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?


E. Thorndike (1874-1949)

§         Law of Effect

§         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

§         Skinner Box

§         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

§        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

§         innately reinforcing stimulus

§         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


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


§        operant conditioning procedure in which reinforcers guide behavior toward closer approximations of a desired goal


Demonstration of Shaping

o      Two volunteers

B.F. Skinner