Contrast as seen in visual search reaction times.
Boosting reinforcement for one stimulus can immediately slow responses to its alternative, even in a simple visual search.
01Research in Context
What this study did
Pigeons played a video game. They had to find a colored dot on a screen and peck it fast.
Sometimes the dot paid three pellets, sometimes none. The schedule flipped every few minutes.
The scientist timed each peck to see if richer payoff for one color slowed the bird down to the other color.
What they found
When the red dot paid big, birds hesitated on the green dot. Their reaction time grew.
As soon as the pay switched, the slow-down flipped too. Green became fast, red became slow.
The effect was instant and repeated every flip, a clear contrast signature in a brand-new task.
How this fits with other research
Ginsburg et al. (1971) showed that longer extinction stretches make later contrast bigger. The 1989 task proves the same principle works in milliseconds, not minutes.
Neisworth et al. (1985) took the CRF/EXT swing to humans with ID and cut self-stimulatory behavior. The pigeon data give you the clean mechanism behind that clinical drop.
Van Houten et al. (1980) found that key-peck duration stayed unchanged during contrast. The new paper shows reaction time can change even when duration does not, so topography and speed are separate levers.
Why it matters
You now know that payoff for one target can instantly slow responding to its alternative in any discrimination task. Use this when you design visual schedules, matching games, or token boards. If a child earns big tokens for math facts, watch for slower reading answers right after. You can plan brief extinction probes or rotate high-pay items to keep both skills quick.
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Join Free →Track response time to the non-reinforced S during your next matching-to-sample trial; if it lags, briefly equalize reinforcement to reset speed.
02At a glance
03Original abstract
Three pigeons searched arrays of alphabetic letters displayed on computer monitors. On each trial, either an A or an E appeared, and the reaction time and accuracy with which the bird pecked at this target were measured. In each block of trials, each target (A or E) was displayed alone, or together with a number of distractor letters (2 or 18) that varied in their similarity to the target. During a baseline series of sessions, responses to the A and to the E each yielded food reinforcement on 10% of the trials. In the next series of sessions, reinforcement continued at 10% for A, but rose to 30% for E. In a final series, these reinforcement conditions were reversed. As expected, reaction times increased with target-distractor similarity and (for similar distractors) with the number of distractors. Increased reinforcement of E had no effect on reaction times to E, but produced a very consistent increase in reaction times to A; the average increase was constant across the various display conditions. Reversal of the differential reinforcement conditions reversed this contrast effect. Analysis of the reaction time distributions indicated that increased reinforcement to E decreased the momentary probability of response to A by a constant amount, regardless of display conditions. These results are discussed in relation to theories of contrast, memory, and of the search image.
Journal of the experimental analysis of behavior, 1989 · doi:10.1901/jeab.1989.52-199