Lecture 7: Nurture

Non-associative learning

procedures when only a single event of stimulus is presented without any reward or punishment; can be presented in two ways:

• Habituation

• Sensitization

Habituation

Respond less strongly over time to repeated stimuli

Sensitization

Respond more strongly over time to repeated stimuli

Imprinting

Often within hours or days of birth or hatching, and creates an enduring behaviour that is often directed toward a specific individual

Classical Conditioning- British Associationists

believed that all knowledge is virtually acquired by connecting one stimulus with another

Classical Conditioning: Ivan Pavlov

studied digestion in dogs; noted associative conditioning between neutral stimuli and meat powder (Pavlovian Conditioning)

Pavlov described classical conditioning involving

• UCS

• UCR

• NS

• CS

• CR

UCS

Unconditioned stimulus- biologically significant stimulus that produdces automatic response

UCR

Unconditioned response- automatic response to a UCS that occurs w/o learning

NS

neutral stimulus- stimulus that produces no response

CS

conditioned stimulus- initially neutral stimulus, becomes associated w/ UCS through conditioning

CR

conditioned response- learned response

Classical Conditioning Steps

1. Neutral Stimulus (NS): does not elicit a particular response

2. Pair NS repeatedly w/ UCS, which elicits a UCR

3. Eventually NS becomes UCR

Aversive conditioning

Classical conditioning to an unpleasant UCS

Acquisition

Learning phase during which CR is established

Extinction

Gradual decrease and elimination of the CR when the CS is presented repeatedly w/o the UCS (unwritten, not forgotten)

Classical conditioning principals

1. Spontaneous recovery

2. renewal

3. phobias

4. stimulus generalization

5. stimulus discrimination

Spontaneous recovery

Sudden reemergence of an extinguished CR after a delay

Renewal

Recovery of the conditioned response when the organism

Phobia

intense and irrational fears

• some acquired via classical conditioning

• subject to spontaneous recovery and renewal

Stimulus generalization

elicitation of a CR to stimuli that are highly similar to, but not identical to, the CS

• generalization gradient

Generalization gradient

the more similar to the original CS the new S is, the stronger the CR will be

Stimulus discrimination

opposite of stimulus generalization; occurs when we exhibit a CR to certain CSs, but not others

Higher-order conditioning

process by which organisms develop classically conditioned responses to CSs associated w/original CS

Applications of Classical Conditioning

1. advertising

2. Acquisition of fears: Little Albert

3. Drug tolerance/habituation

4. Acquisition of fetishes

5. disgust reactions and taste aversions

6. immune and endocrine system

Advertising

Pairing positive USs w/product CSs

• Latent inhibition: when we’ve experienced a CS alone many times, it’s difficult to classically condition it to another stimulus

Acquisition of Fears: Little Albert

•Watson & Rayner (1920) sought to disprove the Freudian view of phobia, reflecting deep-seated unconscious conflict

•They recruited an infant, Albert, and paired a white rat (CS) with a loud clanging metal noise (UCS)

•Five days later, Albert exhibited fear of the rat, and similar stimuli, including a rabbit, dog, furry coat, and Santa Claus mask (generalization of phobia)

•Led to the conditioning model of phobias

D

Drug tolerance/habituation

Conditioned compensatory response: a conditioned response (cue-dependent tolerance to drugs)

Acquisition of fetishes

Fetishism: experiencing sexual attraction to non-living things

1.  Domjan and colleagues classically conditioned fetishes in Japanese quail

2.  Classical conditioning may contribute to the development of fetishes

Disgust reactions and taste aversions

 in most cases, a product of classical conditioning because CSs associated with disgusting UCSs come to elicit disgust themselves

immune and endocrine systems

•Studies reveal that classical conditioning can produce immunosuppression

•A decrease in the production of antibodies, which can lower a person’s ability to fight disease

Operant conditioning

acquiring behaviour as a result of the outcome or consequence of those behaviours

• learning that is controlled by the consequences of the organism’s behaviour

Differences between operant and classical conditioning

Law of effect

• principle asserting if a stimulus followed by a behaviour results in a reward, the stimulus is more likely to elicit the behaviour in the future

B.F. Skinner and Reinforcement

Developed a highly efficient conditioning chamber (Skinner box) that allows fror conditioning and automated behaviour

Reinforcement

outcome or consequence that strengthens the probability of a response

can be positive or negative

• Positive: pleasant stimulus given to strengthen the probability of a response

• Negative: unpleasant stimulus removed to strengthen the probability of a response

Punishment

outcome or consequence that weakens the probability of a response

must be consistent, immediate and with other behavioural reinforcement

can be positive or negative

• Positive: unpleasant stimulus given to weaken the probability of a response

• Negative: pleasant stimulus removed to weaken the probability of a response

Discriminative stimulus (S^d)

stimulus associated with the presence of reinforcement

Partial vs. continuous reinforcement

behaviours that we reinforce only occasionally are more resistant to extinction than those we reinforce continuously

Principles of Reinforcement

• Schedules of reinforcement

• Patterns of reinforcing a behaviour

Schedules of reinforcement

vary along two dimensions

1. consistency of administering reinforcement (fixed or variable)

2. the basis of administering reinforcement (ratio or interval)

patterns of reinforcing a behaviour

• Fixed ratio: R after regular number of responses

• variable ratio: R after specific number of responses, on average

• fixed interval: R after specific amount of time

• variable interval: R after average time interval

Applications of Operant Conditioning

• Shaping by successive reinforcement

• chaining

• Premack principle

• superstitious behaviour

• token economies

Shaping by successive reinforcement

reinforcing behaviours that aren’t quite the target behaviour but that are progressively closer versions of it

Chaining

linking a number of interrelated behaviours to form a longer series

Premack principle

a less frequently performed behaviour can be increased by reinforcing it with a more frequent behaviour

Superstitious behaviour

behaviour linked to reinforcement by sheer coincidence

Token economies

mental hospital staff can reinforce patients who behvae in a desired fashion using tokens, chips, points, or other secondary reinforcerss

Secondary reinforcer

neutral objects that patients can trade later on

Primary reinforcers

items or outcomes that are naturally pleasurable; i.e., a favourite food or drink

Applied behaviour analysis (ABA)

a set of techniques, based on operant conditioning principles, that relies on the careful measurement of behaviour before and after implementing interventions

Two process theory

  The two-process theory explains fear acquisition:

1.  People acquire phobias using classical conditioning

2.  Once phobic, people begin avoiding their feared stimulus and leading them to experience a reduction in anxiety, which negatively reinforces their fear

Stimulus-Organism-Response Theorists

focus on how the organism interprets the stimulus before generating a response

Radical behaviourists

focus on how thinking, emotion, and observable behaviour are all dictated by operant and classical conditioning

• viewed cognitive psychology as a pseudoscience

Latent learning

learning that isn’t directly observable; learning many things without showing them

• Tolman

Observational learning

Learning by watching others without instruction or reinforcement

Insight learning

when subject suddenly “get” the solution to a problem, and from there on get it right almost every time

Conditioned taste aversion

classical conditioning can lead us to develop avoidance reactions to the taste of food

Preparedness (regarding phobias)

suggests that we’re evolutionarily predisposed to fear certain stimuli more than others

Instinctive drift

the tendency for animals to return to innate behaviours following repeated reinforcement