Behavioral Contrast: What It Is And How It Can Be Used In Psychology

Behavioral contrast

Within operant conditioning, Behavioral contrast is a phenomenon in which the behavior of a subject is increased or reduced after having introduced a change in the operant scheme that had been taught in previous trials.

This phenomenon can be useful in different contexts, especially educational and behavioral research, aspects that we will see in more depth below.

Behavioral contrast: what is it?

Behavioral contrast, also called negative contrast effect and positive contrast effect, is the change in response rate or response latency after modifying one of the components in multiple reinforcement operant discrimination training. It can also be defined as the phenomenon that occurs when a change is introduced in the magnitude or frequency of a reinforcer which causes parameters related to the execution of a behavior to be modified, such as its latency, frequency, precision and intensity.

The phenomenon of behavioral contrast is common within operant conditioning, especially in discrimination tasks with two or more responses. When the magnitude of the reinforcer is increased (e.g., more food is given) or its frequency increases (e.g., food is given more times), in principle, the performance of the behavior improves, increases and/or is more intense. On the other hand, if the magnitude is reduced or its frequency is lower, it is expected that the subject’s behavior will worsen, perform fewer executions or be less intense.


For example, suppose we have a pigeon inside an operant conditioning chamber and that to receive the reward (food) it must press one of the two buttons, one green and the other red. At the beginning of the training it does not matter what color the button is the pigeon will receive the food as long as it presses one of the two, that is, the color is not associated with the prize, but rather the fact of pressing one of the two buttons.

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However, as the experiment progresses and seeing that the animal has associated pressing a button with food, a change is introduced. Now, by clicking the green button, the pigeon receives food less frequently than before, while the red button continues to provide as much food as before. Given this change, two situations could arise.

On the one hand, it could happen that the pigeon, seeing that the button brings food with it but less frequently, begins to press it more times. If before one peck was enough to receive the prize, now it takes five to obtain the same result something that forces her to click the green button more times than she did before and, therefore, there is an increase in the rate of emission of the same behavior.

However, on the other hand, it is quite likely that the pigeon will reduce its pecking rate on the green button and increase it on the red button, since it is the one that continues to give it food constantly. In this case we would have a negative contrast effect since the pigeon has reduced its behavior with the green button because it has stopped rewarding it as often, while it pecks at the other button more frequently even though it continues to give the same amount of food as before.

History of the concept

In 1942, Leo P. Crespi measured how fast rats ran in an alley-shaped circuit with different amounts of food at the end. There were rats that received a lot of food, while others received little. The researcher observed that the amount of food found at the end of the circuit seemed to influence the speed, since the greater the reward, the faster the rodents seemed to run.

Seeing this supposed correlation, the researcher chose to introduce a change. He took some rats that had been trained in the circuits with a lot of food at the end of the alley and moved them to circuits where less food was found. He did the same with some rats that had been trained in circuits with little food, now moving them to circuits with higher rewards

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Crespi saw that the rats that had originally been trained with the highest amount of food, when they were in a circuit with little reward, were slower, even more so than the rats that acted as controls in the same type of circuit with little food and that They had not been moved anywhere. Something similar happened with the rats transferred from circuits with little reward to those with more reward, which now ran very fast, even faster than the control subjects.

With his 1942 experiments, Crespi had just come across the negative contrast effect and the positive contrast effect, respectively. Originally this researcher did not call the behavioral contrast effect that, but preferred to talk about behavioral depression and elation. However, in 1949 David Zeaman suggested that a new nomenclature be used for these effects, to whom the names negative behavioral contrast and positive behavioral contrast are attributed.

Behavioral contrast in children

Negative contrast and positive contrast and educational utility

The negative contrast effect is evident within operant conditioning when an attempt is made to reinforce a particular behavior through reward and then the reward is eliminated or reduced. This produces a situation in which the subject, who had previously been rewarded for emitting behavior X, now does not receive such a reward, which does not motivate him as much to emit that same behavior.

It has been suggested that what really happens behind the phenomenon of negative contrast is that, after having rewarded a behavior in the subject, be it animal or person, he or she comes to understand it as a kind of “work.” In the same way that in the workplace we do not intend to work without receiving something in return, after having made the experimental subject associate a stimulus with performing a behavior and receiving a reward, If such a reward is removed, he will stop doing the behavior because it no longer benefits him

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This phenomenon can be useful to us in daily life, especially in the educational field. While giving children treats to motivate them is a good strategy, giving them treats every time they, for example, read a book can be counterproductive. At first they will read a lot of books, motivated by receiving their reward (e.g., their favorite food). If we decide to eliminate the reward, confident that the child has acquired the habit of reading, we run the risk that he will stop doing it, since it may happen that he has been doing it all this time to get the reward and if he doesn’t get it now he won’t see the need to continue reading.

On the other hand, we can benefit from the positive contrast effect in the educational field As we mentioned, this effect occurs when the reward is increased or its frequency of appearance is greater, causing the subject to do the reinforced behavior more times or with greater intensity. If this strategy is applied properly, it can be achieved that the subject to whom it is applied feels motivated to emit a behavior that we find desirable more times.

Relating it to the previous case, we can create a situation of positive behavioral contrast by making, If the child shows us that he has increased the level of difficulty in his reading, instead of giving him his favorite food once, we give it to him twice Although it is desirable that he acquire the habit of reading on his own, it is clear that this strategy will increase the number of books read, making him more skilled at reading.

Whatever the purpose for which you want to apply the behavioral contrast, the truth is that used correctly it is a phenomenon that can be beneficial to initiate behavioral change in someone. Its application both in a laboratory context and in an educational setting is something that can certainly be very useful both to eradicate a certain behavior and to encourage any that we like.