learning

distribution of learning

rats, pigeons, fish, octopus, ants, snails, single celled organisms, plants

human learning

we can learn in our sleep

• in sleep, presented pleasant or unpleasant smells - sniffing inc during REM and nREM sleep during pleasant vs unpleasant

• changed behaviour to a high or low tone associated with smells - happened in waking hours too

definition of learning

no generally-accepted definition but

• a relatively permanent change in behaviour as a consequence of experience

reflexes

• fast and automatic

• dont need brain - can use spinal cord

• eg reflex arc

predictive relationships

many organisms live in environments that have predictive relationships between events - however predictive relationships may change (eg finding food in summer vs winter)

• to survive animals must modify their behaviour as a consequence of their experience with the environment

• learning is not just about responding to stimuli, its about predicting stimuli

habituation

the relatively persistent waning of a response as a result of repeated stimulation which is not followed by any kind of reinforcement

whitlow

vasoconstriction (blood volume) in rabbit ears in response to 1s 530 or 4000 hz tones

• vasoconstriction in ears inc with stimulus, then when presented again the vasoconstriction was less, compared to a different stimulus - this diminished 150 post seconds

• short term habituation effect

cross - music

neonatal rats split into a Mozart or Schoenberg group - 12 hour exposure per day to vocal or non-vocal selections for 52 days

• had choice of entering a compartment of a box playing novel Mozart or shoenbergs music (15 days after exposure phase)

• all Mozart and all shoenbergs still showed a significant amount going into the other music - showing habituation from exposure

domjam - water

water-deprived rats, into group S and group W

• S = 30 min access to sweetened water then 30 mins water per day

• W = 30 min just water per day

• measured consumption each day across 20 days

• rats are cautious about novel flavours (sensible, reduces chance of poisoning)

• with experience diet can be widened through habituation

classical conditioning - pavlov

learning to associate and anticipate events

unconditioned stimulus US

biologically significant stimulus eg food/pain

Unconditioned response UR

response evoked by US

conditioned stimulus CS

previous neutral stimulus (eg bell, light) that acquires a respose by being paired with the US

conditioned response CR

response evoked by the CS

classical conditioning as learning

behaviour of pavlovs dogs changed in a relatively permanent fashion (acquired a CR) as a consequence of experience (pairing CS with US)

• can describe different learning experiments with the same language

appetitive conditioning

US is pleasant

aversive conditioning

US is unpleasant

Martin and levey - human eye conditioning

when shown red block = nothing , when shown blue block = cornea air puff

• CR = blinking

• at first, little evidence of blinking during lights - then blinking elicited by CD that predicted the air puff (US)

• functional - eyelid responses anticipate irritations and protects eye

trace conditioning with X rays as an aversive stimulus

experimental group training

• rats allowed ro drink sucrose solution (CS) then given 1 dose of X radiation to induce nausea (US)

• interval between CS and US varied between groups

control group training

• same but X rays not delivered when button was pressed

choice between sucrose solution and water

• control - liked sucrose

• experimental - more time passed = more likely to have sucrose (6 hours still a conditioned response)

special form of conditioning?

conditioning when there is a substantial interval between CS and US, and when there was one CS-US pairing

• maybe being able to to acquire an aversion quickly and over a long interval is functional, and maybe an adaptive specialisation

left vs right side of space

people put good things in their dominant side of space eg when ptps given cartoon animals described as good or bad, left handed people put the good one in the left box vice versa

• people associate good things more strongly with the side of space they can interact with more fluently

• peoples reach positive things with dominant hand, so it then is associated with positive things

• presidential candidates use their dominant hand in debates to show positive things

3 features of classical conditioning

acquisition

extinction

spontaneous recovery

acquisition

the initial increase in responding to a CS when its pared with a US

extinction

the weakening of conditioned responding if the CS is subsequently presented without the US

spontaneous recovery

an increase in an extinguished conditioned response due to the passage of time

example of spontaneous recovery in rats

rats in a conditioning container, pellets = UCS

1. during conditioning, learning took place over the first 6 days

2. during extinction, they slowly recovered each day throughout the 9 trials

exposure therapy

if a stimulus has a maladaptive response, you can break the connection between the stimulus and the behaviour through extinction - repeat several times

generalisation

4 groups of pigeons had different wl of light paired with food - 530, 550, 580, 600nm

• conditioned response: pecking key light

• pigeons still relatively successful in pecking when WLs were similar - generalisation - then discrimination the further away it gets

Blough (1975)

neurons conditioned to certain stimulus, the further along the wavelength you get, some still activated but som are not

who did instrumental conditioning

thorndike

instrumental conditioning

contingent upon behaviour of the animal

the law of effect

of several responses made to the same situation, accompanied or closely followed by satisfaction to the animal will be more firmly connected to the situation

S-R

• associations are formed between a stimulus and response

• reinforcement merely strengthens S-R association

thorndike

cats would take 60-120s to escape, then 20s after a dozen trials

continuous reinforcement

reward delivered every time animal makes a response

ratio/fixed schedule

reward is delivered after a certain number of responses are made

• fixed vs variable (changes after each trial)

interval schedule

reward delivered after first response is made after a certain interval is passed

• foxed vs variable

instrumental conditioning

• widespread - all manner of species can be trained to jump or swim through loops for reward

• sometimes hard to get started if they dont respond initially - use shaping - successive approximations until desired response

why do we have a conservative approach to learning?

physiology - brains are made of connections between neurons

ockhams razor - simplest explanation is best

items of association for thorndike

only thing rats would be aware of is if they see a lever, to press it (according to law of effect) - has no knowledge that its action is followed by food

Adams

stage 1: lever press → sugar pellet

stage 2: sugar pellet → illness (or control - sugar pellet or illness separated by a lot of time)

• 100 presses: exp group were more reluctant to press lever - contradicts thorndike (shouldn’t know consequence of behaviour is illness)

• 500 presses: more likely to press lever than control - more conditioning - devaluation more successful - agrees with thorndike

what does Adams experiment imply

• something not present is influencing behaviour

• conditioning results in a representation or image being activated

• can a representation/ an image of something not present also be conditioned

holland

stage 1: tone = food 1 // light = food 2

stage 2: tone → illness (food 1)

avoided food 1 - animals can learn to associate things that are there in the world with things in their mind