Behaviour first 4 DO MORE ON CONDITIONING Flashcards
Classical conditioning
predicting what’s going to happen stimulus predicts stimulus whatever animal does
learned CR involuntary – not rational or goal directed - reflects what the animal knows will happen
Instrumental conditioning
controlling what’s going to happen. response only predicts a stimulus if animal responds
response voluntary – rational, goal directed. reflects what animal wants to happen
Omission training
- Keylight CS predicts food but conditioned peck cancels food
Eventually, the bird learned to stop pecking, but note that orientation toward the key continues
evaluative conditioning
- motivational properties of US transfer to CS
- e.g. an unconditioned response for nice food is liking
this transfers to the keylight – also likes the keylight.. will approach the keylight, work to obtain it
Second order conditioning
- Can build long chains of associations
Box -> purple wrapper -> chocolate & toffee -> sweet taste
CS3 -> CS2 -> CS1 -> US - our world is full of things that were once neutral, but we learned to value positively or negatively through associations
sensory preconditioning.
- You have never tried chocolate. But you learned that the purple sweets come in the Quality Street box (even though you never ate them).
- Then one day a friend convinces you to try one. It’s the best thing ever! Now you start to like the purple wrapping and the Quality Street box.
you associated sweets and box, even though neither had value
Conditioned Inhibition
- A conditioned inhibitor signals the absence of the US
- tone -> food tone+light -> no food
- light signals the absence of expected food
tone EXCITES mental representation of food, but light INHIBITS it
Kamin (1969) Blocking
- Same number of light à shock pairings in both groups
- In Group 1 light conditioned with a pretrained noise N
- In Group 2 light conditioned with a novel noise N
- In Group 1 shock not surprising – predicted by pretrained noise.
- In Group 2 shock not predicted, and is surprising.
- Less learning in Group 1, where shock not surprising
- The pretrained noise blocked learning about the light in Group 1
This important observation, that pairings only produce learning when the US is surprising
Rescorla and Wagner (1972) equation
how much association strength increases on each trial (i.e. CS —> US pairing)
- ∆V = ab ( lambhda - EV )
- All the symbols have a psychological meaning
- V is associative strength between CS & US
- ∆V is change in V after each pairing
after one trial V low
a few trials V medium
lots of trials V high
what is a in the equation association strength
a refers to the salience of CS - its intrinsic perceptual intensity
brighter light = more salient a
what is B in the equation for association strength
B refers to salience of US - its intrinsic perceptual intensity
what is lander in the equation for association strength
refers to the size of the US - another physical property
what is EV in the equation for association strength
how much US is predicted
the sum of the associative strengths Vs of everything else that is present on that trial
what is (lander - EV) in the equation for association strength
how surprising the US is
learning stops when… (equation)
EV = lander
Mackintosh 1976
Conditioning two CSs at once
Equal numbers of pairings of light with shock but in overshadowing groups noise presented: quiet n or loud N
Difference between OC and CC
The first event in the association depends on the learner
Making the response is under their control
Law of Effect (Thorndike)
“Of several responses made to the same situation, those which are accompanied or closely followed by satisfaction to the animal will.. be more likely to recur; those which are accompanied or closely followed by discomfort to the animal will… be less likely to occur. The greater the satisfaction or discomfort, the greater the strengthening or weakening of the bond.”
in some ways Thorndike was wrong
- Once the association was formed, the S always elicits the R – but the animal does not know why – it is not responding for a goal.
- If the child got bored of being praised, it would still tidy up
- If rat was full it would still respond
Difference between Thorndike and modern view
Thorndike - US not incorporated in learning, respond because S is there value of US is irrelevant.
A habit
Modern view - US incorporated in learning, respond to get US because it has value
A goal-directed action
Punishment?
- What’s nasty? (punishment)
- getting something nasty (shock) positive
- OR omitting something nice (cancel food) negative
- a response followed by either of these will go DOWN
Reinforcement?
- What’s nice? (reinforcement)
- getting something nice (food) positive
- OR omitting something nasty (cancel shock) negative
a response followed by either of these will go UP
Operant techniques: Escape
- Responses rewarded by removing aversive USs e.g. shock after they’ve begun
- Escape an aversive US e.g. shock after its started
- Escape response rewarded by removing shock
Operant techniques: Avoidance
- Avoidance - avoid an aversive US altogether
- Responses rewarded by removing aversive USs e.g. shock before they’ve begun
- Must respond before US happens
Passive avoidance
rat must stay where it is to avoid shock
Active avoidance
rat must move to other
Signalled avoidance
explicit CS signal for shock e.g. a buzzer
- whenever he hears buzzer he must move to other chamber to avoid shock
Sidman avoidance
inescapable aversive stimuli are presented at fixed intervals (shock–shock intervals) in the absence of a specified response. If the response is made, the aversive stimulus is postponed by a fixed amount of time
- e.g. shock every 5 seconds BUT if animal responds, shock is delayed a further 10s
- If animal responds at a steady rate shock is postponed indefinitely
Kamin, 1956
Rat in chamber. Buzzer comes on, followed by shock. Rat must now respond to avoid the shock
- Animals learn most when buzzer terminated and shock cancelled
- Learn least when responses ineffective – (must be operant conditioning)
- Learn something even when they only terminate the warning CS, not the shock!
