ITP Topic 5 Learning

Learning

is defined as a relatively enduring change in behaviour resulting from experience. it occurs when an animal benefits from experience to better adapt to its environment

Nonassociative learning

A change in behaviour or response after repeated exposure to a single stimulus or event.

Non-associative = ONE stimulus, response changes.

Associative learning

Learning that two stimuli or events are related to each other.

Social learning

acquiring or changing a behaviour after verbal instruction or observing others

Nonassociative learning

Habituation and dehabituation

a decrease in behavioural response after repeated exposure to a non-threatening stimulus. it allows us to ignore meaningless events

dishabituation: an increase in a response because of a change in something familiar

Nonassociative learning

Sensitisation

an increase in behavioural response after exposure to a stimulus, typically one that is threatening or painful

What is the neural basis of habituation and sensitization?

• Habituation: Results from a decrease in neurotransmitter release from presynaptic neurons, producing a weaker response.

• Sensitization: Results from an increase in neurotransmitter release from presynaptic neurons, producing a stronger response.

Associative learning

classical (pavlovian) conditioning

a form of learning in which neutral stimulus comes to elicit a response when it is associated with a stimulus that already produces that response

4 core components of classical conditioning

• Unconditioned stimulus (US): a stimulus that naturally elicits a response without prior learning (eg. food)

• Unconditioned response (UR): an unlearned, automatic behaviour (e.g. salivation at food)

• Conditioned stimulus (CS): a stimulus that elicits a response only after learning (e.g. a metronome)

• Conditioned response (CR): the learned response to a conditioned stimulus (e.g. salivation at the metronome)

The CR is typically weaker than the UR

Classical conditioning

Unconditioned stimulus (US)

a stimulus that naturally elicits a response without prior learning (eg. food)

Classical conditioning

Unconditioned response (UR)

an unlearned, automatic behaviour (e.g. salivation at food)

Classical conditioning

Conditioned stimulus (CS)

a stimulus that elicits a response only after learning (e.g. a metronome)

Classical conditioning

Conditioned response (CR)

the learned response to a conditioned stimulus (e.g. salivation at the metronome)

Key principles of classical conditioning

• acquisition

• extinction

• spontaneous recovery

• stimulus generalisation

• stimulus discrimination

• second-order conditioning

Key principles of classical conditioning

Acquisition

the gradual formation of an association between the CS and the US.Timing is critical; the CS should ideally begin just before the US

Key principles of classical conditioning

Extinction

the weakening of the CR when the CS is repeatedly presented without the US

Key principles of classical conditioning

Spontaneous recovery

the temporary re-emergence of an extinguished CR after a rest period. this indicates that extinction overwrites rather than eliminates the original association

Key principles of classical conditioning

Stimulus generalisation

learning that occurs when stimuli thats similar, but not identical, to the CS produce the CR (e.g. fearing all three-leafed plants after a bad experience with poison ivy)

Key principles of classical conditioning

Stimulus discrimination

learning to differentiate between two similar stimuli if only one is consistently associated with the US

Key principles of classical conditioning

Second-order conditioning

when a CS (eg. money) is associated with other neutral stimuli, allowing those new stimuli to produce a CR without ever being paired with the original US

The cognitive model: Bescorla-Wagner

this model suggests that the strength of conditioning is determined by how unexpected, known as prediction error

Prediction error

Positive prediction error

something unexpected or stronger than expected happens, strengthening the CS-US association

Prediction error

Negative prediction error

an expected event does not happen, weakening the CS-US association

What is biological preparedness in classical conditioning?

An innate tendency to form some associations more easily than others because they are biologically relevant.

Example: Rats easily associate taste with illness and light/sound with shock, but have difficulty learning the reverse associations.

What is contiguity in classical conditioning?

The CS and US must occur close together in time, with conditioning usually strongest when the CS occurs shortly before the US.

What is contingency in classical conditioning?

The CS must predict the likelihood of the US. Conditioning occurs when the US is more likely to occur when the CS is present.

