learning theories of hb

7/30/2019 Learning Theories of HB

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H U M A N B E H A V I O R

LISA J. MERLO, PH.D.

Learning Theories
http://www.ufl.edu/


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Objectives

Understand theory of Classical Conditioning

Applications to clinical practice

Understand theory of Operant Conditioning Applications to clinical practice

Understand theory of Social Learning Applications to clinical practice

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Classical Conditioning


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Learning what events signal:

Lightning thunder

Sour-smelling milk bad taste

Unexpected loud noise startle response

Chopping onions tears

The scientific study of simple associations led to thedevelopment of classical conditioning theory

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Ivan Pavlov5

Russian physiologist studyingthe digestive system

Studied the role of saliva inthe digestive process

Developed method to

measure saliva production


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Salivary Conditioning Apparatus6

Gave dog food and recorded salivation while it ate


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Pavlovs Saliva Research

Pavlovs Problem: experienced dogs salivatedbefore the food was presented

Pavlovs Theory: Some stimulus that precededthe food presentation had acquired capacity toelicit the response of salivation Dogs were exhibiting a simple type of learning

This type of learning is the foundation forClassical Conditioning

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Pavlovs Experiments

Pavlov conducted experiments to test his new theoryof learning

Studied the effect of different stimuli on the behaviorof interest (AKA, response)

Animals automatically demonstrated the response afterexposure to some stimuli

Animals did not demonstrate the response after exposure toother stimuli

Animals could be taught to demonstrate the response tosome stimuli by pairing them with others

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Paradigm of Classical Conditioning

1st: Select a stimulus that automatically elicits acharacteristic response Stimulus =Unconditioned stimulus (US)

Response = Unconditioned response (UR) Unconditioned means the stimulus-response connection is

innate

2nd: Select a Stimulus for Conditioning (CS) Conditioned Stimulus (CS) Can be any reasonable

stimulus that does not initially evoke the UR Conditioned means the stimulus-response connection occurs

only AFTER the conditioning procedure takes place

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Classical Conditioning & Pavlovs Dogs10


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Key Definitions

Unconditioned Stimulus (US) - stimulus whichnaturally triggers a response [food]

Unconditioned Response (UR) - unlearned, naturalresponse to the US [salivating]

Conditioned Stimulus (CS) - previously neutral

stimulus, which eventually triggers a response [bell]

Conditioned Response (CR) - learned response to apreviously neutral stimulus [salivating]

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Cognitive Factors Are Ignored12


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Factors Affecting Classical Conditioning

The CS should be presented BEFORE the US

The US should follow the CS closely in time

Short delay = best

Trace (moderate delay) = more difficult to achieve CR

Long delay = difficult to achieve CR

Simultaneous = much weaker conditioning than short delay

Backward (i.e., US then CS) = usually not effective

The CS should UNIQUELY predict the US It should provide new information suggesting that the US is

about to occur

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Higher Ordering Conditioning

Second Order Conditioning: CR transferred from oneCS to another CS

Example Food (US) paired with metronome ticking (CS) to establish first-

order conditioning

Food (US)

Salivation (UR) Eventually, ticking (CS) Salivation (CR)

Ticking (CS) paired with black square (2nd CS) to establish second-order conditioning Black Square Ticking (CS) Salivation (CR) Eventually, black Square (2nd CS) Salivation (CR) --- despite never being

paired with food (US) Can also be done (less successfully) with 3rd order

conditioning Key point: US does not always need to be present to establish

association; Allows more flexibility in learning opportunities

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Second-Order Classical Conditioning15


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Little Albert & Stimulus Generalization16

Little Albert (11 months) was afraid ofnothing, except a loud sound made bystriking a steel bar. This made him cry.

By striking the bar at the same time thatAlbert touched a white rat, the fear

transferred to the white rat (classicalconditioning).

After 7 combined stimulations (rat + sound),Albert remained greatly disturbed at thesight of a rat, but the fear also spread to

include: a white rabbit, cotton, wool, a furcoat, a dog, a Santa Clause mask, and theexperimenters hair.

