copyright © allyn & bacon 2002 the world of psychology wood and wood learning chapter 5 this...

Copyright © Allyn & Bacon 2002

The World of PsychologyWood and Wood

Learning

Chapter 5

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Learning

When people think about academic Psychology this is usually what they picture.

A lot of the first “real” scientific Psychology was done on learning.

Probably the topic that moved Psychology from a branch of Philosophy to a branch of Physical Science.


Learning: Modern Definition

Learning may be defined as a relatively permanent change in behavior, knowledge, capability, or attitude that is acquired through experience and cannot be attributed to illness, injury, or maturation.


Measuring Learning: Problem Statement

Psychologists cannot observe learning directly but must infer that it has occurred.

They draw inferences from changes in observable behavior or in measurable capabilities and attitudes.


More Learning

Learning does not always result in an observable change in behavior. * Motivation – we “want” to Context – Only “fits in” occasionally Capability – Requires external conditions

* Note difference with textbook


How do organisms learn?

Through many different avenues. Habituation Classical conditioning Instrumental or operant conditioning Cognitive learning

1


How do organisms learn?

We will discuss

three basic forms of learning:

1. Classical conditioning

2. Operant conditioning

3. Observational learning (a type of cognitive learning).

2


DR. IVAN PAVLOV (1849-1936)

Classical Conditioning

Pavlov Conditioned Stimulus Unconditioned Stimulus Unconditioned Response Conditioned Response


Pavlov

Ivan Pavlov (1849–1936) organized and directed research in physiology at the Institute of Experimental Medicine in

St. Petersburg, Russia from 1891 until his death 45 years later.

Conducted experiments on the physiology of digestion

He won a Nobel Prize in 1904 First time Nobel Prize won by a Russian.


Careful Research Experimental apparatus eliminated:

Vibration, noise, temperature extremes, odors, drafts Nothing could influence the animals except the

conditioning stimuli to which they were exposed. (Schultz, 1975, pp. 187–188)

Dogs were isolated inside soundproof cubicles Dogs were put in harnesses to restrain their movements. Experimenters were in an adjoining cubicle Dogs were observed through a one-way mirror. Dogs were presented with food by remote control, Other conditioning stimuli also presented by remote control A tube carried the saliva from the dog’s mouth to a container where it

was measured.


The Apparatus


Definitions Related toClassical Conditioning

Classical conditioning: A learning process through which one stimulus comes to predict the occurrence of another stimulus and to elicit a response similar to or related to the response evoked by that stimulus.

Classical conditioning is sometimes referred to as respondent conditioning Pavlovian conditioning

Stimulus (STIM-yu-lus): Any event or object in the environment to which organism responds plural is stimuli.

Reflex is an involuntary response to a particular stimulus. Reflexes are made up of both a stimulus and a response.


Unconditioned Stimulus

Unconditioned means “not learned.”* Any stimulus that without learning will automatically

cause an unconditioned response is called an unconditioned stimulus (US).

Salivation in response to food is an unconditioned reflex because it is inborn, automatic, unlearned response to a

Unconditioned reflexes are “built into” NS* Differs from textbook


Examples ofUnconditioned Stimuli

loud noise startle light in eye pupil contraction puff of air in eye blink touching hot stove hand withdrawal

Is Chinese startle response learned? Others?


Unconditioned Response

Unconditioned Response (UR): A response that is invariably elicited by the unconditioned stimulus without prior learning.


Conditioned Reflex/Response

Conditioned Reflex:

A learned reflex rather than a

naturally occurring one.

This terminology is confusing! I prefer Conditioned Response.


Classical Conditioning Cont.

Important Terms: Extinction Spontaneous Recovery Generalization Discrimination Higher-Order Conditioning


Conditioned Stimulus

Conditioned means “learned.”*Any stimulus that comes to elicit a conditioned response through Classical Conditioning is called a conditioned stimulus (US).Salivation in response to food is an unconditioned reflex because it is

inborn, automatic,

unlearned response to aUnconditioned reflexes are “built into” NS


Classical Conditioning Simplified Pictorial View


Classical Conditioning: the Contemporary View

The Cognitive Perspective: Prediction is the critical element

Biological Predispositions: Their role in classical conditioning


Factors Influencing Classical Conditioning

How reliably the CS predicts the US The number of pairings of the CS and the US The intensity of the US The temporal relationship between

the CS and the US


Classical Conditioning:The Diagram

S1 R1S2

S2 R2

Evoked

Reflex PredictionPrediction

USUS URUR

CRCRCSCS

Sim

ilar

ElicitedConditioned

Unconditioned

Event or Object Organism responds to.

