Learning Psychology: A Concise Introduction 2 nd Edition Richard Griggs Chapter 4 Prepared by J. W. Taylor V.

Learning

Psychology: A Concise Introduction

2nd Edition

Richard Griggs

Chapter 4

Prepared byJ. W. Taylor V

Different Perspectives

Behavioral psychologists have focused on the learning of associations through classical conditioning and operant conditioning

Cognitive psychologists studying learning are interested in the more complex type of earning involved in human memory

The Journey…

Learning Through Classical Conditioning

Learning Through Operant Conditioning

Biological and Cognitive Aspects of Learning

Learning Through Classical Conditioning

Learning Through Operant Conditioning

Biological and Cognitive Aspects of Learning

Learning Through Classical Conditioning

The Elements and Procedures of Classical Conditioning

General Learning Processes in Classical Conditioning

Classical Conditioning

The process of learning in which one stimulus signals the arrival of another stimulus

Sometimes called “Pavlovian” conditioning because Ivan Pavlov was the first researcher to systematically study this type of learning

Pavlov A Russian physiologist studying digestive

processes in dogs The dogs were strapped into harnesses and had tubes

inserted into their cheeks to measure the amount of salivation, the initial step in the digestive process

With time, he noticed that the dogs started to salivate before the meat powder was even put in their mouths, and wanted to know why this was happening

Elements and Procedures of Classical Conditioning

Unconditioned Stimulus

(UCS)

Unconditioned Stimulus

(UCS)

Unconditioned Response

(UCR)

Unconditioned Response

(UCR)

Conditioned Stimulus

(CS)

Conditioned Stimulus

(CS)

Conditioned Response

(CR)

Conditioned Response

(CR)

Associated Similar

UCS and UCR

Dogs salivate when meat powder is put in their mouths – this is a reflex, a response that occur automatically in the presence of a certain stimulus (i.e., meat powder)

An unconditioned stimulus (UCS) is the stimulus that elicits the reflexive response (here, the UCS is the meat powder)

An unconditioned response (UCR) is the response automatically elicited by the UCS (here, the UCR is salivating in response to the meat powder)

CS and CR

A neutral stimulus is a stimulus that does not naturally elicit the to-be-conditioned response (e.g., auditory tones)

To achieve conditioning, the neutral stimulus (a tone) is presented just before (ideally one-half to one full second before) the UCS (meat powder) for several trials

Once the conditioning occurs (that is, the dog starts to salivate to the sound of the tone before the food is put in its mouth), the neutral stimulus is called the conditioned stimulus (CS)

The learned response to the conditioned stimulus is called the conditioned response (CR)

Delayed and Trace Conditioning

In delayed conditioning, the offset of the CS is delayed until after the UCS is presented so that the two stimuli occur at the same time The tone would be turned on and continue to sound until the

meat powder was placed in the dog’s mouth

In trace conditioning, there is a period of time between the offset of the CS and the onset of the UCS when neither stimulus is present It is called “trace” conditioning because there must be a memory

trace of the CS for the association between stimuli to be learned

Delayed conditioning is the most effective procedure for classical conditioning; trace conditioning can be effective provided the interval between stimuli is brief

A Summary of Classical Conditioning

The “Little Albert” Study

John Watson and Rosalie Rayner conducted a study on an 11-month-old infant named Albert

While Albert was looking at a little white rat, Watson quietly sneaked behind him with a long iron bar and a hammer and clanged the two together

Albert’s reflexive response, the UCR, was a fear-avoidance response (e.g., crying and trying to crawl away) to the loud noise, which was the UCS

After pairing the white rat with the unexpected loud noise only 7 times, the white rat became a CS

Other Evidence

Elise Bregman was unable to condition infants to fear inanimate objects such as wooden blocks and cloth curtains, suggesting possible biological predispositions to learn certain fears easier than others

Classical conditioning can be used to condition positive reactions, such as in advertising to condition positive attitudes and feelings toward certain products (e.g., a celebrity serves as a UCS, and the product as the CS)

ExtinctionExtinction

SpontaneousRecovery

SpontaneousRecovery

General Learning Processes in Classical Conditioning

Acquisition is the process of acquiring a new response, that is, a CR to a CS The strength of the CR increases during acquisition

Other processes:

StimulusGeneralization

StimulusGeneralization

StimulusDiscrimination

StimulusDiscrimination

Extinction

A CS must reliably signal that the UCS is coming

Extinction is the disappearance of the CR when the UCS no longer follows the CS The strength of the CR decreases during

extinction

Spontaneous Recovery

During the extinction process, however, the CR mysteriously increases somewhat in strength following a rest interval