The fear did not transfer to his woodenblocks or other objects dissimilar to the rat.


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Generalization and Discrimination

Generalization: Transfer of the effects ofconditioning to similar stimuli In general, the more similar a stimulus is to the training

stimulus, the greater its capacity to elicit a conditioned

response

Discrimination: Subject responds to a newstimulus differently than he responds to an

established conditioned stimulus

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Extinction

Conditioning is not necessarily permanent

Extinction occurs when the CS is presentedrepeatedly without the US (e.g., bell without food)

CS no longer signals the US, so conditionedresponding gradually diminishes

But CS-US association is not erased completely

Spontaneous recovery

Rapid Reacquisition

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Spontaneous Recovery

Spontaneous recovery = reappearance of anextinguished response

Example: following one day of extinction trails (i.e.,presenting CS without US until no CRs are present),the CR will be present again the following day

Time is a key factor The more time between 1st and 2nd extinction sessions, the

more spontaneous recovery is observed

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Extinction & Spontaneous Recovery20


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Rapid Reacquisition

Conditioning phase extinction phase re-conditioning phase (i.e. reacquisition phase)

Rate of learning is faster the second time

Continues to get faster with repeated cycles

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Clinical Applications: Classical Conditioning

Pair unconditioned stimulus with undesirable behaviorto change the response

E.g., treating nocturnal enuresis with Mower & Mowers Bell &Pad method

Bell (US)Wake-up and tighten muscles to prevent urination (UR) Bodily sensations before urinating (CS) alarm bell (US)Wake-up

and tighten muscles to prevent urination (CR)

Use extinction to reduce unwanted response to

conditioned stimulus E.g., decreasing fear response to object of phobia with extinction

Repeatedly present the rat (CS) without the loud noise (US), untilthe CS no longer results in the CR

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Operant Conditioning


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Learning About the Consequences of Behavior

Operant conditioning = a procedure for studyinghow organisms learn about the consequences of theirown voluntary behavior

Realization that our ACTIONS (rather thanconditioned stimuli) lead to outcomes results inoperant conditioning

By operating on your environment, you canproduce a positive or negative consequence

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Edward Lee Thorndike25

Studied animal intelligence and learning

Placed a cat in the puzzle box. It wasencourage to escape to reach a scrap of fish

Thorndike timed how long it took to escape.The cats experimented with different waysto escape the puzzle box and eventuallywould stumble upon the lever which openedthe cage.

When the cat had escaped, it was put backin the box and timed as it tried to escape.

In successive trials, the cats would learnthat pressing the lever would have favorableconsequences, so they became increasinglyquick at pressing the lever


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Thorndikes Law of Effect

If a response to a particular situation is followed by asatisfying or pleasant consequence, it will bestrengthened.

If a response to a particular situation is followed byan unsatisfying or unpleasant consequence, it will be

weakened.

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B.F. Skinner

Original research Rats in Skinner boxes

Rats rewarded with food pellet forengaging in specific behaviors

Basic assumption Voluntary responses are strengthened

or weakened as a result of theirconsequences

Discriminative Stimulus: thestimulus situation that sets theoccasion for a response to befollowed by reinforcement orpunishment

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Learning the Association28


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Classical vs. Operant Conditioning29


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The Nature of Reinforcement

Reinforcement = consequences that INCREASEthe likelihood of the behavior occurring again

Positive reinforcement = a consequence that, whenpresentedafter a behavior, increases the likelihood of thatbehavior occurring again (e.g., getting an ice cream cone as areward for earning an A on a test)

Negative reinforcement = a consequence that, when removedafter a behavior, increases the likelihood of that behavioroccurring again (e.g., getting out of chores as a reward forearning an A on a test)

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The Nature of Punishment

Punishment = consequences that DECREASE thelikelihood of a behavior occurring again

Positive Punishment: a consequence that, when presentedafter a behavior, decreases the likelihood of that behavioroccurring again (e.g., getting a spanking after hitting your littlesister)

