Schedules of reinforcement and Skinner (1948)

Continuous and partial reinforcement

• Continuous reinforcement: every correct response is reinforced. Learning is quick, but the behaviour extinguishes quickly when reinforcement stops (e.g. a vending machine: if it stops working, you stop using it).
• Partial reinforcement: only some responses are reinforced. Behaviour is more resistant to extinction (the partial reinforcement extinction effect).

The four partial schedules

Ratio schedules depend on the number of responses; interval schedules depend on time. Variable schedules give steadier responding than fixed ones.

Skinner (1948): 'Superstition' in the pigeon

• Eight hungry pigeons were placed in a cage where a food hopper opened at regular intervals (for example every 15 seconds) for 5 seconds, regardless of what the bird was doing.
• Six of the eight developed clear, repeated behaviours: turning anticlockwise, thrusting the head into a corner, a 'tossing' head movement, swinging the head and body like a pendulum.
• Whatever the bird happened to be doing when food arrived was accidentally reinforced, so it was repeated, making it more likely to be reinforced again.
• In extinction one response continued for more than 10,000 responses before nearly stopping.

Conclusion: the bird behaves as if its behaviour caused the food. Skinner compared this to human superstitions, such as rituals for changing one's luck at cards, kept going by occasional accidental pairings with good outcomes.

Evaluation of Skinner (1948)

• Strengths: controlled laboratory conditions; behaviour objectively recorded; shows reinforcement can shape behaviour without any real connection.
• Weaknesses: pigeons may not generalise to human superstition, which involves beliefs and culture; small sample (8 birds); food deprivation raises ethical issues for animals; other researchers have offered different explanations of the birds' behaviour.

Worked example

A gambler keeps playing a slot machine even after a long losing run. Use schedules of reinforcement to explain why.

1. Slot machines pay out on a variable ratio schedule.
2. The gambler cannot predict which play will be rewarded, so the next one might be.
3. Variable ratio schedules produce high, steady responding that is very resistant to extinction.

Answer: Variable ratio reinforcement makes the behaviour persistent and hard to extinguish.

Check yourself

1. Which schedule produces behaviour most resistant to extinction?
   • Continuous reinforcement
   • Fixed interval
   • Variable ratio
   • Fixed ratio
   Show answer

   Variable ratio. VR gives very high, steady responding that lasts.

2. Students revise little until just before a test every Friday. Which schedule does this show?
   • Fixed interval
   • Variable ratio
   • Variable interval
   • Continuous
   Show answer

   Fixed interval. Responding speeds up as the fixed time approaches.

3. A factory worker is paid for every 20 items made. This is
   • variable ratio
   • fixed interval
   • fixed ratio
   • variable interval
   Show answer

   fixed ratio. A set number of responses earns the reward.

4. What is the main drawback of continuous reinforcement?
   • Learning is very slow
   • The behaviour extinguishes quickly when reinforcement stops
   • It can only be used with humans
   • It always produces superstition
   Show answer

   The behaviour extinguishes quickly when reinforcement stops. Fast learning but fast extinction.

5. How many pigeons in Skinner (1948) developed clearly defined 'superstitious' responses?
   Show answer

   6 pigeons. Six of the eight pigeons.

6. What percentage of Skinner's pigeons developed clear superstitious responses?
   Show answer

   75 %. 6 / 8 x 100 = 75%.

7. Explain how Skinner's pigeons developed 'superstitious' behaviour.
   Show answer

   Food arrived at regular intervals regardless of behaviour, so whatever the pigeon happened to be doing at that moment was accidentally reinforced, making it more likely to repeat that action, which was then reinforced again.. Accidental reinforcement.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification, Issue 5 (February 2021)
• Pearson IAL Psychology component guide: WPS02 (Issue 2, November 2024)
• Simply Psychology: Schedules of reinforcement
• Skinner (1948), 'Superstition' in the pigeon, Journal of Experimental Psychology 38 (B. F. Skinner Foundation copy)

Last updated 8 November 2026. Spotted a mistake? Tell us.