Overshadowing: what is it and how is it used in classical conditioning?

Overshadowing is a phenomenon associated with Pavlovian conditioning. Let's see how it works.

In psychology, most of the behavioral phenomena described by this science have to do with learning.

Shadowing is one of the concepts that refer to how we learn through classical conditioning. through classical conditioning, and in this article we will see what it consists of. Let's start with the basics.

What is classical conditioning?

Basic psychology explains, describes and defines the laws that govern the organism, understanding it as behavior, and the processes underlying it. Within it, we find the psychology of learning and, more specifically, classical conditioning.

Classical conditioning (CC) or Pavlovian conditioning is a central theme in the psychology of learning, as well as one of its basic principles.

This type of learning involves automatic or reflex responses, not voluntary behaviors (in this it differs (in this it differs from operant or instrumental conditioning).

CC consists in the creation of a connection between a new stimulus and an already existing reflex; it would be, therefore, when an originally neutral stimulus, which does not elicit a response, comes to elicit a response thanks to the associative connection of this stimulus with the stimulus that normally elicits such a response.

CC makes it possible to teach children to perform desired behaviors by associating stimuli with other stimuli by associating stimuli with other unconditioned stimuli that already generate the target behavior in the child (e.g., associating a bell (EC) with the fact of starting recess (EI), so that children get ready to go out to the playground when they hear the bell.

This type of learning will allow the establishment of routines that help children to anticipate the behaviors they have to perform. Of vital importance is this learning when working with children who have special educational needs, as these routines prevent disorientation and the appearance of anxiety.

Shadowing: the importance of salience

From classical conditioning we can differentiate different complex phenomena. One of them is overshadowing..

This was initially described by Ivan Pavlov in 1927, and consists of the joint presentation of two stimuli that differ in salience (saliency) followed by an unconditioned stimulus (EI).

This sequence implies a conditioned response (CR) of greater intensity to the more salient stimulus. Thus, if A is more salient than B, it will be conditioned more quickly than B, and it will also make the conditioning of B more difficult. will hinder the conditioning of B.

Thus, the more the EC stands out from the rest of the stimuli present during acquisition (which may be one or several), the better the conditioning.

Shadowing experiments

A typical shadowing experiment would include two groups of subjects and two stimulus items, one of high intensity (A) and one of low intensity (b).

For the shadowing group, the two stimuli are presented together (Ab) as a paired composite cue. a compound cue and paired with reinforcement during conditioning.. For the control group, only the low-intensity stimulus (b) is presented during conditioning.

Tests are conducted for each group presenting only the weakest element of the stimulus (b). These tests show a lower number of responses (RC's) to b in the shading group than in the control group.

Thus, it is observed how the presence of A alters behavioral control by the weakest stimulus, b. In more precise terms, we will say that A has subtracted B's power of association with the reinforcer.

But, what are the characteristics of salience? One of them would be the intensity of the stimulus, and, although there are others, for research purposes we neutralize the other variables that determine salience and only vary the intensity.

Thus, by logic, of two environmental elements (neutral stimuli) paired with EI, we will pay more attention to the more salient one, the one that attracts our attention the most.and this will lead to a greater conditioned response.

An example

We can think of an example to visualize this type of procedure; traffic signs.

A sign painted on the ground will be less salient than a sign on a pole, and will therefore be less effective. In this case, the saliency will also have to do with the location of the sign and our position while driving (the sign on the pole will be more visible to us, more conspicuous).

In addition, we know that the sign on a pole takes precedence over a painted sign in the dream, in case we encounter a contradiction between the two.

Differences between shadowing and blocking

We must not confuse shadowing with a similar but not identical phenomenon, the blocking effect.

This is also a phenomenon of classical conditioning.The blocking effect is that a conditioned stimulus (EC1) is paired with an unconditioned stimulus (EI) in a first phase, and in a second phase both EC1 and a new conditioned stimulus (EC2) are paired together with the EI; all this causes the learning of EC2 to be hindered.

That is, the conditioning of a first EC (EC1) hinders the learning of a second EC (EC2) later on.

Thus, we see that in both shadowing and blocking, one stimulus causes another stimulus to lose associative power, albeit for different reasons (in the case of the first EC1).although for different reasons (in shadowing due to the salience of the stimulus, and in blocking due to the pre-exposure of EC1).

Bibliographical references:

• Pérez, V., Guitérrez, M., Gracía, A., & Gómez, J.(2017). Basic psychological processes: a functional analysis. Madrid (Spain): UNED.
• Domjan, M. (2009), Principles of learning and behavior, Madrid (Spain): Thomson.