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Learning

Chapter 6

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Definition: Learning

• “Learning” is defined in psychology as ‘a relatively permanent behavior change as a result of experience.

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Learning

How Do We Learn?

Classical Conditioning Pavlov’s Experiments

Pavlov’s Legacy

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Learning

Operant Conditioning Skinner’s Experiments

Skinner’s Legacy

Contrasting Classical & Operant Conditioning

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Learning

Biology, Cognition, and Leering Biological Constraints on Conditioning

Cognitive Processes and Classical Conditioning

Cognitive Processes and Operant Conditioning

Learning by Observation

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How Do We Learn?

• By linking events that occur close together, humans and other animals exhibit associative learning. – This process of learning associations is called

conditioning.

• There is also cognitive learning, – the acquisition of mental information by

observing events, watching others, or through language.

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Classical Conditioning

• A stimulus is an event or situation that evokes a response.

• In classical conditioning, we learn to associate two stimuli; the unconditioned response to one stimulus becomes the conditioned response to the other.

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Classical Conditioning: Pavlov’s Classic Experiment

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Classical Conditioning• The neutral stimulus (NS) elicits no response

before conditioning.

• The unconditioned stimulus (US) is a stimulus which triggers a reflex (automatic response, UR) without conditioning.

• The conditioned stimulus (CS) is an originally neutral stimulus that, after association with a US, comes to trigger a CR.

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Classical Conditioning• The unconditioned response (UR) is an

unlearned, natural response to a US

• The conditioned response (CR) is a learned response to a previously neutral stimulus (CS). It is the same action as the unconditioned response, except that it is now triggered by the formerly neutral stimulus (now CS).

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Conditioning Processes

• Pavlov and his associates identified five major conditioning processes: – Acquisition– Extinction– Spontaneous recovery– Generalization– Discrimination

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Acquisition

• Acquisition is the first stage in classical conditioning – where a NS is linked with a US that the NS begins triggering the CS

Why are our bodies set up to be conditioned?

Classical conditioning helps us prepare for good and bad events.

This is why the neutral stimulus must happen first for conditioning to occur; it is the event we use as a warning for the bad, a clue that helps us find the good!

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Extinction and Spontaneous Recovery

• If, following acquisition, the CS occurs repeatedly without the US, it can lead to extinction, the weakening of the CR.

• After a delay (a few hours more), however, the CS may elicit a spontaneous recovery of a (weakened) CR

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Generalization

• Generalization: after conditioning, an organism may respond similarly to stimuli that resemble the CS

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Generalization

• Child abuse can lead to general hypersensitivity to the faces of any angry person, not just their abusers.

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Discrimination

• Organisms also learn to discriminate, or distinguish, between a CS and other stimuli.

• Consider your responses to a guard dog and a guide dog: would they both make your heart pound with fear?”

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Pavlov’s Legacy

1. Many responses can be classically conditioned in many other creatures– I remember the ‘worm runners’ journal—had

articles about conditioning worms.

2. Learning can be studied objectively

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Can Pavlov’s work help us understand emotions?

• Little Albert– John B. Watson and Rosalie Rayner (1920) worked

with 11-month old boy– Little Albert feared loud noises but not white rats– Watson presented him with white rat

• just as he reached out to touch it, Watson made a very loud noise just behind Little Albert’s head

• After 7 repetitions, Little Albert burst into tears at sight of rat– 5 days later, he had generalized this fear to a rabbit, a dog,

and a sealskin coat

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Operant Conditioning

• Classical conditioning involves an automatic response to a stimulus

• Operant Conditioning involves associating a behavior with consequences.

• Consequences: – Reinforcers following a behavior make that behavior

more likely to happen again, and – Punishments following a behavior make it less likely

to recur.

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Operant Conditioning

(a) Response: (b) Consequence: (c) Behavior strengthened Balancing a ball Receiving Food

If a seal is an aquatic exhibition balances a a ball on its nose, it receives a food reward which increase the likelihood that he will balance the ball again.

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B. F. Skinner’s Experiments

• Skinner designed an operant chamber (a Skinner Box) – a box with a recording device to track how often an animal presses a bar to obtain reinforcement – any event or other consequence that strengthens the behavior it follows.

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Reinforcement for the Individual

• What is reinforcing to one individual?• Can vary by situation – a cold drink is

reinforcing if you are hot, but not if you are cold

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Shaping Behavior

• Shaping: gradually guiding actions closer and closer toward a desired behavior, using reinforcement.

