Chapter 5 Learning

Yonghui Wang School of Psychology

Shaanxi Normal University

2010.10.12

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Chapter 5 Learning

Learning is a fundamental topic for psychologists and plays a central role in almost every specialty area of psychology.

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Chapter 5 LearningOur goals: Identify four elements of Classical conditioning Explain these processes: extinction, spontaneous

recovery, stimulus generalization, discrimination. Distinguish between classical and operant

conditioning. Explain the principle of reinforcement. Define

primary reinforcer and secondary reinforcer. Distinguish four schedules of reinforcement, and

give examples of each. Distinguish positive reinforcement, negative

reinforcement, punishment. Distinguish between cognitive learning and

traditional theories of conditioning.

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Chapter 5 Outline

What sort of learning does classical conditioning explain?

How do we learn new behaviors by operant conditioning?

How does cognitive psychology explain learning?

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What is learning? Learning: A lasting change in behavior

or mental processes that results from experience.

How do we know when a behavior has been influenced by learning——or even is a result of learning?

Part of the answer relates to the nature-nurture question. The acquisition of behaviors, experience is

the “nurture” part. Inherited, genetic factors represent the

“nature” part.

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What is learning? Some forms of learning

Simple Habituation （习惯化）

Habituation is an extremely simple form of learning, in which an animal or a baby, after a period of exposure to a stimulus, stops responding.

Habituation is important in filtering the large amounts of information received from the surrounding environment.

Mere exposure effect （单纯接触效应） (i.e. the advertising of McDonald’s)

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What is learning?

Some forms of learning Simple Classical conditioning （经典条件反射） Operant conditioning （操作条件反射） Cognitive learning （认知学习）

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Classical conditioning

Classical conditioning （经典条件反射） is a basic form of learning in which a stimulus that produces an innate reflex becomes associated with a previously neural stimulus, which then acquires the power to elicit essentially the same response.

Ivan Pavlov, a Russian physiologist

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Pavlov's Conditioning Experiments

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Classical conditioning Some important terms

Neutral stimulus (NS) （中性刺激） Any stimulus that produces no conditioned

response prior to learning. When it brought into a conditioning experiment, the researcher will call it a conditioned stimulus.

Unconditioned stimulus (UCS, or US) （非条件刺激）

The stimulus that elicits an unconditioned response (without having been learned).

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Classical conditioning Unconditioned response (UCR, or UR) （非条

件反应） The response elicited by an

unconditioned stimulus without prior learning (e.g., salivation at the smell of food).

Conditioned stimulus (CS) （条件刺激） A once-neutral stimulus that has been

paired with an unconditioned stimulus to bring about a response formerly caused only by the unconditioned stimulus.

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Classical conditioning Conditioned response (CR) （条件反

应） A response elicited by a previously

neutral stimulus that has become associated with the unconditioned stimulus ( e.g., salivation at the ringing of a bell).

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Classical conditioning

Can you give some examples of classical conditioning?

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Phases of Classical Conditioning

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Elements of Classical Conditioning Unconditioned stimulus

Unlearned, inborn, innate Unconditioned response

Response to unlearned stimulus Conditioned stimulus

Stimulus that is learned Conditioned response

Response to learned stimulus

Can you figure out the relationship between stimuli and responses?

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Components of Classical Conditioning

Acquisition （习得） The initial learning stage in classical

conditioning, during which the conditioned response comes to be elicited by the conditioned stimulus.

Stimulus Generalization （泛化） The extension of a learned response to

stimuli that are similar to but different from the conditioned stimulus.

for example

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Components of Classical Conditioning

Stimulus Discrimination （分化） A change in responses to one

stimulus but not to stimuli that are similar.

for example Extinction （消退）

The weakening of a conditioned response in the absence of an unconditioned stimulus.

for example

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Components of Classical Conditioning

Has it vanished forever once a conditioned response has been extinguished? Good news: not necessary.

Spontaneous Recovery （自发恢复） The reappearance of an extinguished

conditioned response after a time delay.

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Components of Classical Conditioning

Spontaneous Recovery （自发恢复）

Acquisition

Extinction

Spontaneous recovery

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Applying Conditioning Principles to Human Behavior

Can you recall some Applications of classical conditioning?

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Challenging basic assumptions

Cognitive psychology Learns actively develop an

expectancy about the relationship between the unconditioned stimuli and conditioned stimuli.

