Classical Conditioning Flashcards
US
UR
CS
CR
an event that elicits a reflexive response.
response elicited by the US
stimulus that does not initially evoke the UR.
response elicited by the CS after learning.
Classic Demonstration:
Before Conditioning -
During Conditioning -
After Conditioning -
US (Food) > UR (Salivation)
NS (Tuning Fork) > No Conditioned Response (No Salivation)
NS (Tuning Fork) + US (Food) > UR (Salivation)
CS (Tuning Fork) > CR (Salivation)
CS must come before the US to create an association
Give US before the CS it will not be effective
forward conditioning
backward conditioning
Higher/Second Order Conditioning…
CS (electric can opener) + US (food) = UR (salivation)
Second-order stimulus (sneaky cabinet door) + CS (electric can opener) = CR (salivation)
Second-order stimulus (sneaky cabinet door) ) = CR (salivation)
e. g., person refuses to sit with friends in the backyard on a summer day. The sight of flowers greatly upsets her and she says, “With so many flowers there are probably bees.”
e. g., a bell is paired with food until the bell elicits salivation. If a light is then paired with the bell, then the light may come to elicit salivation as well.
after the original CS-US pairing, a second CS (CS2) is paired with a CS. Because of this pairing, CS2 is able to elicit the CR.
a bee (CS1) previously has stung (US) the person, and she has noticed that bees hover around flowers (CS2). The “phobic” fear of flowers occurs because of the correlation of bees (CS1) with flowers (CS2).
The bell is the CS1 and the food is the US. The light becomes the CS2 once it is paired with the CS1
Comparison of Classical Conditioning to Operant Conditioning
Classical Conditioning: food is delivered….
Operant Conditioning: rats behaviour
independently of rats behaviour, the rat does not have to do anything to get a response
causes food to appear, the rat has to do something to get the response/reinforcer
Examples of Classical Conditioning
(1) EYEBLINK CONDITIONING
US (puff of air to eye) + NS (light) > UR (blink)
CS (light) > CR (blink)
Examples of Classical Conditioning
(2) CONDITIONED EMOTIONAL RESPONSE or CONDITIONED SUPPRESSION
- Rats trained to press a lever for food,
- Next - during CC trials a CS (tone or light) is presented for say 1min followed by a brief shock (US),
- Obviously at the start of training rat ignores the CS,
- As pairing of CS (e.g. light) with shock proceeds rat will stop responding not just after delivery of shock but also while the light is on.
CS (tone) followed by an aversive US (electric shock).
After conditioning, CS becomes a CSave.
CSave elicits a CER (anxiety or fear)
e.g., rat trained to press a lever for food. After a stable rate of response is established, the CSave is introduced. When this occurs, the animal’s lever pressing is disrupted, by the CER elicited by the CSave.
A rat learns to press a lever throughoperant conditioning. Then, in trials, the rat is exposed to a CS (light/noise), followed by the US (electric shock). An association between the CS and US develops, and the rat slows or stops its lever pressing when the CS comes on. The rate of pressing during the CS measures the strength of classical conditioning; that is, the slower the rat presses, the stronger the association of the CS and the US.
ACQUISITION (learning)
There is a rapid increase in learning during early acquisition and then followed by an asymptote
greatest amount of learning occurs in earliest trials
Usually several pairings are needed between CS & US before CR fully develops
STIMULUS INTENSITY
intensity of the CS and US are important in determining the strength of the CR and the speed of acquisition
the stronger the US the faster the learning
STIMULUS NOVELTY
Latent inhibition refers to the observation that it takes longer for a familiar stimulus to become a CS than it does for a novel stimulus to become a CS, when the stimulus is subsequently paired with an effective US
If a CS is more novel, noticeable or salient it affects conditioning
By using latent inhibition, one is removing novelty of stimulus which then slows conditioning and the pps are less able to form an association with CS
Familiar stimulus: rate of acquisition is slower but still reaches the same point that the novel stimulus reaches
Highly familiar stimuli result in less rapid CC than if either the CS or US is novel.
Ss are exposed to the CS prior to pairing with the US - results in slower response acquisition.
TIMING
Forward conditioning
Backward conditioning
Tone > Food - US > CS
Food > Tone - CS > US
e.g., puff of air directed at a person’s eye followed by sound
EXTINCTION
presentation of CS…
stop the association between the CS and…
present CS in absence of
without the US
US.