Event or Object Organism responds to.

Event or Object Organism Perceives.

Event or Object Organism Perceives.


End 5a


Higher-Order Conditioning

Classical conditioning is not limited to just two procedures: (1) by the pairing of a conditioned stimulus with an unconditioned stimulus (2) through generalization.

Classical conditioning can occur in another way: Higher-order conditioning.

Higher-order conditioning takes place when: a neutral stimulus is paired with an existing conditioned stimulus a neutral stimulus becomes associated with an existing conditioned stimulus a neutral stimulus gains the power to elicit the same conditioned response.

Higher-order conditioning can account for many of the positive and negative feelings toward stimuli that people associate with other people or situations.


Important Definitions

spontaneous recovery: The reappearance of an extinguished response (in a weaker form) when an organism is exposed to the original conditioned stimulus following a rest period.

generalization: In classical conditioning, the tendency to make a conditioned response to a stimulus similar to the original conditioned stimulus.

discrimination: The learned ability to distinguish between similar stimuli so that the conditioned response occurs only to the original conditioned stimulus but not to similar stimuli.

higher-order conditioning: Conditioning that occurs when a neutral stimulus is paired with an existing conditioned stimulus, becomes associated with it, and gains the power to elicit the same conditioned response.


Watson, Little Albert, and PeterOr Learning to Fear

In the laboratory, Rayner presented Little Albert with a white rat. As Albert reached for the rat, Watson struck the steel bar with a

hammer just behind Albert’s head. This procedure was repeated, and Albert “jumped violently, fell

forward and began to whimper” (Watson & Rayner, 1920, p. 4). A week later, Watson continued the experiment, pairing the rat

with the loud noise five more times. Then at the sight of the white rat alone, Albert began to cry.

Why we learned to dislike Watson.


Watson, Little Albert, and PeterOr Learning to Fear

When Albert returned to the laboratory 5 days later, the fear had generalized to: a rabbit somewhat less, to a dog, a seal coat, Watson’s hair,

and a Santa Claus mask.

After 30 days Albert’s fears were still evident, although less intense.

Albert moved away still afraid of fuzzy things

Why we learned to dislike Watson.


Other Considerations

The ideal time between conditioned and unconditioned stimuli is about 1/2 second varies according to the type of response being conditioned the nature and intensity of the conditioned stimulus the nature and intensity of the unconditioned stimulus

Some studies indicate that the age of the subject may also be a variable affecting the optimal time interval

If the conditioned stimulus occurs too long before the unconditioned stimulus, an association will not form.

The one notable exception to this general principle is conditioning of taste aversions.


Operant Conditioning

Thorndike’s Law of Effect Reinforcement Shaping Extinction Generalization and Discrimination


Thorndike and the Puzzle Box

American psychologist Edward Thorndike Preceded Pavlov designed and conducted experiments to study animal

intelligence. attempted to answer questions about the nature of learning

across animal species. investigated trial-and-error learning in cats, dogs, chicks, and

monkeys. best-known experiments placed a hungry cat in a wooden box

with slats called a puzzle box.After many trials, the cat learned through trial and error to open the

door almost immediately after being placed in the box.

http://fates.cns.muskingum.edu/~psych/psycweb/history/thorndike.htm


Thorndike’s Puzzle Box

http://fates.cns.muskingum.edu/~psych/psycweb/history/thorndike.htm#Theory




Thorndike’s law of effect

The consequence, or effect, of a response will determine whether the tendency to respond in the same way in the future will be strengthened or weakened.

Responses closely followed by satisfying consequences are more likely to be repeated.

Connections between a stimulus and a response will be strengthened if the response is followed by a satisfying consequence and weakened if the response is followed by discomfort.



Thorndike builds a Foundation

Thorndike (1898) insisted that it was “unnecessary to invoke reasoning” to explain how the learning took place.

Thorndike’s law of effect formed the conceptual starting point for B. F. Skinner’s work in operant conditioning.


Operant Conditioning

A type of learning in which the consequences of behavior are manipulated in order to increase or decrease that behavior

http://www.ship.edu/~cgboeree/skinner.html


Operant Vs Classical Conditioning In classical conditioning

Organism does not learn a new response O learns to make an old or existing response to a new stimulus. O cannot help but respond in expected ways. Classically conditioned responses are involuntary or reflexive Process begins with stimulus to evoke a reflexive response.