Recall the classical conditioning first

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Learning psychology (John Garcia) The experience of the rats

a) violated one of the basic rules—that an unconditioned stimulus should immediately follow a conditioned stimulus. The interval can as long as eight hours.

b) The conditioning sometimes occurred after just one exposure to water that was followed later on by illness.

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Classical Conditioning Is Selective Research demonstrating that we

develop phobias about snakes and spiders, for example, but almost never about flowers or cooking utensils illustrates Seligman's principles of preparedness and contrapreparedness, respectively.

The ease with which we develop conditioned food (or taste) aversions also illustrates learning preparedness.

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Conditioned food aversions are exceptions to the general rules about classical conditioning. Animals can learn to avoid poisonous food even if there is a lengthy interval between eating the food and becoming ill. In many cases, only one pairing of conditioned and unconditioned stimuli is necessary for learning to take place.

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Thorndike's law of effect

Look at this experiment at first.

Law of effect （效果律）

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Skinner’s box

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Operant Conditioning Operant conditioning, or

instrumental conditioning is learning in which a voluntary response is strengthened or weakened, depending on its favorable or unfavorable consequences.

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Components of Operant Conditioning

Reinforcement and Reinforcer （强化和强化物） Positive reinforcement and positive reinforcers Negative reinforcement and negative

reinforcers Punishment （惩罚）

The punishment dilemma （惩罚的两难选择） Shaping （塑造）

The process of teaching a complex behavior by rewarding closer and closer approximations of the desired behavior.

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Reinforcement and Reinforcer Reinforcement

The process by which a stimulus increases the probability that a preceding behavior will be repeated.

Reinforcer Any stimulus that increases the

probability that a preceding behavior will occur again.

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Reinforcement and Reinforcer Positive reinforcer

A stimulus added to the environment that brings about an increase in a preceding response.

Negative reinforcer An unpleasant stimulus whose

removal leads to an increase in the probability that a preceding response will occur again in the future.

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Reinforcement and Reinforcer Primary reinforcer

A reinforcer that can satisfy a basic biological need, most likely food or water.

Secondary reinforcers The reinforcers that do not satisfy a

basic biological need but acquire their rewarding power by association with another established reinforcer.

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Punishment

The pros and cons of punishment Advantage

Should be swift, sufficient Protection

Disadvantage Not as effective as reinforcement Not usually permanent Not convey any information of alternative

behavior May result in anxiety of aggressive behavior

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Punishment

Question

When should we use punishment and when the reinforcer?

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Schedules of Reinforcement Continuous reinforcement （持续强化） Partial reinforcement （部分强化）

Fixed-ratio schedule （比率固定） Variable-ratio schedule （比率不定） Fixed-interval schedule （间隔固定） Variable-interval schedule （间隔不定）

Can you give examples of each schedule?

Number of responses

Amount of time

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Schedules of Reinforcement

What are the characters of each schedule?

Which one is better?

Can you design a plan for more efficiency?

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The Application of Operant Conditioning

Computer-Assisted Instruction (CAI) （计算机辅助教学） Students learn at their own rate, using

computers that are programmed to deliver individual instruction.

Behavior Modification （行为矫正） A formalized technique for promoting the

frequency of desirable behaviors and decreasing the incidence of unwanted ones.

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Comparing Classical And Operant Conditioning

Similarities involve associations between stimuli and

responses subject to extinction and spontaneous

recovery as well as generalization and discrimination.

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Comparing Classical And Operant Conditioning

Differences The stimuli is before response in Classical

Conditioning, while stimuli is after response in Operant Conditioning.

The stimuli (food) in Classical Conditioning is using as UCS, while stimuli is after response serve as a reinforce in Operant Conditioning.

The response is more ”voluntary” in Operant Conditioning.

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Cognitive-Social Approaches to Learning Latent Learning and Cognitive Maps

Learning takes place before the subject realizes it Cognitive map is latent learning stored as a mental image

Insight and Learning Sets Learning seems to occur in a “flash” with insight Learning sets refer to increasing effectiveness at problem solving through experience

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Learning by Observing Observational or vicarious learning （观察学

习或替代学习） Social learning theorists Vicarious reinforcement or vicarious

punishment

Cognitive-Social Approaches to Learning

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Learning by Observing

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Learning by Observing

Results

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Learning by Observing

Social learning theory argues that we learn not just from firsthand experience, but also from watching others or by hearing about something. Albert Bandura contends that observational (or vicarious) learning accounts for many aspects of human learning.

The extent to which we display behaviors that have been learned through observation can be affected by vicarious reinforcement and vicarious punishment.