Contingency Theory of
Classical Conditioning
For Pavlov, the key variable in associative learning
was the number of times the CS was paired with the
US.
The Pairings Principle:
As the number of pairings increases, the strength
of the association between CS and US increases.
This was because the CS became a more reliable
signal that the US was going to occur.
Contingency Theory of
Classical Conditioning
In the 1960s, an alternative theory was proposed by
Robert A. Rescorla, the Contingency Theory.
Rescorla agreed with Pavlov that for learning to
take place, the CS had to be a useful predictor of
the US.
But he disagreed on what made the CS a useful
predictor. It was more complicated than the
number of CS-US pairings.
He maintained that it was the contingency
between the CS and US.
Contingency Theory of
Classical Conditioning
Generally, “contingent” means “conditional”.
In classical conditioning, if the CS is paired with
the US, then the US is contingent (conditional) on
the CS. You can predict
from
.
But more complex relationships can be arranged.
Contingencies vary in both degree and direction:
Positive contingency: the CS signals an increase in
the probability that the US will occur (compared to
before the CS).
Negative contingency: the CS signals a decrease in
the probability that the US will occur (compared to
before the CS).
Contingency Theory of
Classical Conditioning
Example of positive contingency:
Example of negative contingency:
Contingency Theory of
Classical Conditioning
You can also have a zero contingency where the CS
predicts neither an increase nor a decrease in the
probability of the US. Everything’s random.
Example of zero contingency:
The food can occur anytime. The bell is irrelevant.
Contingency Theory of
Classical Conditioning
According to the theory, learning only takes place
with the positive and negative contingencies.
With the zero contingency, the CS is ignored, even if
it is sometimes paired with the US.
TWO KINDS OF CONDITIONING
Excitatory conditioning: the subject learns to
perform a certain response, like salivating when the
bell is rung.
Inhibitory conditioning: the subject learns to
withold a certain response by forming a
“conditioned inhibitory response.”
This is like a wall. It blocks the salivation.
Contingency Theory of
Classical Conditioning
KEY POINTS
• The positive contingency produces
excitatory conditioning.
• The negative contingency produces
inhibitory conditioning.