This is called spontaneous recovery As extinction continues, the recovery observed

following rest intervals continues to decrease until it is minimized

Acquisition, Extinction, and Spontaneous Recovery

Stimulus Generalization

Stimulus generalization is giving the CR to a stimulus similar to the CS

The more similar the stimulus is to the CS, the stronger the response will be

For example, if a dog learns to bark at the door bell, she may, at least in a new home, also bark at the telephone because both stimuli are ringing noises

This is an adaptive process because classical conditioning would not be very useful if it only allowed us to learn relationships between specific stimuli

Stimulus Discrimination

Overgeneralizing a response may not be adaptive, however; thus, we need to learn to discriminate among stimuli

Stimulus discrimination is learning to give the CR only to the CS or only to a small set of very similar stimuli including the CS For example, after being in her

new home for a period of time, the dog will learn to differentiate/discriminate between the door bell and the phone ringing noises

Discrimination Training

During discrimination training, you present many different stimuli numerous times, but the UCS only follows one CS This procedure will extinguish the responses to

other stimuli

Stimulus Generalization and Discrimination

Learning Through Operant Conditioning

Learning Through Reinforcement and Punishment

General Learning Processes in Operant Conditioning

Partial-Reinforcement Schedules in Operant Conditioning

Motivation, Behavior, and Reinforcement

Operant Conditioning

Behaviors that are reinforced (lead to satisfying consequences) will be strengthened, and behaviors that are punished (lead to unsatisfying consequences) will be weakened

Called “operant” conditioning because the organism needs to “operate” on the environment to bring about consequences from which to learn

Learning to associate behaviors with their consequences

The Law of Effect

Thorndike’s Law of Effect states that any behavior that results in satisfying consequences tends to be repeated, and any behavior that results in unsatisfying consequences tends not be repeated

Learning Through Reinforcement and Punishment

A reinforcer is a stimulus that increases the probability of a prior response

Reinforcement is the process by which the probability of a response is increased by the presentation of a reinforcer following the response For example, if you operantly

condition your dog to bark by giving her a treat each time she “speaks,” the food would be a reinforcer, and the process of increasing the dog’s speaking behavior by using this reinforcer would be called reinforcement

Learning Through Reinforcement and Punishment

A punisher is a stimulus that decreases the probability of a prior response

Punishment is the process by which the probability of a response is decreased by the presentation of a punisher following the response For example, if you conditioned your

dog to stop getting up on the couch by spraying her with water each time she got up on the couch, the spraying would be the punisher, and the process of decreasing her couch jumping behavior would be called punishment

Positive and Negative

Positive means that a stimulus is presented In both positive reinforcement and positive

punishment, a stimulus presented Negative means that a stimulus is removed

In both negative reinforcement and negative punishment, a stimulus is removed

Appetitive and Aversive

An appetitive stimulus is a stimulus that an organism finds pleasing (e.g., food, money)

An aversive stimulus is a stimulus that an organism finds unpleasing (e.g., sickness, social isolation)

Appetitive and Aversive

Consequently... In positive reinforcement, an appetitive stimulus

is presented (e.g., praise for good work) In positive punishment, an aversive stimulus is

presented (e.g., scolding for doing poor work) In negative reinforcement, an aversive stimulus

is removed (e.g., using a heating pad for a sore back)

In negative punishment, an appetitive stimulus is removed (e.g., parents taking away desert from a child)

Positive and Negative Reinforcement and Punishment

Positive Negative

ReinforcementAppetitive stimulus

presented

Aversive stimulus removed

PunishmentAversive stimulus

presented

Appetitive stimulus removed

How do we know?

In any example of positive or negative reinforcement or punishment, it is critical to realize that we only know if a stimulus has served as a reinforcer or a punisher and led to reinforcement or punishment if the behavior happens again or stops happening

Primary and Secondary Reinforcers

A primary reinforcer is innately reinforcing since birth (e.g., food, social contact)

A secondary reinforcer is not innately reinforcing, but gains reinforcing properties through learning (e.g., money, good grades)

General Learning Processes in Operant Conditioning

Shaping occurs when an animal is trained to make a particular response by reinforcing successively closer approximations to the desired response With humans, this might mean reinforcing a child the closer he

comes to making his bed correctly each morning Responding in an operant conditioning

experiment is depicted in a cumulative record – a record of the total number of responses over time It is a visual depiction of the

rate of responding As the slope of a line in a cumulative

record gets steeper, the response rate is faster

How to Understand a Cumulative Record

Acquisition, Extinction, and Spontaneous Recovery

Acquisition refers to the strengthening of the reinforced operant response

Extinction is the disappearance of the operant response when it is no longer reinforced The decreasing slope of the record indicates that

the response is being extinguished (i.e., there are fewer and fewer responses over time)

Spontaneous recovery is the temporary recovery of the operant response following a break during extinction training

Acquisition, Extinction, and Spontaneous Recovery

Vending Machines

We learn that by putting money into a vending machine, we get something we really like. We acquire the response of inserting money into this particular machine.

