Behavioral contrast in competitive and noncompetitive environments.
Positive response jumps can come from two places—competition with other available acts or a pure rate lift—so always scan the setting for alternate options.
01Research in Context
What this study did
Burgio et al. (1986) worked with lab rats on a two-part lever schedule.
In one part the rats earned lots of food. In the other part food was scarce.
The team also gave the rats a water bottle and sometimes made them thirsty. They wanted to see if the animals would drink more when lever pressing suddenly paid better.
What they found
When the rich schedule started, lever pressing jumped up. That is classic positive contrast.
Some rats drank more, others did not. Thirst and bottle presence decided which rats switched to drinking.
The authors say two engines sit behind the jump: a competitive one (lever vs drink) and a non-competitive one (pure rate increase).
How this fits with other research
White (1978) saw the same rate jump but said it was just smart time use. D et al. add the idea that rats may also fight between topographies like lever and drink.
Allison (1976) used conservation theory: reward one act, the other drops. D et al. keep the math but split the rise into two paths instead of one.
Mace et al. (1990) later moved the logic to adults with ID sorting dishes. Higher payoff schedules, not the act itself, kept them working when noise hit. The dual-mechanism idea travels from rats to people.
Why it matters
When a client’s target responses suddenly rise, do not assume the reinforcer alone did it. Ask what else the client could be doing. If water, toys, or escape are handy, the jump may be competitive. If no alternatives show up, the jump is non-competitive. Check the surroundings before you pick an intervention.
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02At a glance
03Original abstract
Three experiments examined the effects of opportunities for an alternative response (drinking) on positive behavioral contrast of rats' food-reinforced bar pressing. In both Experiments 1 and 2 the baseline multiple variable-interval schedules were rich (variable interval 10-s), and contrast was examined both with and without a water bottle present. In Experiment 1, the rats were not water deprived. When one component of the multiple schedule was changed to extinction, the rate of bar pressing increased in the constant component (positive behavioral contrast). The magnitude of contrast was larger when the bottle was absent than when it was present, as predicted by the matching law. Drinking did not shift from the constant variable-interval component to the extinction component, as might have been expected from competition theory. In Experiment 2, the rats were water deprived. Contrast was larger when the bottle was present than when it was absent, and drinking did shift to the extinction component, as predicted by competition theory. In Experiment 3, water-deprived rats responded on leaner multiple variable-interval schedules (60-s) in the presence of a water bottle. When one component was changed to extinction, contrast did not occur, and drinking did not shift to the extinction component. The present results suggest that there are at least two different sources of behavioral contrast: "competitive" contrast, observed when an alternative response occurs with high probability, and "noncompetitive" contrast, observed when an alternative response occurs with low probability. The results, in conjunction with earlier studies, also suggest that the form of the alternative response and the rate of food reinforcement provided by the multiple schedule combine to determine the amount of contrast.
Journal of the experimental analysis of behavior, 1986 · doi:10.1901/jeab.1986.46-185