Introducing Classical Conditioning

Picture this: you're craving a delicious burger and decide to try Burger King for the first time on a friend's recommendation. Intrigued, you order their signature Whopper online. As soon as you open the box, your salivary glands kick in and you drool over the burger (who wouldn't?). It’s so good that it becomes your default burger of choice. But then, something curious happens. Simply, the Burger King logo gets your mouth watering. It’s like your brain has been conditioned to react automatically. This would be Classical Conditioning— a.k.a. Pavlovian Conditioning or Respondent Conditioning, in action.

Learning is seldom an active endeavour; unconscious learning, as the name suggests, often occurs outside your conscious awareness. One example of unconscious learning is Classical Conditioning, as conceptualized by Ivan Pavlov. He defined it as a form of automatic, associative learning where a previously neutral stimulus, following repeated pairings with an unconditioned stimulus, transforms into a conditioned stimulus and elicits a conditioned response. Now, hold on, what do any of these terms even mean? Let's explore this concept further, using Burger King as our illustrative example. 

1. Unconditioned Stimulus (US): A stimulus that automatically elicits a response without prior learning (the Whopper).

2. Neutral Stimulus (NS): A stimulus that does not trigger a particular response (Burger King logo).

3. Conditioned Stimulus (CS): A previously neutral stimulus (NS) which, after repeated pairings with a UCS, triggers a particular response.

4. Unconditioned Response (UR): A response naturally elicited by a UCS (salivating in response to the Whopper).

5. Conditioned Response (CR): A learned response triggered by the CS (salivating in response to Burger King).

Let's apply this to our narrative. Initially, Burger King did not trigger salivation and was a neutral stimulus (NS). Each time, without fail, the Whopper (US) would trigger salivation (UR). Gradually, you began associating the Whopper and Burger King together, so much so that the mere thought of Burger King (now CS) would trigger salivation (CR). 

But wait, there’s more! Unconditioned stimuli (US) can be classified into two categories: appetitive and aversive. Appetitive US is desirable and sought out, like the Whopper. Because you enjoy the Whopper, it acts as an appetitive US, and eventually, Burger King itself becomes a conditioned stimulus (CS) associated with that pleasure. This process is known as Appetitive Conditioning.

On the other hand, if the unconditioned stimulus were something unpleasant—for instance, a foul smell or an extreme temperature—it would be an aversive US. When conditioning involves an aversive US, it’s called Aversive Conditioning. Imagine you are enjoying a Whopper with pickles, unaware you are allergic to pickles. Yikes. Let's hope the doctor can squirt the epinephrine in your mouth like a squirt gun because you are afraid of needles!

In this case, the allergic reaction to eating pickles would be an unconditioned response, thereby making the consumption of pickles an aversive unconditioned stimulus. Similarly, the pain from the needle insertion is the aversive unconditioned stimulus, and the flinching caused by the pain would be the unconditioned response.

This Burger King saga emphasizes the subtleties of unconscious learning, wherein the interaction between stimuli and responses thoroughly demonstrates Classical Conditioning. You did not consciously learn to salivate at the thought of Burger King; it merely happened through the power of association and Classical Conditioning!

References: -

Rehman I, Mahabadi N, Sanvictores T, Rehman CI. Classical Conditioning. In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2023. PMID: 29262194.

Pavlov, I. P. (1927). Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex. Oxford University Press.

Domjan, M. P. (2018). Principles of learning and behavior. Cengage Learning.