But one day, we put money in and get no food out. This happens again. Soon, we stop putting money in the vending machine. Our response is being extinguished.

However, after a period of time, we go back and try again (spontaneous recovery). If the machine has been repaired, we will get our food, and our response rate returns to its previous level. If not, we continue along our extinction trail.

Discrimination and Generalization A discriminative stimulus is one that has to be present for the

operant response to be reinforced It “sets the occasion” for the response to be reinforced For example, a rat learns that pressing a lever will result in food only

when a light is on, but not when the light is off Stimulus generalization is the giving the operant response in

the presence of stimuli similar to the discriminative stimulus For example, the rat learns to press

the lever for food only when the light is a certain shade of red. Presentation of different colored lights following acquisition constitutes a test for generalization.

Partial-Reinforcement Schedules in Operant Conditioning

Reinforcing every response is called a continuous schedule of reinforcement

Partial schedules of reinforcement reinforce behavior only part of the time The partial-reinforcement effect states that responses

that are reinforced according to a partial schedule rather than a continuous schedule are more resistant to extinction

Partial-Reinforcement Schedules

A ratio schedule is based on the number of responses made

An interval schedule is based on the amount of time that has elapsed

In a fixed schedule, the number of responses required for a ratio schedule or the amount of time needed for an interval schedule is fixed

In a variable schedule, the number of responses required for a ratio schedule and amount of time for an interval schedule varies on each trial

Ratio Schedules

In a fixed ratio schedule, a reinforcer is delivered after a fixed number of responses are made (e.g., a rat has to press a lever 10 times before receiving the reinforcer of food)

In a variable ratio schedule, the number of responses it takes to obtain a reinforcer varies on each trial but averages out to be a certain number over trials (e.g., slot machine payoffs)

Fixed Ratio and Variable Ratio Schedules of Partial Reinforcement

Interval Schedules

In a fixed interval schedule, a reinforcer is delivered after the first response is given once a set interval of time has elapsed (e.g., periodic exams in a class, with most behaving/studying occurring right before the exam/reinforcer)

In a variable interval schedule, a reinforcer is delivered after a different time interval on each trial, but the time intervals over trials average to be a set time (e.g., pop quizzes)

Fixed Interval and Variable Interval Schedules of Partial Reinforcement

Which is best?

Ratio schedules lead to higher rates of responding than interval schedules (steeper slopes on the cumulative record)

Variable schedules lead to fewer breaks (no responding occurring) after reinforcement than fixed schedules

With respect to extinction, it will take longer to extinguish a response with a partial-reinforcement schedule than a continuous reinforcement

Motivation, Behavior, and Reinforcement

Motivation is the set of internal and external factors that energize our behavior and direct it toward goals

Theories of Motivation Drive-reduction theory proposes that first,

a bodily need (such as hunger) creates a state of bodily tension called drive; then, a motivated behavior (seeking food) works to reduce this drive by obtaining reinforcement (food) to eliminate this need and return the body to a balanced internal state. In essence, we are “pushed” into action

by unpleasant drive states Effective at explaining biological needs

such as hunger and thirst

Theories of Motivation

Incentive theory proposes that we are “pulled” into action by incentives, external environmental stimuli that do not involve drive reduction

For instance, students may be motivated by getting good grades, leading them to work and study hard

Money is another classic example of an incentive that “pulls” us into behaving in certain ways

Theories of Motivation

Arousal theory contends that our behavior is motivated to maintain an optimal level of arousal, which varies among people When below the optimal level, we are motivated to

raise our arousal to that level When over-aroused, we are motivated to lower our

arousal level to our optimal level of arousal Arousal theory argues that our level of arousal impacts

our performance level, with a certain level being optimal

The Yerkes-Dodson’s Law

Increased arousal will aid performance up to a point, after which further arousal impairs performance

Increased arousal will aid performance up to a point, after which further arousal impairs performance

Extrinsic vs. Intrinsic Motivation

Extrinsic motivation is the desire to perform behavior to obtain an external reinforcement or to avoid an external aversive stimulus

Intrinsic motivation is the desire to perform a behavior effectively and for its own sake Reinforcement is provided by the activity itself

For example, why do students study for classes? An extrinsic motivator would be grades An intrinsic motivator would be enjoyment of the

information

The Overjustification Effect

In a study by Lepper, Greene, and Nisbett (1973), some children who enjoyed playing with felt-tipped pens (they did so during free-play periods and were hence initially intrinsically motivated) were subsequently given prizes, an extrinsic incentive, for playing with the pens. Other such children were not given prizes for playing with the pens.

