Psy 342 Learning & Memory

Chapter 3

Basic Principles of Classical Conditioning

I. Pavlov’s Experiments

What was the unconditioned stimulus? 

What was the  unconditioned reflex (or response)?

What was the conditioned stimulus?

What was the conditional reflex (or response)? 

II. Classical Conditioning Terminology

    A. Unconditioned Stimulus (US) 

 An event that consistently and automatically elicits an unconditioned response

    B. Unconditioned Response (UR)

An action that the unconditioned stimulus automatically elicits

    C. Conditioned Stimulus (CS) 

Initially a neutral stimulus. After repeated pairings with the unconditioned stimulus, the CS elicits the same response as the US.

    D. Conditioned Response (CR)

The response elicited by the conditioned stimulus due to the training. 

Classical conditioning is a method used to study associative learning. What is an association?

III. Examples of Classical Conditioning

IV. Contingency

If the CS is to be a reliable signal for the US, the occurrence of the CS and the occurrence of the US must be correlated in some way.

    A. Positive Contingency

Two stimuli tend to occur together and neither tends to occur when the other is absent

Classical excitatory conditioning

    B. Negative Contingency

One stimulus regularly precedes the absence of another stimulus that is present at other times

Classical inhibitory conditioning

    C. No Contingency 

The CS is NOT a reliable signal for the occurrence or absence of a US

Would you predict classical conditioning to occur in this situation?

V. Methods

    A. Human Conditioning Paradigms

Most often studied in humans—Eye blink reflex and skin conductance response

Classical conditioning of the eye-blink response

SCR—A measure of the electrical conductivity of the skin, which varies with subtle changes in the subject's emotionality

 Animal paradigms must be suited to the behavioral repertoire of the particular species

Rabbits—nictitating membrane paradigm—like eye blink conditioning paradigm in  humans 

A couple of classical conditioning methods use less traditional USs (stimulus doesn't elicit reflexive response and/or responses are measured indirectly.

Conditioned Taste Aversion--

CS--
US--

UR--

CR--

Evaluative Conditioning--neutral stimulus is presented along with a stimulus that already evokes an affective evaluation. UR and CR are participant's affective rating

VI. Relationship between CS and US

How are CS and US arranged in time?

    A. Temporal Order--What is the role of contiguity?

Why is there such a difference between forward (delayed & trace) versus simultaneous and backward pairings?

    B. CS-US Interval

What is the range of optimal CS-US intervals?

**Conditioned taste aversion is an exception

    C. Number of CS-US Pairings

 Learning/Acquisition curves reflect ________________?

   D. Prior Experience with CS or US

How does our experience with a CS or a US affect the degree to which these stimuli will promote conditioning?

latent inhibition—Pre-exposures to a CS alone can hinder later conditioning involving that CS (Lubow & Moore, 1959)

Possible explanations:

habituation

interference

    E. CS-US Relevance

Are the CS and US typically related in the natural environment? 

For the US of shock, the more salient CS was ______________?

For the US of poison, the more salient CS was ______________?

 Seligman (1970)--genetic preparedness

    F. Presence of Other Stimuli During Conditioning

              Compound Conditioning

When two or more conditioned stimuli occur together before the US, each may become conditioned but to varying degrees

What's the basic compound procedure?
    Training
    Test Compound
    Test individual CSs

Which CS acquires more conditioning and which acquires less can be altered in several ways:

                  1. Overshadowing --vary salience (noticeability) of the individual CSs in the compound (Kamin, 1969)--conditioned emotional response (CER) with rats

The general perceived strength of stimuli is commonly referred to as their salience. Although it might be related to the physical measurable intensity of stimuli, salience refers to the intensity of the subjective experience of stimuli, not of the objective intensity of the stimuli themselves. Salience, as subjective experience, varies between individuals, and, more importantly, between species. Salience depends on some combination of the physical characteristics of stimuli and of the sensory systems of the perceiver.

                  2. Onset of CSs--Egger and Miller (1963)--salivary conditioning with dogs

                  Blocking

Kamin (e.g., 1969) 

Why was conditioning to the added stimulus blocked? 

VII. Conditioning Without an Explicit US

Conditioning can take place in some cases EVEN WHEN NO EXPLICIT US APPEARS TO BE PRESENT

      Higher Order Conditioning

Second-Order Conditioning--When conditioning results from the pairing of a novel CS with a previously conditioned CS (a form of higher order conditioning)

      Sensory Preconditioning

Sensory preconditioning first involves the paring of two CSs. Later, when one of the stimuli is paired with a US and becomes capable of producing a CR, the organism reacts to the other CS as if it, too, had been paired with the US. 

XI. Extinction

The decrease and eventual disappearance of a conditioned response once a CS is no longer a reliable signal for a US

Researchers have argued about the precise mechanism that controls extinction. 

Research shows that:

Extinction does NOT RESULT FROM FORGETTING

Extinction does NOT INVOLVE LOSS of THE ASSOCIATION formed during conditioning

What is spontaneous recovery of the response?

How do these variables affect the rate of extinction?

(1) Number of CS-US conditioning trials presented during actual conditioning

XII. Application of Classical Conditioning Procedures

    A. Watson & Rayner (1920)

   The Search for Little Albert

§        B. Extinction procedures for treatment of some phobias

            Extinction as therapy 

             Systematic desensitization