Both studies show that how often food shows up controls speed, not how big the food is.
Kohlenberg (1973) looked at food size too. That study found birds stopped looking if food size signals were too short. Blough (1992) now adds that food size does not touch reaction time at all. Together they tell us duration matters for watching, but not for speed.
Nevin et al. (2005) later showed that faster flashing lights made birds look more, yet the response did not get stronger. Blough (1992) matches this idea: rate changes speed, but other features do not.
Why it matters
When you shape a quick mand or a fast transition, do not worry about using a big versus small reinforcer. Focus on how often the reinforcer follows the target response. Keep the probability high at first, then thin the schedule once the speed is steady. This simple shift gives you faster responses without extra edibles or toys.
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02At a glance
03Original abstract
Pigeons pecked at one of two black forms, "+" or "O," either of which could appear alone on a white computer monitor screen. In baseline series of sessions, each form appeared equally often, and two pecks at it produced food reinforcement on 10% of trials. Test series varied the relative probability or duration of reinforcement or frequency of appearance of the targets. Peck reaction times, measured from target onset to the first peck, were found to vary as a function of reinforcement probability but not as a function of relative target frequency or of reinforcement duration. Reaction times to the two targets remained approximately equal as long as the probability of reinforcement, per trial, was equal for the targets, even if the relative frequency of the targets differed by as much as 19 to 1. The results address issues raised in visual search experiments and indicate that attentional priming is unimportant when targets are easy to detect. The results also suggest that equalizing reinforcement probability per trial for all targets removes differential reinforcement as an important variable. That reaction time was sensitive to the probability but not the duration of reinforcement raises interesting questions about the processes reflected in reaction time compared with rate as a response measure.
Journal of the experimental analysis of behavior, 1992 · doi:10.1901/jeab.1992.57-47