Overshadowing: What It Is And How It Is Used In Classical Conditioning
In psychology, a good part of the behavioral phenomena described by this science have to do with learning.
Overshadowing is one of the concepts that refers to how we learn through classical conditioning, and in this article we will see what it consists of. Let’s start with the fundamentals.
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 topic 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 from operant or instrumental conditioning).
CC consists of 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 provoke a response, comes to provoke one thanks to the associative connection of this stimulus with the stimulus that normally provokes said response.
The CC allows teaching children to perform desired behaviors associating stimuli with other unconditioned stimuli that already generate the target behavior in the child (for example, associating a bell (CS) with the beginning of recess (EI), so that children prepare to go out to the playground when they hear the bell.
This type of learning will allow us to establish routines that help children anticipate the behaviors they have to perform. This learning is of vital importance when working with children who have special educational needs, since these routines prevent them from becoming disoriented and the appearance of anxiety.
Overshadowing: 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 (salience) followed by an unconditioned stimulus (US).
This sequence implies a conditioned response (CR) of greater intensity to the most salient stimulus. Thus, if A is more salient than B, it will be conditioned more quickly than B, and also will make it difficult to condition B.
In this way, the more the CS stands out from the rest of the stimuli present during the acquisition (which can be one or several), the better the conditioning is.
Shadowing experiments
A typical overshadowing experiment would include two groups of subjects and two stimulus elements, one of high intensity (A) and one of low intensity (b).
For the overshadowing group, the two stimuli are presented together (Ab) as a compound cue paired with reinforcement during conditioning. For the control group, only the low intensity stimulus (b) is presented during conditioning.
Tests are carried out for each group presenting only the weakest element of the stimulus (b). These tests show a lower number of ab responses (RC’s) in the overshadowing group than in the control group.
Thus, it is observed how the presence of A alters the control of behavior by the weaker stimulus, b. In more precise terms, we will say that A has reduced the power of association with the reinforcer from B.
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 the salience and only the intensity is varied.
Thus, logically, of two environmental elements (neutral stimuli) paired with EI, We will pay more attention to the most outstanding one, to the one that catches 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 prominent than a sign on a pole, and therefore, less effective. In this case, the salience will also have to do with the location of the sign and our position when driving (the sign on the pole will be more visible to us, more striking).
Furthermore, as an addition we know that the sign on a post has preference over a graffiti in the dream, in the case of finding a contradiction between the two.
Differences between overshadowing and blocking
We should not confuse overshadowing with a similar but not identical phenomenon, the blocking effect.
This also consists of a phenomenon of classical conditioning, and it is that a conditioned stimulus (CS1) is paired with an unconditioned stimulus (US) in a first phase, and in a second phase both CS1 and a new conditioned stimulus (CS2) are paired next to the US; All of this causes the learning of EC2 to be hindered.
That is, the conditioning of a first CS (CS1) makes it difficult to learn a second CS (CS2) later.
Thus, we see that both in the overshadowing and in the blocking, one stimulus causes another to lose associative power although for different causes (in the overshadowing due to the salience of the stimulus, and in the blockade due to the pre-exposure of EC1).
