IB Psychology SL Topic 4 — Thinking & Learning Paper 1 & 2 Behaviourist approach ~9 min read

Operant Conditioning: Learning by Consequence

Classical conditioning is about what happens before a behaviour. Operant conditioning is about what happens after. Do something, see what it gets you, and adjust. Simple — until you notice how many people repeat behaviour that clearly costs them.

📚 What you need to know

Four boxes, two questions

Students lose easy marks here because they read ‘negative’ as ‘bad’. It does not mean that. Ask two questions instead: is the behaviour going up or down, and is something being added or taken away? The answers give you the term.

The four consequences, sorted by two questions Positive means added, negative means removed — not good or bad Something is added Something removed Behaviour goes up Behaviour goes down Positive reinforcement You get something good Homework earns praise You do it again Negative reinforcement Something bad stops Homework avoids detention You do it again Positive punishment You get something bad Being told off You do it less Negative punishment Something good is taken Losing your privileges You do it less Both top boxes increase behaviour, so both are reinforcement Negative reinforcement is a reward, not a punishment. This is the big trap.
A reinforcer is the consequence, not the behaviour. Praise from a teacher is a positive reinforcer; a detention is a positive punishment.
Sometimes a behaviour is repeated not because it brings something good but because it stops something annoying. Choosing the salad so your friend stops commenting on your diet is negative reinforcement, not healthy eating.

Key study: Skinner (1953)

Skinner argued that learning is active. Organisms operate on their environment and get shaped by what their actions produce. He identified three types of consequence: neutral operants, which change nothing; reinforcers, which make a behaviour more likely; and punishers, which make it less likely.

Condition in the Skinner boxWhat happened
Positive reinforcementA hungry rat exploring the box accidentally pressed a lever and received a food pellet. Adding food after the press increased lever-pressing, and rats soon pressed the lever immediately on being placed in the box.
Negative reinforcement (escape)A mild electric current ran through the grid floor. Pressing the lever turned it off. Removing the unpleasant stimulus reinforced the behaviour, and rats learned to press quickly to escape.
Negative reinforcement (avoidance)A light signalled that a shock was coming — a discriminative stimulus. Rats learned to press the lever as soon as the light appeared, avoiding the shock entirely.
What it showedBoth adding a pleasant stimulus and removing an unpleasant one strengthen behaviour. Reinforcement is about the effect on the behaviour, not about whether the consequence feels nice.

Evaluating operant conditioning

What is strong about it

What is weaker about it

Link to concepts

EXAM PRACTICE

Discuss operant conditioning as an explanation of learning. [22]

Step 1: define it precisely Learning through consequences. Reinforcement increases behaviour; punishment decreases it. Positive means added, negative means removed. Step 2: the study Skinner (1953), the Skinner box, with rats. Step 3: the conditions Food pellet for lever-pressing increased the behaviour. Turning off a shock did the same. With a warning light, rats pressed to avoid the shock altogether. Step 4: application Explains how phobias are maintained: avoidance brings relief, so avoidance is reinforced. Step 5: evaluate Reliable and falsifiable, but reductionist, cannot explain self-damaging behaviour, ethically questionable, and learned helplessness explains some cases better. Definition + study + conditions + application + evaluation The self-harm and smoking examples are the sharpest limitation. They are behaviours OC says should not exist.

💡 Exam tip

⚠ Common mix-up

Up next: The Dual Process Model of Thinking — back to cognition, and the two very different gears the mind switches between.

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