Limitations of Classical Conditioning
o
All classically conditioned responses must
involve a reflex
o
Therefore, what can be learned is limited
o
So, how do animals and humans learns things that
are not associated with reflexes?
Thorndike
E. Thorndike (1874-1949)
§
Law of Effect
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Thorndike’s principle that behaviors followed by
favorable consequences become more likely, and behaviors followed by
unfavorable consequences become less likely
Early Operant Conditioning
o
E.L. Thorndike
(1898)
o
Puzzle boxes and
cats
Operant Conditioning
§
B.F. Skinner
(1904-1990)
§
elaborated Thorndike’s Law of Effect
§
developed behavioral technology
Operant Chamber
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Skinner Box
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chamber with a bar or
key that an animal manipulates to obtain a food or water reinforcer
§
contains devices to
record responses
Operant Conditioning
§
Reinforcer
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any event that strengthens or increases the rate of the
behavior it follows
§
It can be either
positive (pleasurable) or
§
Negative (unpleasureable)
Operant Conditioning
What are some common examples?
o
Friend increasingly talks about sports (increase
in a positive reinforcer– attention)
o
Parent increasingly yells or hits child (decrease
in a negative reinforcer—tantrum)
o
Keep playing slot machine after winning some
money (increase after positive--$)
o
Husband increases housework after continually
being rewarded by wife….
Principles of Reinforcement
§
Primary Reinforcer
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innately reinforcing
stimulus
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i.e., satisfies a biological need
§
Conditioned or Secondary Reinforcer
§
stimulus that gains its
reinforcing power through its association with primary reinforcer
For example:
money
Chaining
o
Can connect or chain secondary reinforcers together
n
If I work hard I get credit points which lead to
money which lead to pleasure
n
If the rat pulls a string it lowers a bar which
when pressed leads to food
Shaping
§
operant conditioning procedure in which reinforcers
guide behavior toward closer approximations of a desired goal
Demonstration of Shaping
o
Two volunteers
B.F. Skinner