Classical Conditioning

What is Classical Conditioning? 

Classical conditioning is a form of associative learning between an automatic stimulus and a specific stimulus.
*Classical conditioning would be referred to as CC in the remaining text.*

How does Classical Conditioning work?

Before we start, there are a few terms to know about:

Unconditioned Stimulus (UCS) - Any stimulus that will always and naturally elicit a response.
Unconditioned Response (UCR) - Any response that always and naturally occurs upon the presentation of the UCS.
Neutral Stimulus (NS) - Any stimulus that does not naturally elicit a response associated with the UCR.
Conditioned Stimulus (CS) - Any stimulus that will, after association with a UCS, cause a conditioned response (CR) when present to a subject by itself.
Conditioned Response (CR) - Any response that occurs upon the presentation of CS.

So how do CC works?

It involves presenting a neutral stimulus before an unconditioned stimulus (that produces an automatic, unconditioned response) frequently in order to use the neutral stimulus as a predictor of the unconditioned response.

CC occurs when the association between the neutral stimulus and the unconditioned response are learned, so the neutral stimulus and the unconditioned response would then be conditioned stimulus and conditioned response.

Let's look at the famous experiments to get a better idea of classical conditioning:

Pavlov's dog 🐶

From Pavlov’s 🐶 experiment, CC demonstrated how a 🐶 learns to salivate with the presence of a bell, and without the presence of food.

As we know, it is an innate and natural response for dogs to salivate (UCR) after smelling the food (UCS). However, 🐶 will not salivate when they hear a bell tone (NS).

In the experiment, Pavlov presented the 🔔 (NS) and the food (UCS) together (bell tone first, food later) and it elicited a salivation response due to the presence of food (UCR).

After several times of conditioning (by presenting the bell tone & food), the dog learns that when the bell sound is presented, the food will also be presented. Therefore, the dog would salivate (UCR -> CR) the next time upon hearing a bell tone (NS -> CS), even with the food being absent.

The Little Albert Experiment

The Little Albert experiment is conducted by Watson and Rayner in 1920, where they aim to examine (1) whether CC could be applied in humans, and (2) whether fear is an innate or conditioned response. They recruited the 11-months-old Little Albert as their experiment subject.

Before the experiment, Little Albert was first exposed to a series of objects including a white rat, rabbit, monkey, white coat and etc. The experimenters determined that Little Albert show no fear towards any of the stimuli. However, when the experimenters struck a steel bar with a hammer, Little Albert showed a fear response (crying).

During the experiment, Little Albert would be first presented with a white rat 🐁 (NS), and once he touched the rat, the experimenters would strike the steel bar immediately behind Little Albert (see picture below) that produces a loud noise (UCS) and causes Little Albert to cry (UCR).

After repeating it a few times, Little Albert has learned the association between the white rat and the loud sound caused by striking the steel bar. In the end, upon seeing the white rat 🐁 (NS -> CR), he would produce a fear response (cry immediately) (UCR -> CR).

becomes

However, this is not the end of this experiment. Little Albert's fear of the white rat was generalized to anything that has the characteristics of the white rat -- white and/or fluffy. In other words, he would produce a similar conditioned response (fear/crying) when he sees a white and/or fluffy thing (eg. white coat, a white rabbit, etc).

Before Watson and Rayner attempted to 'cure' Little Albert, Little Albert's mother and himself had moved away together with his previously conditioned fear response towards white and/or fluffy objects, and disappeared from everyone. Their whereabouts were unknown since then.
Although this 💢unethical💢 experiment had successfully indicated the application of CC in humans and the learning of fear, it has caused significant damage to Little Albert.

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In short,
Classical conditioning demonstrated how learning new associations would help to shape new behaviours and responses. These experiments suggested that through associating two different (even unrelated) stimuli, a new learned response could be created.

References/Resources:

1. What is classical conditioning?
2. What Happened to Little Albert? check this link to find out what happened and what is the true identity of Little Albert!
3. McLeod, S. A. (2018, October 08). Pavlov's dogs. 
4. Watson, J. B., & Rayner, R. (1920). Conditioned emotional reactions. Journal of experimental psychology, 3(1), 1.