Which timing of the CS and US produces the strongest classical conditioning?

Forward pairing: the CS occurs shortly before the US.

What is a compensatory conditioned response?

A CR that opposes the effect of the US, helping the body prepare for the expected stimulus.

Example: Environmental cues associated with repeated drug use can trigger bodily responses that counteract the drug's effects, contributing to tolerance.

Operant (instrumental) conditioning

it is the process where the consequences of an action determine the likelihood that the behaviour will be repeated. Unlike classical conditioning, which is passive, operant conditioning requires a voluntary action

Foundations of operant theory

Law of effect (Thorndike)

behaviour leading to a “satisfying state of affairs” are likely to be repeated; those leading to an “annoying state of affairs” are less likely to occur

Foundations of operant theory

Behaviourism (Watson skinner)

An approach to psychology that focuses on observable behaviour and how it is learned or shaped by the environment, rather than on thoughts and feelings that cannot be directly observed.

Operant conditioning

Positive reinforcement

add something pleasant→ behavior increases.

Operant conditioning

Negative reinforcement

remove something unpleasant → behavior increases.

Operant conditioning

Positive punishment

add something unpleasant→ behavior decreases.

Operant conditioning

Negative punishment

remove something pleasant→ behavior decreases

Operant conditioning

Shaping

reinforcing “successive approximations” of a desired behaviour to teach complex actions

example: training a dog to roll over

Operant conditioning

Primary reinforcers

satisfy biological needs (food, water)

Operant conditioning

secondary reinforcers

established through classical conditioning (money, grades, compliments)

Operant conditioning

Premack principle

using a more-valued activity to reinforce a less-valued one (e.g. eat your spinach, then you get dessert)

Operant conditioning

Temporal discounting

the tendency for the value of a reward to diminish as the delay in receiving it increases

Schedules of reinforcement

• Fixed interval (FI)

• Variable interval (VI)

• Fixed ratio (FR)

• Variable ratio (VR)

Schedules of reinforcement: description and response pattern

Fixed Interval (FI)

• reinforcement after a predictable amount of time

• scalloping: increased activity just before the interval ends

Schedules of reinforcement: description and response pattern

Variable Interval (VI)

• reinforcement after an unpredictable amount of time

• Steady, frequent checking

Schedules of reinforcement: description and response pattern

Fixed Ratio (FR)

• reinforcement after a predictable number of responses

• High rates of responding (e.g. free pizza after 10 purchases)

Schedules of reinforcement: description and response pattern

Variable Ratio (VR)

• reinforcement after an unexpected number of responses

• high, persistent rates of responding; most resistant to extinction

Operant conditioning

Partial-reinforcement extinction effect

behaviours learned under partial (intermittent) reinforcement are more persistent and resistant to extinction than those learned under continuous reinforcement

Biological and neural influences on learning

while timing and intensity are vital, learning is not infinitely flexible (challenging the principle of equipotentiality).

Biology and evolution impose significant constraints.

Biological constraints

Conditioned taste aversion

an evolutionary adaptation where animals quickly associate a specific taste with illness, even if the illness occurs hours later

Biological constraints

Biological preparedness

animals are genetically programmed to fear specific dangerous objects (snakes, fire, heights) more easily than non-threatening ones (flowers, shoes)

Biological constraints

Innate behaviours

animals struggle to learn behaviours that run counter to their evolutionary adaptations (e.g. a raccoons hardwired rubbing instinct interfering with a task)

The role of dopamine

dopamine release in the nucleus accumbent (part of the basal ganglia) sets the value of rewards

The role of dopamine

Deprivation

Hunger or thirst increases dopamine release, making reward more potent

The role of dopamine

Wanting vs liking

dopamine is primarily linked to wanting (the desire/craving to consume), while other neurotransmitters like endogenous opiates are linked to liking (the subjective sense of pleasure)

Observational learning

Modelling

Learning a behaviour by observing and imitating another person’s behaviour.

Observational learning

Vicarious learning

Learning by observing the consequences of someone else’s behaviour.