stimulus preexposure Flashcards
1
Q
habituation
A
if you are presented are stim constantly you get used to it, changing the response you have
2
Q
within-compound association
A
presentation allows constituent elements of the stim to become associated
3
Q
what can these processes do
habituation, latent inhibition, perceptual learning
A
- recognition mem (for the stim)
- learning about the stim
- discrimination (from each other)
4
Q
theories of habituation
A
explained by general associative model (S-R theory and wagner’s theory)
5
Q
S-R theory and haituation
A
- link between S & R becomes less effective with use
- response recovers with time - spontaneous recovery
- stronger stim habituate more quickly
- a diff, arousing stim can produce dishabituation
- sometimes exposure can increase response sensitisation
6
Q
short term habituation
wagner
A
- after several trials: CS elements in A2 –> reduced response
- self-generated priming
- only applies if test occurs soon after expousre
7
Q
long term habituation
wagner
A
- context becomes associated with CS
- sends CS elements into A2 –> reduced response
- can occur over a much longer delay
as long as the object is presented in the same context, it will be expected there and its elements will enter A2
8
Q
davis (1970)
A
- short term habituation better with massed trials
- rats exposed close together 2s ISI or 16s ISI (same number of tones)
- theory - closer they are together, less time to decay and compete, less responding you are going to do
- long term habituation better with spaced trials when they were tested later
9
Q
wagner’s theory predicting UCR will return in a diff context
hall & honey (1989)
A
- tested by habituating stim (smell) in one context (light level), test same or diff context
- introducing a sound click or tone
- this acts as a novel experience - hadn’t experienced sound in diff context
- startle response to novel stim takes away from stim & food
- at first: puts them off food but over time they got used to it
- no difference between contexts
10
Q
potential mechanism for long term habituation
A
if elements of stim associate with each other during preexposure, they could prime each other into A2
11
Q
McLaren & Mackintosh (2000)
A
- unitisation
- arise from stim preexposure
- type of perceptual learning
- with long exposure associations form
- can affect discrimination
12
Q
habituation, associations & recognition memory
A
- habituation can be explained within our associative framework
- simply presenting an object can create a mem of it
- some of this can be explained by habituation & association formation
- why do we care? Because habituation & associations underlie mem, & mem can be impaired in some clinical conditions
- recog mem: prior experience of an item allows you to recog it in future - familiar & you can retrieve info about it
- recog is a component of episodic mem: presenting an item in a particular time & place can result in mem for that episode - what you experienced, when & where
- habituation & associative learning help explain these effects
13
Q
understanding amnesia
A
- declarative mem impairment is a key component of global human amnesia
- many claim it is independent of associative learning
14
Q
spontatneous object recognition (rats)
emnaceur & delacour (1988)
A
- aim - develop a mem task parallel to those used in humans for e.g. studying amnesia
- show a rodent an object it will explore for a whole then get bored
- can use as a measure of familiarity
- first present 2 identical versions of object A then give a choice between A and novel object B
- recog A = explore B as unfamiliar
15
Q
account 1 of spontaneous object recognition
A
- 1st presentation of object primes itself into A2
- so 2nd presentation produces less A1 activity - reduced response
16
Q
account 2 of spontaneous object recog
A
- although this effect workds with quite long (24hr) delays between preexposure and test
- so long-term habituation probably also plays a role
- context can predict familiar object, priming it into A2
- so when presented at test it produces less A1 activity because most of its element have been primed into A2
17
Q
account 3 of spontaneous object recog
A
elements of stim may associate with each other, priming each other into A2
18
Q
when memory
A
- can discriminate between 2 familiar items on basis of relative recency - if one has been seen more recently than the other
- rats & mice can do this
- relative recency task: look at longer ago one more
19
Q
where memory
A
- can also discriminate between 2 familiar items on basis of whether they are in right place or not - object in context task - a familiar item in unfamiliar place
- object in place task: sensitive to which corner’s which
20
Q
clayton & dickinson (1998)
episodic memory
A
- scrub jays like to bury worms, which rot, and peanuts, which don’t
- later they dig them up to eat
- allowed to cache both peanuts & worms in distinctive food trays
- group degrade - can learn that the worms go off
- group replenish cannot
- if get peanuts first which get left a long time and then worms left 4 hrs later they will pick worms
- if get worms first then peanuts they will choose peanuts as the worms would have gone off
21
Q
latent inhibition and SZ
A
- idea that delusions in SZ are due to aberrant learning about familiar everyday things that normally wouldn’t be learned about
- disruptive in SZ
22
Q
CS predictability
wagner’s account
A
- if CS pre-exposed, association forms between context & CS, so context puts most CS elements into A2
- thus few elements available for recruiting into A1 –> poor learning
- predicts that LI will be context specific
23
Q
CS predictive ability theories
A
- rescorla wagner: associability of a stim is a fixed property
- mackintosh suggested that associability may change with experience
- good predictors command attention
24
Q
pearce & hall (1980)
A
- bad predictors command att, good predictors don’t
- high attention –> good learning, high orientating
- in LI, CS a good predictor of nothing so associability low
- in normal conditioning, CS a good predictor of something so associability low
- in partial reinforcement, CS a poor predictor of something so associability high
- associability restored by a change in outcome
25
Q
swan & pearce (1988)
A
- manipulated predictive ability of a light to be higher in group same than diff
- more predictive = lower associability
- associaibility stim high then orientate to it (group diff)
- more conditioned responding to light in group diff
26
Q
low latent inhibition and SZ
A
- LI based on work with animals in which a stim is preexposed without consequence & then conditioned
- in humans - typical LI task uses masking procedure
27
Q
amphetamine model of SZ
A
- amphetamine taken to be an animal model of SZ & impaired LI a defining characteristic
- LI could be enhanced by drugs like haloperidol, which are now treatments for SZ
- consistent with amphetamine mimicking SZ in rat by affecting attention
28
Q
amphetamine & attention: a challenge
A
- some inconsistent findings
- most findings with shock experiments
- CR usually suppression of ongoing beh
- killcross et al. (1994): LI abolished by systemic amphetamine in aversive CER but not appetitive tasks - the CER effect could be abolished by reducing shock intensity
29
Q
le pelley et al. (2010)
A
- ppts split into high & low schizotypy
- unusual experiences difference between predictive & unpredictive cues only sig in low group
30
Q
perceptual learning
A
- lashley jumping stand
- gibson & gibson (1955): percepts change over time by progressive elaboration of qualities, features and dimanesions of variation
- assumed that effects of stim exposure are not associative - but no formal mechanism was proposed
- symonds & hall (1995): LI of common elements is mechanism of perceptual learning
31
Q
associaitve mechanisms that could produce perceptual learning
A
- LI of common elements
- mutual inhibition between unique elements
- unitisation (sticking units together)
