We return to the ring with another article that touches on the area of behaviorism (yes, another one). This time, however, we are going to focus on a poorly known and underrated area in the field of learning: classical conditioning.
Classic Conditioning for Beginners
Most of our articles refer to operant conditioning, an area within psychology that is generally associated with the developments of BF Skinner, approximately from the 1940s, which refers to the interaction between behavior and the environment and in particular to how consequences shape behavior (this description is a carnage, but I don’t want to go into too much detail on this topic in this article, you can visit )
Classical conditioning (which is also often called “respondent” or “Pavlovian”), on the other hand, comprises a series of learning principles that arise from the work that Ivan Pavlov carried out at the beginning of the 20th century.
Pavlov’s story is well known to psychology students. Ivan Pavlov was a Russian physiologist who was researching salivary, gastric and pancreatic secretions in dogs, for which he had implemented a device that allowed him to accurately measure the volume of saliva and other secretions emitted by a dog (science is sometimes a disgusting thing, I know). In the course of his research he noticed that the dogs salivated when they saw the white overalls of the people who were going to feed them, that is, they began to salivate. before of receiving the food, what he called a “psychic secretion” (because that secretion did not depend on the food itself but on the anticipation). From then on he changed the focus of his research, and began to investigate under what conditions he could obtain that result.
Pavlov hypothesized that when any stimulus predicts the occurrence of another stimulus that triggers an automatic response, that first stimulus would acquire the ability to trigger that response. Said in a slightly more technical way: an unconditioned stimulus (US) generates an unconditioned response (IR). Having food in the mouth (EI) naturally triggers salivation (RI); If a neutral stimulus (e.g., in the case of Pavlov’s dogs, seeing people providing food) repeatedly predicts the unconditioned stimulus, that stimulus will begin to trigger the unconditioned response. That stimulus will be called the conditioned stimulus (CS), and the response that that stimulus triggers will then be called the conditioned response (CR). Pavlov then experimented associating different sounds and visual stimuli with food. For example, he would play a metronome before feeding a dog; After repeating this several times, it was enough for the dog to listen to the metronome for it to start salivating (note for pedants: despite popular legend, Pavlov never used a bell, because such a stimulus would be too imprecise and difficult to control1). The thing would go like this:
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- Presentation of Unconditioned Stimulus (US – food)———Triggers Unconditioned Response (IR – salivation)
- Presentation of a neutral stimulus (metronome) before presenting the US (food)—Triggers unconditioned salivation response. This pairing is repeated several times.
- The Conditioned Stimulus (CS – metronome) now generates a conditioned Response (CR – Salivation)
Pavlov thus established one of the most important moments in the history of psychology. He had discovered a principle of learning that was applicable to both animals and humans, allowing both to predict and establish new responses. Although Pavlov was not a behaviorist, the principles he discovered inspired the first generations of behaviorism, and were the basis for an entire field of scientific psychology. During the 20th century, thousands of psychologists and researchers used these principles, making them more complex and refining them, and perhaps it is precisely the success that Pavlov had (or rather, his research), which made him remain a bit in the background in psychology. Today, classical conditioning is often taught as if it were a footnote in psychology courses, a mere historical anecdote of an obsolete approach.
Now, do you remember Schwarzenegger in Terminator? Well, “I’ll be back” could very well have been said by Pavlov (and yes, I have given myself the pleasure of giving this article a Hollywood title).
Today a plethora of research uses the principles of classical conditioning in areas that are of extraordinary interest in psychology, and I don’t mean research that “more or less has something to do with classical conditioning,” but rather that is explicitly based on those principles. If you’ll join me, let’s look at some of those areas.
We are going to skip the most well-known applications of classical conditioning such as phobias and basic learning, since you can read about them in any textbook. Let’s take a look, instead, at the most underground, most unknown applications and developments of classical conditioning. In the classic example of Pavlov’s dog, what is conditioned is the secretion of a gland (salivary, to be more precise). Now, what other responses can be influenced by classical conditioning mechanisms? We are going to examine two areas: drug response and immune response.
