Classical Conditioning

A. Definitions1. Classical conditioning: learning that takes

place when originally neutral stimulus comes to produce a conditioned response because of its association with an unconditioned stimulus

2. An unconditioned stimulus (UCS or US) reflexively produces an unconditioned response (UCR or UR), even in the absence of previous training

3. A conditioned stimulus (CS) is a stimulus that has come to elicit a conditioned response (CR) because the organism associates the conditioned stimulus with the unconditioned stimulus

- Initially called the “neutral stimulus”

So let’s go back to Jaws…

Pavlov’s Classical Conditioning: Pavlovian Response or “Psychic Reflex”

• accidental psychologist: studying digestion initially

• theory links to emotion, temperament, neuroses, and language

Pavlov’s Experiment

Unconditioned vs. Conditioned Responses

• In Pavlov’s demonstration UR = CR– Salivation

• Although UR and CR consist of same behavior, there are subtle differences– CR usually weaker or less intense

• Sometimes UR and CR are different but related– Animal given a shock, UR = pain, CR = fear

of imminent pain

Conditioned Reflex

• Classically conditioned responses described as reflexes – Involuntary and automatic

Trials• How long does it take to learn something?

Classical Conditioning Applications

1. Conditioned Fear and Anxiety• Phobias• Irrational fear due to classical conditioning

• Fear of dentist drill

• Careful though – susceptibility of irrational fear is mostly based on genetics… how?

2. Emotional Responses– Arousal

• Smell of first love’s cologne/perfume

3. Physiological Responses

• Sexual arousal in quails– Conditioned to become aroused by nonsexual

stimuli– Conditioned to elicit increased sperm release– Fetishes for inanimate objects

• Difficult to test connections to human sexual fetishes

What’s up, girl?

Nah, it’s cool, I’m going to

chill with my boot… what’s

up, girl?

4. Evaluative Conditioning of Attitudes (evaluative conditioning)

• Changes in the liking of a stimulus that result from pairing that stimulus with other positive or negative stimuli– MARKETING

– http://www.youtube.com/watch?v=pfvq2Gf6UE8

B. Acquisition: initial stage of learning something1. Involves repeated pairings of the CS and

the UCS/US

2. Acquisition Paradigms (patterns)

• What are the different ways in which the initial learning can take place?

a. Trace Conditioning– CS is presented and terminated BEFORE presentation of

the UCS/US– Conditioning often effective when the interval BETWEEN

presentation of the CS and the UCS/US is about a half second

– Fear studies; dependent on usage of hippocampus– http://www.youtube.com/watch?v=PsGjh6ul7mE

b. Delay Conditioning– Occurs when CS is presented and continues at

least until the UCS/US is presented– Often times paired with trace conditioning in studies– Hippocampus-independent– Fear expression

Fear Expression in Rats

c. Simultaneous Conditioning– Occurs when CS and the UCS/US are

presented and terminated at the same time– Anti-smoking ads

d. Backward conditioning – Occurs when the UCS/US is presented before

the CS– http://www.youtube.com/watch?v=fT6IWAIf580

e. Temporal conditioning– Occurs when the nominal CS is a fixed period

of time between presentations of the UCS/US– Combined with trace conditioning based on a

period of time• i.e. dog starts to salivate at 7:59am because s/he

is fed at 8am everyday

C. Extinction

1. A procedure that leads to gradual weakening and eventual disappearance of CR

2. Involves repeatedly presenting CS without pairing it with UCS/US

D. Spontaneous Recovery

1. Occurs when previously extinguished CR suddenly reappears after a period of training

2. Renewal effect• If a response is extinguished in a different

environment than where it was acquired, the extinguished response will reappear if the animal is returned to the original environment where the acquisition took place

• Proves that extinction is a suppression not an erasure (unlearning)

• Explains drug abuse and relapse and difficulty getting rid of phobias permanently