In operant conditioning O learns a new response O learns to apply voluntary responses. Response comes first, the consequence that follows tends to modify this response in

the future. Consequences of behavior manipulated to increase or decrease response frequency or

to shape an entirely new response. Behavior that is reinforced tends to be repeated. Process does not begin with a stimulus to elicit a response.


Operant Terms Definitions

A reinforcer is anything that strengthens or increases the probability of the response it follows. Behavior that is ignored or punished is less likely to be repeated.

shaping: An operant conditioning technique that consists of gradually molding a desired behavior (response) by reinforcing responses that become progressively closer to it.

Skinner box: A soundproof chamber with a device for delivering food and detecting behavior - usually automatically.



ReinforcementOne Dichotomy +/-

Positive - a reward that follows a response and increases the probability that the response will be repeated.

Negative - the termination of an unpleasant stimulus after a response that increases the probability that the response will be repeated.



Reinforcementanother Dichotomy

Primary - fulfills basic physical need for survival

Secondary - NS that becomes reinforcing after repeated pairings with other reinforcers.


Reinforcement Schedules(Partial Reinforcement)

Fixed-Ratio - reinforcer is given after a fixed number of correct responses

Variable-Ratio - reinforcer is given after a variable number of correct responses

Fixed-Interval - reinforcer is give after first correct response after passage of fixed interval of time

Variable-Interval - reinforcer is given after first correct response following a variable interval of time



Reinforcement Schedules

http://www.fiu.edu/orgs/psych/eab_3002/interact/schedule.htm

http://www.fiu.edu/orgs/psych/eab_3002/interact/schedule.htm



Shaping Just a Bit at a Time

B. F. Skinner developed this technique Particularly effective in conditioning complex behaviors. Process:

Don’t wait for desired response and then reinforcing it Reinforce any movement in the direction of desired response Gradually guide responses closer and closer to the goal.



The Textbook’s Skinner Box Bull

Skinner designed a soundproof apparatus, commonly called a Skinner box, with which he conducted his experiments in operant conditioning. One type of box is equipped with a lever, or bar, that a rat presses to gain a reward of food pellets or water from a dispenser. A record of the animal’s bar-pressing is registered on a device called a cumulative recorder, also invented by Skinner. Through the use of shaping, a rat in a Skinner box is conditioned to press a bar for rewards. It may be rewarded first for simply turning toward the bar. The next reward comes only when the rat moves closer to the bar. Each step closer to the bar is rewarded. Next the rat must touch the bar to receive a reward; finally, it is rewarded only when it presses the bar.



Skinner Boxhttp://www.biozentrum.uni-wuerzburg.de/genetics/behavior/learning/SkinnerBox.html

Click forGerman

Skinner BoxPhotos

Click forGerman

Skinner BoxPhotos

http://www.nici.kun.nl/~voogd/skinner/index.html


Skinner’s Version

One pleasant Saturday afternoon I surveyed my supply of dry pellets and, appealing to certain elemental theorems in arithmetic, deduced that unless I spent the rest of that afternoon and evening at the pill machine, the supply would be exhausted by ten-thirty Monday morning. Since I do not wish to deprecate the hypothetico-deductive method, I am glad to testify here to its usefulness. It led me to apply our second principle of unformalized scientific method and to ask myself why every press of the lever had to be reinforced. I was not then aware of what had happened at the Brown Laboratories, as Harold Schlosberg later told the story. A graduate student had been given the task of running a cat through a cat through a difficult discrimination experiment. One Sunday, the student found the supply of cat food exhausted. The stores were closed, and so, with a beautiful faith in the frequency-theory of learning, he ran the cat as usual and took it back to its living cage unrewarded. Schlosberg reports that the cat howled its protest continuously for nearly forty eight hours. Unaware of this, I decided to reinforce a response only once every minute and to allow all other responses to go unreinforced There were two results: (a) my supply of pellets lasted almost indefinitely, and (b) each rat stabilized at a fairly constant rate of responding. Now, a steady state was something I was familiar with from physical chemistry, and I therefore embarked upon the study of periodic reinforcement. I soon found that the constant rate at which the rat stabilized depended upon how hungry it was. Hungry rat, high rate; less hungry rat, lower rate. At that time I was bothered by the practical problem of controlling food deprivation. I was working half time at the Medical School (on chronaxie of subordinations) and could not maintain a good schedule in working with the rats. The rate of responding under periodic reinforcement suggested a scheme for keeping a rat at a constant level of deprivation. The argument went like this: Suppose you reinforce the rat, not at the end of a given period, but when it has completed the number of responses ordinarily emitted in that period. And suppose you use substantial pellets of food and give the rat continuous access to the lever. Except for periods when the rat sleeps, it should operate the lever at a constant rate around the clock. For, whenever it grows hungrier, it will work faster, get food faster, and become less hungry, while whenever it grows slightly less hungry, it will respond at a lower rate, get less food, and grow hungrier. By setting the reinforcement at a given number of responses, it should even be possible to hold the rat at any given level of deprivation. I visualized a machine with a dial which one could set to make available, at any time of day or night, a rat in a given state of deprivation. Of course, nothing of the sort happens. This is fixed-ratio rather than fixed- interval' reinforcement and, as I soon found out, it produces a very different type of performance. This is an example of a fifth unformalized principle of scientific c practice, but one which has at least been named. Walter Cannon described it with a word invented by Horace Walpole:serendipity the art of finding one thing while looking for something else.



