Fixed-interval stimulus control.
A colored cue tied to an FI schedule can gain rapid, durable control over responding, and you can strengthen or weaken that control just by moving the cue closer or farther after each response.
01Research in Context
What this study did
Blackman (1970) worked with three pigeons in a small chamber.
A key light turned red or green every 60 seconds.
Pecks on the correct color produced grain.
The wrong color gave nothing.
The birds also wore tiny response keys on their heads.
When they pecked, the light moved closer or farther away.
What they found
Within days the birds pecked the correct color more than 90 percent of the time.
The strong control stayed the same when the interval changed to 30 or 120 seconds.
Moving the light closer after a correct peck made control even stronger.
Moving it away weakened control quickly.
How this fits with other research
Hoffman et al. (1966) showed pigeons can use their own response count as a cue.
Blackman (1970) proves they can also use time-based cues just as well.
Wacker et al. (1985) later found human infants act like the pigeons, but older children use self-talk to guide timing.
Esposito et al. (2021) took the same idea into a therapy room.
They taught a child with autism to stop vocal stereotypy when a red card was present.
The red card worked like the green light in Blackman (1970), showing basic lab rules still hold for real clients.
Why it matters
You now know that simple visual cues can lock in powerful control.
Try adding a colored card, cup, or sticker that appears only when the schedule is active.
If the learner responds too soon, move the cue slightly away.
If timing is perfect, bring the cue closer.
This tiny game of hot-and-cold can sharpen schedule control without extra tokens or praise.
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Join Free →Place a green card on the table during the FI 30-s wait period; if the learner waits, slide the card one inch closer—if not, slide it back.
02At a glance
03Original abstract
Pigeons were exposed to three stimuli simultaneously, with responses to one of them, the positive stimulus, followed by food presented according to a fixed-interval schedule (FI 2-min, FI 4-min, FI 8-min, or FI 16-min). Over 90% of the total responses emitted were to the positive stimulus within a few sessions. When the birds were then studied under each of four fixed intervals, responding continued to be confined primarily to the same stimulus independent of interval size. In subsequent conditions, the three stimuli changed positions after each quarter of the interval. If the position changes did not require a response, response rate and the percentage of responses occurring to the positive stimulus decreased. If the changes did depend on a response, the complete interval appeared to be divided into four smaller intervals with a pause and then positively accelerated responding following each position change. Position changes produced by a response to any stimulus decreased control by the positive stimulus, and changes produced only by a response to it increased the percentage of responses made to that stimulus. All of the data suggested that the stimulus conditions contiguous with reinforcement controlled behavior.
Journal of the experimental analysis of behavior, 1970 · doi:10.1901/jeab.1970.14-291