• Using successive approximations, one rewards responses that are ever-closer to the desired behavior.

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Types of Reinforcers

• Positive reinforcement: anything that strengthens a response

• Negative reinforcement: anything that, when removed, strengthens response– Negative reinforcement is NOT a punishment

• If I say, you are not going out tonight because you didn’t clean your room—that is punishment

• If I say, you can go out when you clean your room—that is negative reinforcement

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Types of Reinforcers

• A primary reinforcer is innately reinforcing (e.g., giving food when hungry, or alleviating a headache).

• A conditioned (secondary) reinforcer gains its reinforcing power through links with a primary reinforcer—money is a secondary reinforcer.

• Most organisms require immediate reinforcement, but humans can also use delayed reinforcement

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Reinforcement Schedules

• Continuous reinforcement – reinforcing desired response every time it occurs– Learning occurs rapidly, but so does extinction

• Partial (intermittent) reinforcement – reinforcing a response only part of the time– Learning is slower but increased resistance to

extinction

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Partial Reinforcement Schedules for Operant Conditioning

• Fixed-ratio schedule – reinforces response only after fixed number of responses

• Variable-ratio schedule – reinforces response after an unpredictable number of responses– Produces high rates of responding

• Fixed-interval schedule – reinforces response only after a specified time has elapsed– Produces choppy start-stop pattern

• Variable-interval schedule – reinforces response at variable time intervals– Produces slow, steady responding

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Punishment

• A punishment is an event that decreases the frequency of the behavior it follow

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Physical Punishment for Children: Why Not?

1. Punishment teaches discrimination• rule learned: don’t swear at home but what you

desired was that they not swear at all.

2. Punishment can teach fear

3. Physical punishment may increase aggressiveness

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Physical Punishment for Children

• A single swat or two may be effective for 2 to 6-year-olds if:– The swat is only used for backup when milder

tactics fail– The swat is combined with reasoning and

reinforcing

• Remember: – Punishment tells you what not to do,

reinforcement tells you what to do

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Skinner’s Legacy: Controversy

Skinner argued that behaviors were shaped by external influences

instead of inner thoughts and feelings. Critics argued that Skinner dehumanized people by neglecting

their free will.

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Applications of Operant Conditioning

• In school: use individualized shaping to reinforce students starting with their current level of performance.

• At work: reinforce, even with a ‘good job’ for specific behaviors and achievements

• At home: be careful not to reward tantrums by giving in.

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Biological Constraints on Conditioning

• Each species is thought to come prepared to learn those things crucial to its survival.

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Limits on Classical Conditioning

• All conditioned stimuli are not equal

• Rats avoided a taste – but not sights or sounds – associated with being sick– Taste aversion: animals are biologically

predisposed to learn by eating food, not by the appearance of food, which foods make us sick.

• Is that why dogs and cats will eat their own vomit?

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Limits on Operant Conditioning

• Animals can most easily learn behaviors that draw on their predispositions– YES: Train a pigeon to flap wings to avoid a

shock, and peck to obtain food– NO: Train a pigeon to peck to avoid a shock,

and to flap wings to obtain food

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Cognitive Processes and Classical Conditioning

• Behaviorism: The view that (1) psychology should be an objective science that (2) studies behavior without reference to mental processes– Founded by Pavlov, Watson, and Skinner– Most psychologists today agree with (1) but not (2)

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Cognitive Processes and Operant Conditioning

• B. F. Skinner tried to downplay the role of cognitive processes. However, they cannot be ignored– Rats exploring a maze develop a cognitive

map, a mental representation of the maze. – Rats with experience in the maze exhibit

latent learning of the maze’s layout

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Cognitive Processes and Operant Conditioning

• Excess rewards can destroy intrinsic motivation, the desire to perform a behavior for its own sake.

• This is in contrast to extrinsic motivation, in which behavior is performed to gain reward or avoid punishment.

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Learning By Observation

• Cognition is a factor in observational learning, – in which humans and some other animals

learn by watching and imitating

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Observational Learning

• Bandura’s (1961) Bobo doll experiments showed the importance of modeling – the process of observing and imitating a specific

behavior

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Mirrors in the Brain

• Mirror neurons fire when we perform certain actions and when we observe others performing those actions

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Mirrors in the Brain

• If we see a loved one in pain, our face mirrors their expression, and so does our brain

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Applications of Observational Learning

• Models of prosocial behavior – can have prosocial effects.

• Unfortunately, antisocial behavior can also be learned by observation