Stimulus control and response bias in an analogue prey-detection procedure.
Reinforcement rules drive detection accuracy and bias; timeout duration is mostly noise.
01Research in Context
What this study did
Three pigeons pecked a key when they saw a faint line on a screen. Sometimes the line was there, sometimes not. The birds had to decide: peck left for 'yes, line' or right for 'no line'.
Correct choices earned food. Wrong choices turned on a timeout light for 2, 4, or 8 seconds. The team also ran a prey-analog version where errors meant no food instead of a timeout.
What they found
Longer timeouts barely changed the birds' accuracy or bias. Switching from food-loss to no-food had a bigger effect than any timeout length.
The prey-analog setup made the data jump around more, but still no clear timeout pattern emerged.
How this fits with other research
Kelly (1973) showed that paying more for certain response times shifts the whole timing pattern. P et al. echo this: the payoff rule matters more than the penalty length.
Udhnani et al. (2025) later found humans pick rules tied to richer payoffs. The same logic appears here: pigeons adjust to what earns food, not to how long the lights stay dark.
Renne et al. (1976) split stimulus control between visual and auditory cues under different contingencies. P et al. extend that idea by showing contingency type again beats timeout size in steering choice.
Why it matters
When you design a discrimination task, spend your effort on the reinforcement schedule, not on tweaking timeout minutes. If a child blurts out during DTT, adding 30 extra seconds of quiet time probably won't sharpen future discriminations. Instead, check what the correct response earns and whether the error simply misses reinforcement or triggers a real loss. Shift those contingencies first; keep timeout length short and consistent.
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02At a glance
03Original abstract
The present study compared the performance of 6 pigeons trained to detect luminance differences in two different signal-detection procedures. Exposed to a three-key array, the pigeons were trained to peck the left key when the brighter of two light intensities had been presented on the center key and to peck the right key when the dimmer of two light intensities had been presented on the center key. Procedure A was a standard signal-detection procedure in which left/bright and right/dim responses produced food reinforcement and left/dim and right/bright responses produced periods of timeout. Procedure B was designed to simulate some of the contingencies operating in a prey-detection situation. Left-key responses produced reinforcement following the brighter center-key stimulus and a period of timeout following the dimmer center-key stimulus. Right-key responses always produced a short period of timeout irrespective of the stimulus. Within each procedure, the duration of timeout arranged for false alarms (left/dim responses) was varied between 3 s and 120 s. Measures of accuracy and response bias were compared between the two procedures. The timeout manipulation produced systematic, but relatively small, changes in these measures when right/dim responses (i.e., correct rejections) produced reinforcement (Procedure A). Arranging timeout for right/dim responses in Procedure B produced greater variability in accuracy and response bias than did arranging reinforcement, but this variability was not related to timeout duration. Overall, discrimination accuracy was considerably higher when right/dim responses produced timeout than when they resulted in reinforcement, and accuracy was accompanied by a large bias toward the response associated with reinforcement. These results are consistent with a recently proposed model of signal detection.
Journal of the experimental analysis of behavior, 1993 · doi:10.1901/jeab.1993.60-387