Drug tolerance and overdose
This is a fascinating line of research.
Suppose we administer an injection of adrenaline to a person, preceded by, say, an audible tone. As you may know, adrenaline has the effect of increasing heart rate and blood sugar. In this example, adrenaline would be an unconditioned stimulus (US), the audible tone would be the conditioned stimulus (CS), and the increase in blood pressure and decrease in blood sugar would be the unconditioned response (IR). Now, if we repeat this procedure several times, what do you think would happen when presenting the audible tone alone?
Intuitively we would probably say that the audible tone, like the metronome in the case of Pavlov’s dog, would generate an adrenaline-like increase in heart rate.
Mistake (I love saying that). What happens in these cases is that when the tone, heart rate and blood sugar level present they descend2. It is what is called a conditioned response contradirectional (because it goes in the opposite direction to IR). So to speak, the body “compensates” for the effect of the adrenaline that is going to be administered and – this is the crucial part – this compensation makes the effect of the adrenaline that is administered minor. These contradirectional responses have been observed in the administration of amphetamines, atropine, chlorpromazine, glucose, histamine, lithium, morphine, naloxone, among others3.
The interesting part is that this explains drug tolerance and overdoses. When a drug is administered repeatedly in the same context (the same room, for example), that context or stimulus becomes a CS that triggers a compensatory CR, and thus decreases the effect of that drug. Now, when that same drug with the same dose is administered in a new context, that compensatory response does not occur; There is nothing that “warns” the body that it is going to receive a dose, which is why the effect of the drug, now unchecked, multiplies and produces a overdose.
This compensatory response (and its absence) can have dramatic consequences. Schneider4 tells the following anecdote:
“A man may have killed his father unintentionally. His father, who suffered from pancreatic cancer, was receiving care at his home in a poorly lit bedroom. He was in a lot of pain and received four morphine injections a day. On the day of his death, the son found that his father had moved into the living room, which was very bright, and since it was time for his injection and his father was in pain, the son administered his usual dose of morphine. in that place. The father’s reaction was exceptional, and a doctor immediately diagnosed an overdose of morphine, but nothing could be done.
Of course, it is impossible to know for sure whether there were classical conditioning mechanisms in this story, but it is quite likely that there were. Numerous research reports this effect on the development of drug tolerance and overdose. In a study, Siegel and collaborators found that a mere change of location was enough to double the occurrence of overdose5.
The same mechanism explains the impulses (craving), for drug consumption. Allow me a detour to explain this. Surely you are familiar with what happens to us when we see food in a shop window or when we smell the roast that our unfortunate neighbor is cooking. In those cases, we not only drool like dogs, but often we actually start to feel hungry. In part this is explained by a contradirectional response: the body, faced with the urge to see food, begins to increase insulin production, which generates a drop in blood sugar and thus we begin to feel hungry (in the next section we will talk about More of this). Similarly, exposure to stimuli linked to drug use can trigger a compensatory response that increases the desire to use.
Some clinical indications are derived from this2. Firstly, it follows that it is relatively easy to be abstinent if one does not confront stimuli linked to consumption; Secondly, relapses are more likely as soon as a person in recovery is exposed to stimuli associated with consumption (for example, when a person is discharged from an addiction clinic and returns to live in environments previously associated with consumption). Finally, relapse prevention is facilitated if the link between stimuli and consumption is weakened. This is what is called “signal exposure” (cue exposure therapy), and basically consists of exposing yourself to the stimuli that trigger consumption while blocking the response to consume. The evidence for this type of intervention is still in its early stages but appears to be promising6. (To read a little more about the effect of the environment on drug administration you can read)
Immune response and medicine
It seems like something taken from the worst pages of bad psychology books (I’m not going to name any so as not to offend people), but it seems that the body’s immune response is also susceptible to being influenced by classical conditioning.
In a now classic study, Ader and Cohen (1975)7 accidentally discovered that they could condition an immunosuppression response. They observed that if in a classical conditioning procedure they associated…