The Overjustification Effect

A week later, when no prizes were give for playing with the pens, the children who had not received prizes a week earlier still continued to play with the pens, but children who had been given prizes spent much less time playing with the pens.

The Overjustification Effect

Occurs when there is a decrease in an intrinsically motivated behavior after the behavior is extrinsically reinforced and then the reinforcement discontinued

The overjustification effect indicates that a person’s cognitive processing is influencing their behavior and that such processing may lessen the effectiveness of extrinsic reinforcers

However, extrinsic reinforcement is not likely to impact intrinsic motivation if the extrinsic reinforcement is dependent upon doing something well versus just doing it

Biological and Cognitive Aspects of Learning

Biological Preparedness in Learning

Latent Learning and Observational Learning

Biological Preparedness in Learning

Our preparedness to learn to fear objects dangerous to us (e.g., heights) and to avoid foods and drinks that make us sick has adaptive significance

Taste Aversion

Garcia and Koelling (1966) were studying the effects of radiation on rats

After several radiation treatments, the rats would still go into their experimental cages where they had been radiated, but would no longer drink the water in their experimental cages

Taste Aversion

The researchers discovered that the water bottles in the experimental cages were made of a different substance than those in the home cages – plastic versus glass

Thus, the water had a different taste in the two cages, and the rats quickly learned an aversion to the experimental cage water bottles, even though the sickness came hours after being in the experimental cages

Taste Aversion

Thus, taste aversion is a dramatic counterexample to the rule that the UCS (sickness) must immediately follow the CS (the different tasting water) for learning to happen

The rats did not learn taste aversion for any pairing of cue and consequence…

Taste Aversion

The researchers examined two cues that were both paired with sickness through radiation: Sweet-tasting water Normal tasting water with clicking noises and flashing lights

occurring when the rats drank the water The rats that drank the sweet-tasting water easily

learned the aversion to the water, but the rats that drank normal-tasting water while they experienced clicking noises and flashing lights did not do so The rats just couldn’t learn to pair these environmental

auditory and visual cues that occurred during their drinking with their later sickness; this pairing did not make any “biological” sense to the rats

Instinctual Drift

The tendency of an animal to drift back from learned operant response to an object to an innate, instinctual response

Thus, biologically instinctual responses sometimes limit or hinder our ability to condition other less natural responses

Organisms will learn certain association (those consistent with their natural behavior) more easily than others (those less consistent with their natural behavior)

Latent Learning and Observational Learning

Latent learning is learning that occurs but is not demonstrated until there is incentive to do so For example, students study for classes, but do not

openly demonstrate learning until an exam, for which the incentive is a good grade

Observational learning (modeling) is learning by observing others and imitating their behavior

Latent Learning

Edward Tolman was a pioneer researcher on latent learning

Food-deprived rats had to negotiate a maze, and the number of wrong turns/errors was counted For example, in a three-group

experiment, food (reinforcement) was always available in the goal box at the maze’s end for one group but never available for another group. For a third group, no food was available until the 11th day of the experiment.

Interestingly, the performance for the group that only started getting food reinforcement on the 11th day improved immediately on the next day equal to that of the group that had always gotten food reinforcement Thus, it appears that they had been

learning the maze all along, but did not demonstrate their learning until the incentive was made available

Latent Learning

Latent Learning

Albert Bandura’s pioneering research on modeling In one experiment, some children were exposed to an adult

who beats, kicks, and yells at a Bobo doll After observing this behavior, a child is taken to another room

filled with many appealing toys, but is told the toys are for other children and s/he cannot play with them

Later, the child goes to another room with toys s/he can play with, including a Bobo doll

The child proceeds to beat the Bobo doll in much the same way the adult model did

However, when exposed to a gentle model, children acted more gently toward the doll than children exposed to model

Thus the children’s behavior was guided by the behavior of the model to which they were exposed

Observational Learning

Observational Learning

In another experiment, an adult was rewarded for aggressive behavior, punished for aggressive behavior, or received no consequences at all

The children who saw the adult get reinforced for aggressive behavior acted more aggressively toward the Bobo doll than those who had seen the model act with no consequences

In addition, the children who had watched the adult get punished were less likely to act aggressively toward the doll than children who had not been exposed to any consequences for acting aggressively toward the doll