Delta stimulus in psychology: characteristics and examples

In the behavioral framework, A stimulus is a signal that influences the responses of an organism and its senses. In the environment there are different types, within which we find: discriminative, evocative, reinforcing, conditioned-unconditioned and delta stimulus (S-delta).

S-deltas get their name from being present at the time when a response is not reinforced. To understand it better, imagine that you go to a vending machine to buy candy and you notice that the products are marked with red and green lights. If the green light is on, it means the product is available; If the red one does it, it means that the candy is sold out.

In this example, the green light (discriminative stimulus) would generate a behavior: pressing the button to get the candy. On the other hand, red light (delta stimulus) would not trigger a response. Therefore, if it were red, you would be prevented from inserting money into the machine. Let’s dig deeper into this topic.

What is a delta stimulus?

According to Mallott and Kohler (2021), a delta stimulus is characterized because when its presence responses are not reinforced or punished. For example, the absence of friends for a child can be an S-delta, since without them he will not get reinforcement for certain behaviors. It would also be the presence of his parents, with whom he will sense that they will not reinforce some answers that his friends would make.

When we talk about there being no consequences, we are referring to the lack of any procedure or strategy capable of increasing (reinforcements) or decreasing (punishments) the frequency of the appearance of a behavior.

For operant conditioning, the perpetuation or extinction of a behavior depends on its consequences. In the case of S-delta, there is no association between the response and its consequences, since they are not present. The stimulus appears, but not the effect on the organism.

So that, delta stimuli increase the probability of inhibition of a response, while the organism does not anticipate a reinforcement if it does it or a punishment if it does not do it. If it served to anticipate that a certain action will have negative effects (a punishment) or positive effects (a reinforcement), then it would no longer be an S-delta, but a discriminative one.

Characteristics

Some of the most relevant characteristics of delta stimuli are those listed below:

They are not associated with any type of consequence. In their manifestation, the behavior does not receive reinforcement. They increase the probability that a response will not occur. They reduce the frequency of behaviors punished in their presence. They function as a signal that a specific response will not be issued. .

How are delta stimuli evident?

Since S-delta is often confused with other types of stimuli, we have compiled four examples that will help clear up doubts about it.

1. Understanding signs

A person notices an “Out of Service” sign when trying to enter a bathroom. The sign operates in this case as a delta stimulus.

2. Bad behavior

A child exhibits disruptive behaviors in the presence of his mother, but when he is with his grandmother he does not exhibit any of these behaviors. In this case, the grandmother is an S-delta, since no response is produced in front of her.

3. Learning

A child with his mother reviews a book on means of transportation because he learns to recognize those that travel by land. Every time he identifies them correctly, his mother hugs and kisses him; However, when he points out non-land transportation, his mother does not hug him, but she does not punish him either. In this case, transport other than land transport operates as S-delta.

4. Training

A pigeon trainer makes two cards: one red and one blue. If they peck at the red card, their behavior will be reinforced; not like that when they do it in the blue. At first, the pigeons will peck both cards, but eventually they will only peck on the one that triggers a reward (the red one). The blue card operates in this example as S-delta.

Link between delta and discriminative stimuli

A discriminative stimulus increases the probability that reinforced responses will occur in its presence. Thus, a discriminative stimulus tells the organism what behavior to reinforce or punish. That is, it signals the availability of a consequence for a particular behavior.

The rule followed for the control of operant behavior by discriminative stimuli is the following: an operant behavior will occur, with a high frequency, in the presence of a discriminative stimulus which in the past accompanied its appearance and established the occasion for its reinforcement.

Likewise, it can make a response happen less often in those cases where it accompanied its reduction and established the occasion for its punishment.

The relationship between a delta and a discriminative stimulus is best seen with an example. Imagine that when a discriminative stimulus (green light) is present, a response (eating) is reinforced. But, when it is not present, the response is not carried out or reinforced. The stimuli that are present when the behavior is not reinforced are deltas.

Consequently, The S-delta operate in the opposite direction to the discriminative ones, since the latter serve to warn that a behavior will be reinforced or punished, while the delta indicates that it will not be reinforced or punished as expected.

Don’t downplay delta stimuli

As we have seen, delta stimuli are signals that do not favor the reinforcement or punishment of a response. Ultimately, they function as a warning that nothing will happen next.

Now, although they operate in this way, they are no less important in our lives, since They are necessary for the actions we carry out in certain contexts. Thanks to them, we can know what to expect and what not to expect from our environment.

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