Positive and negative behavioral contrast in the rat.
Behavioral contrast appears in rats just like in pigeons, and the size of the swing grows with longer baseline history.
01Research in Context
What this study did
Rincover et al. (1975) worked with rats in standard cages.
They switched the amount of food given in different parts of the session.
The team watched how fast the rats pressed a lever after each switch.
What they found
When food suddenly got better, lever pressing shot up.
When food got worse, pressing dropped below the old level.
These jumps are called positive and negative behavioral contrast.
The longer the rats had stable food before the switch, the bigger the jump.
How this fits with other research
Hall (1992) extends this work. That study added extra lights that told the rats food was coming. The lights partly blocked contrast, showing that new signals can compete with the effect you expect.
Flapper et al. (2013) used the same rat setup but changed flash rate instead of food rate. Both studies prove that rat behavior is a clean window for basic operant principles.
Brown et al. (2025) also ran rats in cages. They found that rare stimuli are hard to learn. Together with Rincover et al. (1975), the pair warns that both stimulus rarity and reward change can swing responding in opposite ways.
Why it matters
Behavioral contrast is not just a pigeon curiosity. Rats show it too, so the rule crosses species. When you shift reinforcement in a client’s program, expect a brief swing in the opposite direction. Build extra baseline days if you need a strong effect, and watch for any new cues that might wash the contrast out.
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02At a glance
03Original abstract
Three groups of rats received either 8, 23, or 53 sessions of multiple variable-interval variable-interval baseline training before being shifted to a multiple extinction variable-interval schedule. The rate of responding during the unaltered component was higher for the groups shifted to multiple extinction variable-interval than for control groups remaining on multiple variable-interval variable-interval (positive contrast). Furthermore, when the multiple variable-interval variable-interval schedule was re-instated, stable negative contrast was found in the groups that had received 23 or 53 baseline sessions, but not for the group that had received only eight sessions. Positive and negative contrast were also demonstrated in the eight and 23-session groups when the multiple extinction variable-interval and multiple variable-interval variable-interval schedules were re-administered in further phases of the experiment. These results suggest that both positive and negative behavioral contrast can be obtained reliably in a species other than the pigeon.
Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.23-377