Excitatory and inhibitory conditioning: what do they consist of?

In the study of animal and human behavior and learning, classical conditioning has been a reference. In this, the response that an organism automatically displays to a stimulus is transferred to another through an association between both (Sarason and Sarason, 2006).

Within classical conditioning we can find several types of conditioning, among which the following stand out: excitatory and inhibitory conditioning. Before delving into these two, we will briefly review some central concepts that will allow us to understand them better:

Unconditioned stimulus (US): is any stimulus with sufficient intensity to produce a response. It does not require experience on the part of the organism to produce the response.Unconditioned response (IR): is the response triggered by the unconditioned stimulus.Neutral stimulus (EN): stimulus that has no effect on behavior or that does not produce a response.Conditioned stimulus (CS): arises from the repeated association between the EI and the EN. This stimulus acquires the properties of the US to produce a response similar to the IR, known as a conditioned response.Conditioned response (CR): is the response caused by the EC when they have associated.

Excitatory conditioning

In behaviorism, Excitatory conditioning occurs when a conditioned stimulus produces a conditioned response, similar to the unconditioned response caused by the unconditioned stimulus. In other words, excitatory conditioning activates conditioned responses in an organism. This form of conditioning is the most common, and also the easiest to carry out.

However, How is it possible that a conditioned stimulus can provoke a conditioned response similar to the response provoked by an US? This is due to the association between stimuli. At first, the CS appears as a product of the association between a neutral stimulus and an unconditioned one, in which the NE acquires property of the US, thus becoming a CS.

Examples of excitatory conditioning include fear conditioning and taste aversion.

For example, when we feel bad after eating or drinking something – it doesn’t have to be bad, it may be that our body tolerates it with difficulty or that we have even binged – we no longer want to try that substance again and Even when thinking about it, we can feel the discomfort it caused us.

Another classic example is Pavlov’s dog experiment, which secreted saliva just by hearing the sound of a bell that had been associated with food (EI). At first, the bell alone was not capable of generating salivation in the dogs, but when it was presented together with food, which did generate salivation, the dogs began to salivate just by listening to the bell, since they had learned (they had learned conditioned) that food came with it.

Thus, in excitatory conditioning, the presentation of a conditioned stimulus activates the behavioral and neuronal response related to the unconditioned stimulus, without the actual presentation of the latter. The conditioned responses that can be observed in an organism are based on processes related to unconditioned stimuli.

inhibitory conditioning

In studies on excitatory conditioning, a CS predicts the occurrence of an US. But what would happen if the EC predicted the absence of the IS? We could come to believe that if a CS is not followed by an US, then it is a neutral stimulus that has no motivational or activating value for the subject. But we would be wrong. In fact, The CS that predicts the absence of the US is not a neutral stimulus, it is an inhibitory conditioned stimulus (CS-).

Inhibitory conditioning is that in which the CS is not followed by the US, Therefore, it would not provoke the response that it would normally produce in the presence of IS. If it produces a response, it would be opposite to that of excitatory conditioning.

Inhibitory conditioning is basically contrast learning (Sánchez et al., 2008). Let’s see what this means.

One of the main procedures to generate inhibitory conditioning is the differential procedure. During the acquisition phase of a behavior, excitatory trials are used in conjunction with inhibitory trials that are presented randomly throughout the experimental session.

In excitatory tests, the CS is systematically followed by the US, while in inhibitory tests, it is not.

Another example would be that of a puppy that fears the attack of a predator as a danger signal (excitatory conditioned stimulus), but in the presence of its mother (inhibitory conditioned stimulus) it does not fear the threat.

At the traffic light, the inhibitory conditioned stimulus would be green, which signals the absence of danger.

Comparison between excitatory and inhibitory conditioning

Although both types of conditioning are different, we can observe a common point: the relationship. In the case of excitatory conditioning, the relationship between CS and US is positive – that is, there is an association -, while in the case of inhibitory conditioning the relationship is negative, that is, there is no association.

The non-association between stimuli is also a way of relating. In human and animal life, the relationship is an inherent characteristic, and if we talk about classical conditioning, even more so. Both forms of conditioning provoke a response in organisms that allow them to adapt and respond to the environment.

Starting from this factor that they have in common, we can observe the main difference between the two: one provokes responses, activates them (excitatory conditioning), while the other inhibits them (inhibitory conditioning). Although they are opposite poles in this sense, both allow the behaviors of organisms to be balanced for better adaptation.

To end, Excitatory and inhibitory conditioning are a continuum along the lines of classical conditioning. Each one has a specific function (activate or inhibit) that allows the individual or organism to acquire and consolidate certain behavioral patterns.

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