What is a discriminative stimulus?

Our behavior is guided by the signals we perceive in the environment. The discriminative stimulus is one of those signals that tells us when we can act to obtain positive consequences. Find out what it is.

Written and verified by the psychologist Elena Sanz.

Last update: January 12, 2022

When they announce a radar on the road you know that you have to slow down. If you see a sign that says “WC” you know that by following it you will get to the bathroom. And if the traffic light is green you know you can cross. All of the above are examples of the discriminative stimulus; and, as you can see, they are very present in our day to day.

These stimuli are signals that we find in the environment and that help us regulate our behavior. They tell us when to proceed with certain behavior to obtain the desired consequences. If you want to know more about it, we invite you to continue reading.

The discriminative stimulus

Discriminatory encouragement helps us determine that the consequences of our actions could be positive.

To understand what a discriminative stimulus is, first it is necessary to talk about behavioral psychology. This current studies human behavior and understands it as the result of the relationship between stimuli and responses.

That is to say, all behavior is preceded by a stimulus and is followed by consequences. Based on these associations, a conditioning is created that modifies our way of behaving.

For example, If after issuing a certain response we receive a reward or avoid a punishment, we will learn to repeat that answer. Otherwise (by acting in a certain way we obtain negative consequences) we will reduce the frequency of emission of that response. This is what is called operant conditioning, a phenomenon studied by authors such as Skinner or Thorndike.



Now, what role does the discriminative stimulus play in this whole framework? Well, it’s the sign that tells us when we can act because at that time or place positive consequences are available.

For example, a “bakery” sign tells us that this is the establishment where we should buy bread. In any other place, (for example, a clothing store), our request will not have the desired response.

Thus, the discriminative stimulus does not cause us to emit or not a certain behavior, this depends on the consequences. But if signals when conditions are appropriate to do it.

Features and examples

The discriminative stimulus, then, is the signal that indicates the opportunity to respond. But this can be of a very diverse nature; from symbols, sounds or lights, to people, objects or environments.

Here are some examples of this so that you can get more clarity:

  • A rat is placed in a cage with a light bulb and a lever. Yes, when the light is green, you press the lever, you are offered food. If you do it when the light is off, this does not happen. The green light is in this case the discriminative stimulus.
  • When a child cries, his mother always attends and comforts him, but his father does not. The mother’s presence will become a discriminative stimulus That will indicate that the crying behavior is going to have the desired consequence at that time.
  • A speed camera tells us that, at that moment, reducing speed will bring us a positive consequence (avoiding a fine).
  • Seeing our partner in a good mood tells us that if we tell him a joke or make a joke at that moment, he will laugh and take it well. In other circumstances (for example, when she is irritated or angry) our behavior would not be reinforced.


Definitely, This stimulus helps us to discriminate at what times or to what elements the reinforcer is available. And we learn this because a certain behavior has been previously reinforced in the presence of said stimulus.

The discriminative stimulus and its relationship with the delta stimulus

While the discriminative stimulus warns of a possibly positive result, the delta stimulus indicates a possible negative result.

If the discriminative stimulus tells us that the reinforcer is available, the delta stimulus acts just the opposite: it tells us that our behavior will probably not follow the expected consequence.

For example, we are used to the fact that when we press the switch, the light turns on. But, if there is no current, no matter how much we press nothing will happen. Thus, the lack of electrical supply acts as a delta stimulus.

Another example could be that of a child who, when picking up toys in the presence of the teacher, receives praise and praise; but, if you do it in the presence of your peers, it is not reinforced. Thus, the teacher would be the discriminative stimulus (indicates the opportunity to act to obtain a reward) and the classmates the delta stimulus (in their presence, the positive consequence does not take place.

Stimulus control is present in our day to day

These concepts, which seem so theoretical and not very applicable to reality, certainly govern our daily behavior. If we did not learn to detect and attend to discriminatory stimuli, we would spend our time emitting useless and inappropriate behaviors. For example, trying to buy food at a stationery store or telling jokes in a serious work meeting.

Knowing how to differentiate when we will obtain positive consequences and when we will not guides our behavior and makes it more efficient and adapted. In addition, these behavioral methods are very useful in child rearing and in psychotherapy to modify inappropriate behaviors and establish more adaptive ones.

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