Classical Conditioning

Since UR and CR produce the same effect, are they the same thing?

• they are NOT the same thing

• UR = natural, unlearned behavior (instinct)

• CR = learned, triggered behavior

Ways to measure the CR

• amplitude

• probability

• latency

amplitude

strength of the conditioned response

probability

how often the conditioned response occurs

latency

the time for the CR to occur

is classical conditioning voluntary or involuntary?

involuntary

acquisition

• learning; period of time when pairing the CS with US

• more reinforcement or trials makes the CR stronger

extinction

• if you do not provide the CS with the US, the strength of the CR decreases and goes away

• due to buildup of inhibition (learned idea that bell leads to no food inhibits the idea that the bell leads to food)

spontaneous recovery

• after 24 hours, the CR is recovered without any further training (spontaneous)

• the CR not as strong as previous day

• extinction happens faster from now on

fully extinguished response

the CR no longer happens after a certain amount of time

rapid reacquisition

learning conditioned response even faster after the first time

What do we learn from spontaneous learning?

• learning never truly goes away

  • even when extinction happens, dog has spontaneous recovery to rely on

  • even when spontaneous recovery goes away, re-learning happens quickly

Why does learning never truly go away?

• because excitatory association is being built up (becomes permanent)

• every trial, association becomes stronger

• when the maximum is reach, the acquisition if complete

inhibitory association

• learned during extinction

• tells the dog that the bell does not mean food

• gets stronger with every extinction trial with no US (food)

• as it gets stronger, it cancels out the excitation

• NOT permanent

What is the level or strength of the CR equal to?

excitation - inhibition

What happens when inhibition = excitation?

extinction has occured

What happens to inhibitory association during a rest period?

• is dissipates, but doesn’t go away completely

• a little remains and becomes permanent

  • so, when extinction trials begin again, inhibition builds up but with a head start

• extinction becomes faster because of this

What occurs after several (8-10) days of extinction trials

• all of the inhibitory associations are left behind (permanent)

• both cancel out, so there is no spontaneous recovery

What cannot be explained by the above model?

• rapid reacquisition

contiguity

• closeness in time in between the CS and the US

• too far a part in time will produce more inhibitory association

optimal time interval

• the best time between presenting the CS and the US to get the strongest CR

• can differ depending on the experiment/situation

• not ideal/slightly impossible to present the CS and US simultaneously or presenting the US before the CS

a stronger CS creates…

• a stronger CR

• ex: a louder bell → more salivation

first order conditioning

normal process of creating an association between and US and a CS

second (higher) order conditining

• using the CS from the first order conditioning to pair with a new stimulus and create a new CS

  • first CS becomes the US, and you can remove the initial US'

• US acts as the reinforcer for the conditioned reflex

• CS acts as an US (secondary reinforcer)

Why can’t higher order conditioning be continued to the 4th, 5th, 6th… etc.?

because extinction causes the cat to learn that nothing is producing food

Can second/higher order conditioning be reverse?

yes, will get the same results

generalization

• similar stimuli create similar responses

• ex:

  • a child sees a dog and goes to pet it

  • the child sees a cat (similar to a dog) and also goes to pet it

discrimination

• different stimuli create different responses

• the less similar the stimuli, the less similar the response will be

• ex:

  • a high-pitched tone (CS+) creates a stronger CR

    • could train over time to only have this tone produce the CR

  • a low-pitched tone (CS-) creates a weak CR

    • train by not pairing it with the US

What does the CS allow for?

• for the prep of the US

• ex:

  • the rabbit hears the tone (CS) and receives a shock (US)

    • its HR increases

    • now because the CS should be dangerous, the tone tells the body that shock is coming and warns it to prep

      • CS makes the rabbit’s HR decreases to compensate for homeostasis

What are the differences between how Pavlov interpreted classical conditioning and the current, modern view?

• Pavlov: the CS to CR is a conditioned reflex

• modern view: there is an association between the CS and the US; the CS provides important information about the US, so backwards conditioning (US before the CS) will fail

What are the differences between what Pavlov and Rescorla believed?

• Pavlov:

  • the CS was associated to the US through how many times the connection was made

    • ex: the dog eventually thinks of the bell in the same way as food

• Rescorla:

  • though the connection was made through contingency

    • the dog learned that receiving food (US) was contingent upon the bell (CS)

    • the dog does not mistake the bell for food

    • knows that there is a difference but still expects food when he hears the bell

How can a stimulus become a conditioned reinforcer?

through classical conditioning

partial reinforcement

• if you reinforce the rat sometimes (not every time)

  • extinctions take longer to occur

  • learning is stronger and more resistant to extinction

contingency

• dependency; likelihood of US depends on the CS’s presence or absence

• ex: likelihood of getting shocked (US), depends/is contingent on if the tone (CS) is playing or not

• matter more than contiguity in classical conditioning

Robert Rescorla Experiment

• was testing what it takes to make a signal work (more than contiguity)

• 3 groups of rates

  • tone is on 40% of the time so groups 1, 2, and 3 are getting shocked (US) exactly the same amount of time (shock is on 48/120s)

• all three groups have the same amount of contiguity (time), so they should all have the same fear conditioning

What happens when the tone for the groups is off?

• the groups receive different shocking, so contiguity is not the same

• group 1: shocked 40% of the time

  • no fear of the tone = no fear of conditioning

  • used to being shocked 40% of the time

    • no change, so the shock is not contingent on the tone

• group 2: shocked 20% of the time

  • some fear response

• group 3: shocked 10% of the time

  • associated the tone with MORE shocks

  • more fearful of the tone (being on vs off)

    • strongest conditioned fear response (CR) of the 3 groups

    • US (shock) is contingent on the CS (tone)

Where do the US and CS belong?

together (think nativism, evolution, and genetics)

Who believed that you could pair any CS with any CS

Pavlov; saw all associations as arbitrary and equipotential

belongingness

a CS and US could belong together; two stimuli work better together

Garcia and Koelling experiment

• opposite of equipotentiality

• 4 groups of rates with 2 different US and 2 different CS to see if some US and CS work better together

Garcia and Koelling experiment group 1

• gets light/tone (CS) with shock (US)

• did avoid the water with the light or tome

Garcia and Koelling experiment group 2

• gets the light/tone (US) with illness (US)

• did not avoid the water with a light or tone

Garcia and Koelling experiment group 3

• gets the saccharin taste (CS) with shock (CS)

• did not avoid the water with the saccharin taste

Garcia and Koelling experiment group 4

• gets the saccharin taste (CS) with illness (US)

• did avoid the water with saccharin taste

the biology behind the Garcia and Koelling experiment

• rates are taste and smell-based eaters

• in the wild rats need to avoid poisonous food

  • testing food and monitoring whether it makes them sick is crucial to survival

Garcia Effect

• taste aversion

• difficult to explain in classical

  • associations with CS and US happen in just ONE trial

  • less likely that extinction occurs

  • contiguity is not important (can present the CS hours before the US)

  • associations are selective (belongingness)

rats

• make associations between taste and illness

  • has blue-dyed water with sour taste leading to illness

  • the 2 stimuli presented

    • blue-dyed water with NO sour taste

    • clear water with a sour taste

  • rats avoid the CLEAR water with sour taste

quail

• makes associations between color and illness (visual stimuli)

  • has blue-dyed water with sour taste that leads to illness

  • then has two presented stimuli

    • blue-dyed water with NO sour taste

    • clear water with a sour taste

  • avoids the BLUE water with NO sour taste