Behavioral contrast: what it is and how it can be used in psychology

Within operant conditioning, behavioral contrast is a phenomenon in which it is possible to increase or reduce the behavior of a subject after having introduced a change in operant schema that had been taught in previous essays.

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 a reinforcement multiple 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 that causes parameters related to the execution of a behavior to be modified, such as its latency, frequency, precision and intensity.

The behavioral contrast phenomenon is common within operant conditioning, especially in discrimination tasks with two or more responses. When the magnitude of the reinforcer is increased (eg, more food is given) or its frequency increases (eg, 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 one red. At the beginning of the training, it does not matter what the color of 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 the act of pressing one of the two buttons.

However, once the experiment has advanced 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 often than before, while the red button continues to provide as much food as before. Faced with 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, starts to press it more times. If before with one peck he was enough to receive the prize, now he needs 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, and on the other hand, it is quite probable that the pigeon reduces its pecking rate before the green button and increases it in the red button, since it is the one that continues to feed it 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 so often, while it pecks the other button more frequently even though it continues to give the same amount of feed as before.

Concept history

In 1942, Leo P. Crespi measured how fast rats ran in an alley-shaped circuit in which different amounts of food were eventually found. 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 speed, since the higher 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 high-food circuits 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 reward..

Crespi saw that rats that had originally been trained with the most food, when in a circuit with little reward, were slower, even slower than rats that were control in the same type of circuit with little food and that they had not been moved anywhere. Something similar happened with the rats moved from circuits with little reward to 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 way, but preferred to speak of behavioral depression and elation. However, in 1949 David Zeaman suggested that a new nomenclature be used for these effects, being the one who is attributed the names of negative behavioral contrast and positive behavioral contrast.

Behavioral contrast in children

Negative contrast and positive contrast and educational utility

The negative contrast effect is shown to be 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 a behavior X, now does not receive such a prize, which does not motivate him as much to emit the same behavior.

It has been suggested that behind the phenomenon of negative contrast what really happens is that, after having rewarded a behavior in the subject, be it animal or person, this comes to understand it as a kind of “work”. In the same way that in the job position 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 this award is removed, he will stop doing the behavior because it no longer benefits him.

This phenomenon can be useful to us in daily life, especially in the educational field. While giving children prizes to motivate them is a good strategy, giving them prizes every time they read a book, for example, can backfire. At first they will read many books, motivated by receiving their reward (eg, their favorite food). If we decide to suppress the award, 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 done it all this time to get the award and if he does not get it now he will not see the need to keep reading.

On the other hand, we can benefit from the positive contrast effect in education. 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, the subject to whom it is applied can feel motivated to emit more times a behavior that is desirable to us.

Relating it to the previous case, we can create a situation of positive behavioral contrast by doing that, 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. While it is desirable that you get into the habit of reading on your own, it is clear that this strategy will increase the number of books read, making you more proficient at reading.

Whatever the purpose for which you want to apply the behavioral contrast, the truth is that well used it is a phenomenon that can be beneficial to initiate the change of behavior in someone. Its application both in the laboratory context and in the educational field is something that of course can be very useful both to eradicate a certain behavior and to promote whatever we like.

Bibliographic references:

  • Mackintosh, NJ (1974) The Psychology of Animal Learning. New York: Academic Press
  • Catania, AC (1992) Learning. Englewood Cliffs NJ: Prentice-Hall
  • Crespi, Leo P. (1942). Quantitative variation of incentive and performance in the white rat. American Journal of Psychology, 55, 467-517
  • Zeaman, D. (1949). Response latency as a function of the amount of reinforcement. Journal of Experimental Psychology, 39, 466-483
  • Bower, GH, & Hilgard, ER (1980). Theories of Learning (5th ed.) Englewood Cliffs, NJ: Prentice-Hall
  • Flaherty, CF Incentive Relativity New York, NY: Cambridge University Press
  • Lattal, Kennon A., & Smith, Julie M .. (2011). Behavioral contrast when responses are maintained by unsignaled delayed reinforcement. Mexican Journal of Behavior Analysis, 37 (3), 7-18.

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