- both types of event play a role
Why are you making the avoidance response?
- buzzer –> shock buzzer + avoidance response —> no shock
- response cancels the expected shock
- response —> omission of expected shock
- omission of shock is a nice thing – avoidance response is being rewarded
Soltysik et al. 1983
Cats. CSs signal mild shock.
- CRs e.g. paw flexion, respiration and heart rat change
- Stage 1
* Tone à shock Click à shock
* Tone+lightà nothing Click+lightà Nothing
- tone and clicker predict shock; light signals absence of expected shock
- Light is a conditioned inhibitor
ratio schedule
reward a fixed number of responses
this can be fixed (e.g. every 10 responses exactly)
- or variable (every 10 on average, but sometimes more sometimes less)
- this is what supports people’s gambling behaviour!
interval schedule
can be fixed (e.g. exactly every minute)
reward a child for tidying their room by a trip to the chippy, but only on Fridays. Child tends to tidy his room on Thursday night! Fixed interval; responding occurs near the time of reinforcement
- or variable (e.g. once per minute on average, but sometimes less sometimes more)
- e.g. reward a child for tidying their room by a trip to the chippy, but randomly throughout the week. Child will keep his room tidy all week; low but steady rates of responding and is often used in experiments
what is an uncondtioned stimulus (US/UCS)?
a stimuli that can automatically elicit unlearned unconditioned responses because of a pre-existing, unlearned association
give an example of an unconditioned stimulus?
food, which naturally produces salivation - does not need to be learned
what types of unconditioned responses (UR/UCR) can there be?
overt muscular responses (approach/avoid)
- internal (like/dislike response)
in classical conditioning, an association forms between….
a conditioned stimulus and an unconditioned stimulus
in instrumental conditioning, an association forms between…
a response and a stimulus
when a cough is paired with a tickle, what is the unconditioned stimulus to produce a giggle?
the tickle, because it is already linked to a unconditioned response (giggle)
does a conditioned stimulus indirectly or directly elicit the conditioned response?
indirectly
is classical conditioning stimulus-response learning?
no - because conditioned response not directly associated to the conditioned stimulus
if classical conditioning were a direct link between stimulus (cough) and response (giggle) link, what would happen when the child no longer wanted to be tickled?
they would still giggle, regardless of the tickle no longer being rewarding (this is not true)
what did Thorndike argue about S-R learning?
to form an S-R association, you need a reinforcer to stamp it in - so thought all learning requires a response and a reinforcer
what did Hull think it was important only to study?
observable things - so learning had to be visible between visible S and visible R
are Hull and Thorndike wrong about S-R learning?
yes - learning can happen without a response or reinforcer
what is shaping?
instrumental conditioning procedure where reinforcers guide behavior toward closer and closer approximations of the desired behavior (placing pellets on a lever to get a rat to press it for food)
what is autoshaping?
classical conditioning procedure where conditioned response is a modified instinctive response to certain stimuli (pair light with food, CR is to peck = pigeon shapes itself in sense that pecking happens spontaneously)
what does stimulus substitution explain?
form of conditioned response - it’s like the unconditioned response (pigeons peck grain, when light paired with grain, they peck light)
what is evaluative conditioning?
changes in the liking of a conditioned stimulus that result from pairing that stimulus with other positive or negative unconditioned stimuli
what is extinction?
when you take away the UCS (food, shock), the conditioned response slowly dissipates
describe spontaneous recovery following conditioned inhibition?
inhibitory associated more disrupted by passage of time, so excitatory association can show and CR returns but never as strong as it originally was
how can inhibitors have motivational value?
if you are hungry and expected food and didn’t get it, that makes you sad
but if you expected something bad that didn’t happen, that will make you happy
motivational states can be positive or negative
how does instrumental conditioning differ from classical conditioning?
response (tidying up) is paired with unconditioned stimulus (praise), not conditioned stimulus
what does a discriminative stimulus mean?
when the response is only followed by the unconditioned stimulus when another stimulus is present: parent (Sd) must be present for child to receive praise (UCS) from tidying up (R)
what did Thorndike assume would happen once the association between stimulus and response was formed?
he stimulus would always elicit the response, but the animal does not know why - it is not responding for a goal
if child got bored of being praised, it would still tidy up
in Kamin’s (1956) study into what maintains an avoidance response, describe the experimental set up?
- rat in chamber
- buzzer comes on
- followed by shock
- rat must now respond to avoid shock
what is continuous reinforcement?
giving a reward for every response
what is partial reinforcement?
giving a reward for only some responses