US
e.g., CS (tone) > US (shock), CS (tone) > no shock
S-R model
NS becomes directly associated with…
The CS becomes directly associated with…
Therefore, the CS comes to elicit…
the UR and therefore comes to elicit same response as the US.
the UR
the same response as the UR.
S-S model
NS becomes directly associated with…
The CS becomes directly associated with…
Therefore, the CS comes to elicit…
the US & because of this association comes to elicit responses related to the US.
the US
a response that is related to the US
Relevance of CS to the US
Taste aversions are quickly learnt because they are so relevant to health
CS (food) relevant to US (food)
Findings from Garcia & Others
- easier to train rats to associate…
- easier to condition rats with…
- harder to condition pain and water
- therefore conditioning is easier…
new foods with nausea than associating flashing lights with nausea
pain and bright noisy stimuli
when two are relevant to one another
What is Learned in Classical Conditioning?
Slide 20
Slide 20
S-S Theory
- Two…
- Learned CS centre to…
- Innate US centre to…
S-R Theory
- One…
- CS centre to…
associations
US centre
response centre
association
response centre
Rescorla’s (1973) Experiment
Habituation to weaken…
Conditioned suppression procedure used (loud noise)
Habituation: Phase 1 (L > N), Phase 2 (Noise - Habituation)
Control: Phase 1 (L > N), Phase 2 (No stimuli)
Results:
if SR theory was correct…
if the SS theory was correct…
US-response link
habituation would have no effect – there would be a conditioned response.
weaken the connection between US and UR, it would eliminate conditioning, therefore habituation group would show reduced CR during test phase
IF CS is a substitute for US then expect…
HOWEVER
CR is often…
CR is often….
CR can be the….
CR to be effectively identical to UCR.
smaller than UCR
less complex
opposite of the UCR (i.e. COMPENSATORY CONDITIONED RESPONSES)
contiguity =
contingency =
one event reliably follows another
occurrence of one event depends on another.
A: Every time
wear funny shirt (CS) > laughed at (US) > sad (CR/UR)
high level of…
B: On 50% of occasions
wear funny shirt (CS) > laughed at (US) > sad (CR/UR)
lower level of…
Difference between A and B is change of…
‘B’ has lower…
Both ‘A’ & ‘B’ have high….
contiguity
contiguity
contiguity
CONTIGUITY between wearing T-shirt & being laughed at.
CONTINGENCY (being laughed at is contingent upon wearing the t-shirt )
C: On 50% of occasions
wear funny shirt (CS) > laughed at (US) > sad (CR/UR)
BUT on 50% of occasions
don’t wear funny shirt > laughed at (US) > sad (CR/UR)
Contiguity is the same in situation….
BUT…
‘B’ (low level)
NO CONTINGENCY in this situation
Contiguity reflects how often….
Contingency reflects how often….
US follows CS when the CS is presented
US occurs in absence of CS
Slide 6
Slide 6
Blocking Effect
Having already learned about one stimulus (formed a CS) you are less likely to..
learn about a new stimulus that occurs concurrently (i.e. a NS introduced concurrently).
The model expressed mathematically ….
delta Vi = Si (Vmax –Vi - Vsum)
delta V = i = S = V = Vmax = Vsum =
delta Vi = Si (Vmax – [Vi + Vsum])
change in associative value of CS from trial ‘x’ to ‘x+1’
a particular CS (e.g. a tone)
salience of CS
current associative strength of a particular CS
strength of US (= maximal strength possible for CS)
current total strength of other CS’s on trial ‘x‘
Learning = Intensity of CS x Surprisingness of US
How RW accounts for BLOCKING
If having got close to asymptote with CS ‘A’ (high Vi value near the ceiling level of 100) then adding in a novel CS ‘B’ (which currently has a V=0) will not improve the organism’s ability to predict the forthcoming US.
Because stimulus A is close to ceiling level = the difference between expectation and what we get is close to zero > therefore associative strength for B is very close to zero
Slide 13 and 14
Slide 13 and 14
Kamin: Blocking Effect
Experimental: (Phase 1) Light > Shock, (Phase 2) Light + Tone > Shock, (Test) Tone
Control: (Phase 1) X, (Phase 2) Light + Tone > Shock, (Test) Tone
Results?
Control - CR to tone (rat freezes)
Experimental - no CR to tone
Phase 1 blocked conditioning to the second stimulus
