AP Psychology · Lesson 2

Conditioning and social learning

Know Know it

Classical conditioning, first studied by Pavlov, links two stimuli. An unconditioned stimulus (UCS), such as food, triggers an unlearned unconditioned response (UCR), such as drooling. A neutral stimulus paired with the UCS becomes a conditioned stimulus (CS) that triggers a conditioned response (CR) on its own. Building this link is acquisition.

If the CS keeps appearing without the UCS, the CR fades: extinction. After a rest, it may briefly return: spontaneous recovery. Responding to stimuli similar to the CS is generalization, and telling them apart is discrimination. A taste aversion can form after a single pairing of food and illness, even hours apart, which shows that some links are easier to learn than others (biological preparedness).

Operant conditioning links a behavior to its consequence. Thorndike's law of effect says behaviors followed by good outcomes become more likely. Skinner studied how reinforcement strengthens behavior and punishment weakens it. Positive means something is added, and negative means something is taken away.

Shaping reinforces closer and closer steps toward a target behavior. Primary reinforcers meet basic needs, like food, and secondary reinforcers, like money, gain value by association. Animals may slip back toward instinctive behaviors during training, which is instinctive drift.

Schedules of reinforcement matter. Continuous reinforcement builds a behavior fast but extinguishes fast. Partial schedules are fixed or variable, and based on a ratio (number of responses) or an interval (time). Variable-ratio schedules produce the highest steady rates and the most resistance to extinction.

Social and cognitive learning need no direct reward. In observational learning, Bandura showed that children imitate a model, and vicarious reinforcement (seeing a model rewarded) makes imitation more likely. Tolman found latent learning, learning that stays hidden until it is useful, and cognitive maps. Köhler described insight learning, a sudden solution. Learned helplessness develops when repeated experience teaches that actions do not matter.

Reinforcement and punishment in operant conditioning
Something is addedSomething is removed
Behavior increasesPositive reinforcement: praise for finishing homeworkNegative reinforcement: an alarm stops when you get up
Behavior decreasesPositive punishment: a fine for speedingNegative punishment: losing phone time for lying

Trap Negative reinforcement is not punishment

Reinforcement always makes a behavior more likely, and punishment makes it less likely. Negative reinforcement removes something unpleasant, so the behavior goes up. Ask first whether the behavior rises or falls, then whether something was added or removed.

Worked example Easy

Every time Milo's owner opens a can of dog food with an electric can opener, Milo gets fed. After a few weeks, Milo drools as soon as he hears the can opener, even before any food appears.

In this example, what is the sound of the can opener now?

  1. Unconditioned stimulus
  2. Conditioned stimulusAnswer
  3. Unconditioned response
  4. Conditioned response

How to solve it

  1. Food causes drooling without learning, so food is the UCS.
  2. The sound became meaningful only by being paired with food.
  3. A learned trigger is a conditioned stimulus.

Why each choice is right or wrong

  • A. Incorrect. The unconditioned stimulus is the food, which causes drooling without any learning.
  • B. Correct. The sound was neutral at first, but after being paired with food it now triggers drooling by itself.
  • C. Incorrect. A response is something Milo does, and the can opener's sound is a stimulus, not a response.
  • D. Incorrect. The conditioned response is Milo's drooling to the sound, not the sound itself.

Explain Explain it

Task verbs: identify, explain

For operant questions, ask two things in order: does the behavior go up or down, and was something added or removed? For schedules, ask whether rewards depend on responses or on time, and whether they are predictable.

Worked example Hard

Ana's parents tell her that in any week she turns in all her homework, she will not have to wash the dishes on Saturday. Over the next two months, Ana turns in all her homework more often.

Which operant process explains the change in Ana's behavior?

  1. Positive punishment
  2. Negative punishment
  3. Positive reinforcement
  4. Negative reinforcementAnswer

How to solve it

  1. Her homework completion goes up, so this is reinforcement.
  2. The dishes, an unpleasant chore, are removed.
  3. Removing something to increase a behavior is negative reinforcement.

Why each choice is right or wrong

  • A. Incorrect. Positive punishment adds something unpleasant to reduce a behavior, but Ana's homework rises and nothing is added.
  • B. Incorrect. Negative punishment removes something pleasant to reduce a behavior, yet her homework completion goes up.
  • C. Incorrect. Positive reinforcement adds something pleasant, but here a disliked chore is taken away.
  • D. Correct. Removing an unpleasant chore after the behavior makes the behavior more likely, which is negative reinforcement.

Explain Your turn

A trainer gives a puppy a treat after an unpredictable number of sits: sometimes after 2 sits, sometimes after 6. Name the reinforcement schedule, and use what the puppy experienced during training to explain why it keeps sitting for a long time after the treats stop.

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Compare with a model answer

A full answer does this

  • Names the variable-ratio schedule
  • Explains the long persistence by the unrewarded sits the puppy met during training

Model answer

This is a variable-ratio schedule, because a treat came after an unpredictable number of sits. During training the puppy often sat several times in a row with no treat, so a run of unrewarded sits is nothing new to it. When the treats stop, the puppy cannot tell the change from an ordinary dry spell, so it keeps sitting much longer than it would after a treat for every sit.

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