Negative Punishment: a consequences that, when removedafter a behavior, decreases the likelihood of that behavioroccurring again (e.g., getting time out from the fun activityafter hitting your little sister )

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Schedules of Reinforcement

Schedule of reinforcement = the rule used by theexperimenter to determine when particular responses

will be enforced (in order to teach the organism that

its behavior uniquely predicts the consequence) Continuous reinforcement schedule = consequence

delivered EVERY time behavior occurs

Partial Reinforcement schedule = consequence deliveredonly some of the time after the response has occurred

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Partial Reinforcement Schedules

Fixed ratio vs. Variable ratio: (deals with numberof responsesbefore consequence presented)

Fixed Ratio = the number of responses required for delivery ofthe consequence does not change (is fixed) across trials

Variable Ratio = the number of responses required for deliveryof the consequence changes (varies) across trials

Fixed interval vs. Variable interval: (deals withamount of time before consequence presented) Fixed interval = consequence delivered for the first response

that occurs following an unchanging (fixed) amount of time

Variable interval = the allotted time before a response willyield a consequence changes (varies) across trials

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Comparing Reinforcement Schedules34


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Variable Ratio Schedule Hardest to Extinguish35


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Effects on Behavior

Continuous reinforcement fastest acquisition ofresponse (learning); fastest extinction of response(unlearning)

Fixed ratio

fast acquisition; fast extinctionVariable ratio consistent acquisition; slowest

extinction

Fixed interval quickly learns to adapt behavior to

timing; fast extinctionVariable interval consistent acquisition; slower

extinction

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Operant Conditioning Concepts

Extinction:When a previously reinforced behaviordecreases in frequency, and eventually ceases altogether,because reinforcement is withheld

Spontaneous recovery:When an extinguished behavior

reappears without having been reinforced Generalization:When an individual learns to make a

particular response to a particular stimulus, and thenmakes the same response in a slightly different situation

Discrimination:When an individual learns to notice theunique aspects of seemingly similar situations, and thusdevelops different ways of responding

** Names are the same as classical conditioning, but concepts are slightly different


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Clinical Application: Operant Conditioning

Implement continuous reinforcement schedule (in order tofacilitate acquisition of desired behavior), then switch tovariable ratio schedule (in order to protect against extinction)

Parent Training teach parents how to use operant

principles to shape childrens behavior

E.g., children with disruptive behavior disorders

Praise/reward, Token economy, Time Out, Extinction,Punishment, Contingency management

Exposure / Response Prevention use negativereinforcement to change patients behavior

E.g., patients with OCD & other anxiety disorders

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Social Learning


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Learning From Others

Social (Observational) Learning: Occurs when anorganisms responding (learning) is influenced by theobservation of others, who are called models

Allows organisms to learn, without requiring their own trialand error experiences

Modeling occurs when an organism imitates the behavior

of others

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Albert Bandura

Conducted the Bobo Doll Experiment tostudy vicarious learning

Showed nursery school children a film thatportrayed a woman striking, punching, and

kicking a large, inflatable Bobo doll When later placed in a room full of toys

(including the Bobo doll), many childrenimitated the woman and violently attackedthe doll

This was more common when childrenviewed a film in which the woman waspraised (e.g., Youre the champion) forattacking Bobo

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The Model and the Imitators42


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Factors Affecting Social Learning

Models are more effective when they are: Attractive, honest, competent, and have elevated status

More likely to imitate models who are successful and/orrewarded for their behavior

Vicarious reinforcement and vicariouspunishment have effects on behavior that parallelThorndikes Law of Effect

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Clinical Applications: Social Learning

Skills Training Modeling adaptive behavior as a parent, therapist, etc.

E.g., teach shy children positive social skills

Vicarious exposure to adaptive behaviors Show videos or models engaging in desired behavior

E.g., show child with a dog phobia video of similar childrenplaying with dogs and having fun

Limiting exposure to maladaptive behaviors Prevent children from seeing others engaging in undesired

behavior

E.g., censoring TV shows, movies, video games

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