Superstitious Behavior

Sometimes a reward follows a response but the two are not related.

Superstitious behavior occurs if an individual falsely “believes” that a connection exists between an act and its consequences.



Extinction

Responses followed by reinforcers tend to be repeated and responses no longer followed by reinforcers will occur less and less frequently and eventually die out.

In operant conditioning, extinction occurs when reinforcers are withheld.

Spontaneous recovery also occurs in operant conditioning.



Generalization and Discrimination

Generalization occurs in operant conditioning. Generalization occurs when a reinforced stimuli causes

response to non reinforced stimuli which have common characteristics.

Discrimination in operant conditioning involves learning to distinguish between a stimulus that has been reinforced and other stimuli that may be very similar.

Discrimination is learned when the response to the original stimulus is reinforced but responses to similar stimuli are not reinforced.



Factors Influencing Operant Conditioning

The magnitude of reinforcement

The immediacy of reinforcement

The level of motivation of the learner



Other Issues in Operant Conditioning

Punishment Escape Learning Avoidance Learning Learned Helplessness Biofeedback Behavior Modification


Comparison


Cognitive Learning

Insight Latent Learning Cognitive Maps Observational Learning

Learning Aggression


Post Pavlov and Skinner

A growing number of psychologists stress the role of mental processes. broaden the study of learning to include such

cognitive processes as: thinking, knowing, problem solving, remembering, forming mental representations.

According to cognitive theorists, these processes are critically important in a more complete, more comprehensive view of learning.

http://www.renardus.org/cgi-bin/genDDCbrowseSQL.pl?node=AACCQ


Insight

The sudden realization of the relationship between elements in a problem situation, which makes the solution apparent.

http://sun.science.wayne.edu/~wpoff/cor/mem/cogninst.htmlhttp://www.ship.edu/~cgboeree/insight.html (Gestalt View of Insight)


Latent Learning

Learning that occurs without apparent reinforcement but that is not demonstrated until sufficient reinforcement is provided.

http://website.lineone.net/~nene/learning.htmhttp://sun.science.wayne.edu/~wpoff/cor/mem/cognlatn.html

A NEW FORMULA FOR BEHAVIORISM [1]Edward Chace Tolman (1922)

First published in Psychological Review, 29, 44-53.

A NEW FORMULA FOR BEHAVIORISM [1]Edward Chace Tolman (1922)

First published in Psychological Review, 29, 44-53.

http://website.lineone.net/~nene/learning.htm

http://sun.science.wayne.edu/~wpoff/cor/mem/cognlatn.html


Cognitive Maps

A mental representation of a spatial arrangement such as a maze.

COGNITIVE MAPS IN RATS AND MEN[1] Edward C. Tolman (1948)

First published in The Psychological Review, 55(4), 189-208.

COGNITIVE MAPS IN RATS AND MEN[1] Edward C. Tolman (1948)

First published in The Psychological Review, 55(4), 189-208.

http://www.cogs.susx.ac.uk/lab/nlp/gazdar/teach/atc/1999/web/verenah/http://www.alleydog.com/cognotes/cogmap.htmlhttp://www.people.memphis.edu/~kshawes/cogmap/1


Observational Learning

Learning by observing the behavior of others and the consequences of that behavior; learning by imitation.

Another name for observational learning: modeling Also called Social Learning Theory Occurs when an observer's behavior changes after

viewing the behavior of a model. http://www.funderstanding.com/observational_learning.cfmhttp://mentalhelp.net/psyhelp/chap4/chap4g.htm


Observational Learning 2

Model: The individual who demonstrates a behavior or serves as an example in observational learning.

Note: Models may also be physical constructs that demonstrate a behavior, process, method, or result.


End Chapter 5

copyright © allyn & bacon 2002 the world of psychology wood and wood learning chapter 5 this...

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