Basic Processes of LearningChapter 4

Principles of Learning

The environment is always fluctuating

LEARNING: the process or set of processes through which sensory experience at one time can affect an individual’s behavior at a future time Experience: any effects in the environment that are

mediated by the individual’s sensory systems

Classical Conditioning: Part I

Classical conditioning is a learning process that creates new reflexes REFLEX: a simple, relatively automatic, stimulus-response

sequence mediated by the nervous system

HABITUATION: the decline in the magnitude or likelihood of a reflexive response that occurs when the stimulus is repeated several times in succession

Tap on the

kneeStimulus

• Nerves

• Spinal Cord

Nervous system

Leg jerks

forward

Response

Pavlov’s Discovery

Ivan Pavlov (1849-1936)

Studied the reflexes involved in digestion

Could some other stimulus be triggering the salivating response in dogs?

Classical Conditioning

Extinction and Recovery from Extinction

• The gradual disappearance of a conditioned reflex that results when the CS occurs repeatedly without the UCS

EXTINCTION

• The return-due to the passage of time with no further testing or training-of a CR that had previously undergone extinction

SPONTANEOUS RECOVERY

Extinction and Spontaneous Recovery

Generalization and Discrimination

• The phenomenon by which a stimulus that resembles a CS will elicit the CR even though is has never been paired with the UCS

Generalization

• Procedure by which generalization between two stimuli is diminished or abolished by reinforcing the response to one stimulus and extinguishing the response to the other

Discrimination Training

Classical Conditioning and Behaviorism

BEHAVIORISM: (early 20th century) school of psychological thought that holds the proper subject of study is observable behavior, not the mind

Behavior should be studied through an environmental context, not an internal, individualistic context

John B. Watson

Poor Little Albert…

Stimulus-stimulus associatons

Pavlov’s Stimulus-Stimulus Theory

Watson’s Stimulus-Response Theory

CS• Bell

Mental representation of UCS• Food

CR• Salivation

UCS• Food

CR• Salivation

CS• Bell

CR• Salivation

Learned Expectancy Rescorla (1998): Classical conditioning is not a stupid process by which the

organism willy-nilly forms associations between any two stimuli that happen to co-occur. Rather, the organism is best seen as an information seeker using logical and perceptual relations among events, along with its own preconceptions, to form a sophisticated representation of its world.

Translation: The dog expects the food.

1. The CS must precede the UCS

• Classical conditioning does not occur if the CS and UCS occur simultaneously or the CS follows the UCS

2. The CS must signal heightened probability of occurrence of the UCS

• As the number of pairings increases, so does the strength of the association. Internal probability calculation?

3. Conditioning is ineffective when the animal already has a good predictor

• The Blocking Effect – new stimulus presented with CS does not become a new CS.

Conditioned Fear, Hunger and Sexual Arousal

FEAR• UCS: sudden, loud noises• Helps to avoid dangerous situations

HUNGER• UCS: smell, visual or auditory stimuli• The appetizer effect

SEXUAL AROUSAL• UCS: any kind of stimulus, really• Conditioning increases number of

offspring

Conditioned Drug Reactions

Drugs have two effects: the main effect and a compensatory effect that stabilizes the body

DRUG TOLERANCE: the phenomenon by which a drug produces successively smaller physiological and behavioral effects, at any given dose, if it is taken repeatedly

Overdosing

A Clockwork Orange

Operant Conditioning I

OPERANT CONDITIONING: a training or learning process by which the consequence of a behavior response affects the likelihood that the individual will produce the response again

Edward Thorndike

(1898)

Cats in the puzzle box

LAW OF EFFECT: Responses that produce a satisfying effect in a particular situation become more likely to occur again in that situation

Burrhus Frederic (“BF”) Skinner Researched and

popularized the theory of operant conditioning

Skinner box

REINFORCER: any stimulus change that occurs after a response and tends to increase the likelihood that the response will be repeated

Principles of Reinforcement

SHAPING: procedure in which successively closer approximations to the desired response are reinforced until the response finally occurs

EXTINCTION: the decline in response rate that results when an operant response is no longer followed by a reinforcer

How do you establish the first response?

Schedules of Partial Reinforcement (vs. continuous reinforcement)

Fixed-ratio schedule• A reinforcer occurs after every 9th response, where n is some whole number

greater than 1

Variable-ratio schedule• The number of responses required before reinforcement varies unpredictably

around some average

Fixed-interval schedule• A fixed period of time elapses between one reinforced response and the next

Variable-interval schedule• The period of time that must elapse before a response will be reinforced varies

unpredictably around some average

Reinforcement and Punishment

INCREASES TARGET BEHAVIOR

DECREASES TARGET BEHAVIOR

Positive Reinforcement(Lever Press Food pellet)

+ Add something good

Positive Punishment(Lever Press Shock)

+ Add something bad

Negative Reinforcement(Lever Press Shock off)

- Take away something bad

Negative Punishment(Lever Press removes food)

- Take away something good

Goal

Manip

ula

tion

Neg

ati

ve

(Rem

ovin

g s

om

eth

ing

)

Posit

ive

(In

trod

ucin

g s

om

eth

ing

)

The Big Bang Theory

https://www.youtube.com/watch?v=JA96Fba-WHk

Operant Conditioning II

Through discrimination training, an animal can be conditioned to make an operant response to a stimulus more specific than the entire inside of a Skinner Box. Discriminative stimulus

GENERALIZATION

The Overjustification Effect

OVERJUSTIFICATION EFFECT: the phenomenon in which a person performs a task for no reward becomes less likely to perform that task for no reward after a period of time during which he or she has been rewarded for performing it

Cognitive consequences of rewards

Facilitating Learning: PLAY

Exercise or activity for amusement or recreation; has no useful purpose

Allows the animal to practice their instincts or species-specific behavior

Groos’ Theory of Play1. the young play more than

adults2. Species that have the most to

learn play the most

Play in humans: a form of imitation

Facilitating Learning: EXPLORATION

EXPLORATION: the investigation of unknown regions

A more primitive form of learning

A balance of curiosity and fear

Exploration: Information Acquisition

Tolman and Honzik (1930): Rewards affect what animals do more than what they learn

LATENT LEARNING: learning that is not demonstrated in the subject’s behavior at the time that the learning occurs but can be inferred from its effect on the subject’s behavior at some later time

Facilitating Learning: OBSERVATION

OBSERVATIONAL LEARNING: learning by watching others

Stimulus enhancement: increase in the salience or attractiveness of the object that the observed individual is acting upon

Goal enhancement: an increased drive to obtain rewards similar to what the observed individual is receiving

Food-Aversion Learning What is safe to eat?

Most animals learn to avoid foods that have made them ill

Food aversion differs from classical conditioning because: A significant time delay CS must be a taste or smell

Food Preference Learning Animals must also learn to choose foods that satisfy a

nutritional requirement, can associate certain foods with improvement in health

Humans have a preference for high-calorie foods: (evolutionary advantageous)