Behavioral contrast: what is it and how can it be used in Psychology?
Behavioral contrast is a concept of behaviorism that can be used to facilitate learning.
Within operant conditioning, behavioral contrast is a phenomenon in which a subject's behavior is increased or reduced after a change in operant schema is introduced after having introduced a change in operant schema that had been taught in previous trials.
This phenomenon can be useful in different contexts, especially in education and behavioral research, aspects that we will see more in 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 modification of one of the components in multiple operant reinforcement discrimination training. It can also be defined as the phenomenon that occurs when a change in the magnitude or frequency of a reinforcer is introduced that causes parameters to change that causes parameters related to the execution of a behavior, such as latency, frequency, accuracy and intensity, to be modified.
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 is increased (e.g., more 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 to be expected that the subject's behavior will worsen, he/she will perform fewer executions or will be less intense.
For example, let us suppose that 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, no matter what color the button is, the pigeon will always receive the food.The pigeon will receive the food as long as it presses one of the two buttons, i.e., the color is not associated with the reward, but the fact of pressing one of the two buttons.
However, as the experiment progresses, and seeing that the animal has associated the pressing of a button with the food, a change is introduced. Now, when the green button is clicked, the pigeon receives food less frequently than before, while the red button continues to provide as much food as before. Two situations could arise in response to this change.
On the one hand, it could happen that the pigeon, seeing that the button brings food but less frequently, starts to press it more times. If before one peck was enough to get the prize, now it needs five to get the same result, something that forces the pigeon to click the green button more times than before.This forces her to click the green button more times than before and, therefore, there is an increase in the emission rate of the same behavior.
However, on the other hand, it is quite likely that the pigeon reduces its rate of pecking on the green button and increases 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 effectIn this case we would have a negative contrast effect, since the pigeon has reduced its behavior with the green button because the green button has stopped rewarding it so often, while it pecks 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 speed, since the greater the reward, the faster the rodents seemed to run.
Seeing this supposed correlation the researcher opted to introduce a change. He took some rats that had been trained on circuits with lots of food at the end of the alley and moved them to circuits where less food was to be found. He did the same with some rats that had been trained on circuits with little food, now moving them to circuits with higher rewards..
Crespi saw that the rats that had originally been trained with the most food, when they were in a low-reward circuit, ran slower, even slower than the control rats in the same type of low-reward circuit that had not been moved anywhere. Similarly, rats transferred from low-reward to high-reward circuits now ran very fast, even faster than the control subjects.
With his 1942 experiments Crespi had just come upon the negative contrast effect and the positive contrast effectrespectively. Originally this researcher did not call the behavioral contrast effect thus, but preferred to speak of behavioral depression and behavioral elation. However, in 1949 David Zeaman suggested that a new nomenclature be used for these purposes, and he is credited with the names negative behavioral contrast and positive behavioral contrast.
Negative contrast and positive contrast and educational utility
The negative contrast effect is shown to be evident in operant conditioning when an attempt is made to reinforce a particular behavior by means of reward and then the reward is eliminated or reduced. This produces a situation in which the subject, who had previously been rewarded for performing behavior X, now does not receive such a reward, which does not motivate him as much to perform 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, the subject comes to understand it as a kind of "work". In the same way that in the job position we do not pretend 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 performing the behavior because it no longer benefits him..
This phenomenon can be useful to us in everyday life, especially in education. While giving children rewards to motivate them is a good strategy, giving them rewards every time they read a book, for example, can be counterproductive. At first they will read many books, motivated by receiving their reward (e.g., their favorite food). If we decide to remove the reward, confident that the child has acquired the habit of reading, we run the risk that he will stop reading, since it may happen that he has been doing it all this time to get the reward and if he does not get it now he does not 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 before, this effect occurs when the reward is increased or its frequency of occurrence is greater, causing the subject to perform 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 perform more times a behavior that is desirable to us.
In relation 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 acquires the habit of reading on his own, it is clear that this strategy will increase the number of books read, making him more skilled in reading.
Whatever the purpose for which we want to apply the behavioral contrast, the truth is that well used it is a phenomenon that can be beneficial to initiate behavioral change in someone. Its application in both laboratory and educational contexts is something that can certainly be very useful both to eradicate a certain behavior and to encourage any behavior that we wish.
(Updated at Mar 28 / 2023)