Some psychologists, especially behaviorists, avoid studying the “black box” of the mind—internal mental processes that are hard to observe or measure objectively. Instead, they focus only on observable behaviors and how these change in response to environmental stimuli.

Classical conditioning fits this view by showing how behavior can change through associating two stimuli, without needing to consider mental states.

Learning is defined as a relatively lasting change in reaction caused by experience (Pearce, 2008). In classical conditioning, learning happens by forming an association between two stimuli.

Imagine hearing a bell every time food is about to arrive. At first, the bell means nothing, but after several pairings, hearing the bell alone signals mealtime and can trigger salivation. This salivation is a learned response.

Scene 1 Bell (neutral)
Scene 2 Bell + Food (repeatedly)
Scene 3 Bell Ring = Food appearance

This learned response happens because the neutral stimulus (bell) becomes linked to an unconditioned stimulus (food) that naturally causes salivation.

Over time, the bell transforms into a conditioned stimulus, producing a conditioned response similar to the original reflex.

Ivan Pavlov’s dog experiment is a classic example. The Russian psychologist noticed dogs salivated naturally when presented with food. He paired the sound of a bell with food several times. Eventually, dogs began to salivate just by hearing the bell, showing they learned to associate the bell with food. This demonstrated how behavior can be conditioned through stimulus pairing.

Key terms

• Unconditioned Stimulus (UCS): Naturally triggers a response (ie. food)
• Unconditioned Response (UR): Natural reflex to UCS (ie salivation)
• Neutral Stimulus (NS): Initially no response (ie bell sound)

Post experiment

• Conditioned Stimulus (CS): Previously neutral, now triggers response
• Conditioned Response (CR): Learned response to CS (ie salivation at bell)

Another well-known case is Watson and Rayner’s “Little Albert” study. Little Albert, a baby, showed no fear of a white rat initially.

However by pairing the rat with a loud, frightening gong, Albert eventually developed a fear response to the rat alone. This fear generalized to other similar objects, like rabbits and furry hats. This case shows how classical conditioning can apply to emotional responses but also highlights ethical issues such as lack of consent and causing distress to a vulnerable participant.

While classical conditioning on the whole explains how new responses to stimuli develop through association, and how this learning can generalize to similar stimuli, it has limitations, that you can evaluate with IB Psychology concepts.

Concepts

• Sampling Bias: Classical conditioning studies often use animal subjects (ie. dogs), limiting how well findings apply to humans
• Causality: While stimulus-response links suggest causality, complex human behaviors might involve other factors beyond simple associations
• Perspective: Behaviorist perspective ignores internal mental processes (the “black box”), which limits understanding of cognitive or emotional influences
• Measurement: Only observable behavior is measured, which misses internal thoughts or feelings involved in learning
• Change: Learning is seen as a lasting behavior change, but responses can sometimes disappear (extinction) and then reappear later (spontaneous recovery). For example, a dog may stop salivating to a bell after time but start again unexpectedly
• Responsibility: Ethical concerns arise when conditioning is applied in ways that may cause harm or distress (ie. fear conditioning)

Read here for more on Operant Conditioning
See here for more on concepts