Psychology Chapter 9

Section 4: Principles of Operant Conditioning

Wade and Tavris © 2005 Prentice Hall 9-2

The “Skinner Box”• When a rat in a

Skinner box presses a bar, a food pellet or drop of water is automatically released.• Similar boxes exist

for pigeons & many other species.

• Extinction- procedure that causes a previously learned response to stop–Occurs when the reinforcer that

maintained the response is removed or is no longer available–gradual

Stimulus Generalization & Discrimination

• Generalization occurs when responses generalize to the stimulus that were not present during the original learning situation but resemble that original stimulus

• Sometimes a human or animal learns to respond to a stimulus only when a discriminative stimulus is present

• The discriminative stimulus signals whether a response, if made, will pay off• Traffic lights, doorbells, ringing

phone, etc

Learning on Schedule

• Continuous Reinforcement: –A reinforcement schedule in which a

particular response is always reinforced.• Intermittent (Partial) Schedule of

Reinforcement: –A reinforcement schedule in which a

particular response is sometimes but not always reinforced.–Explains why people get attached to “lucky”

hats, etc

• Patterns of reinforcement affect the rate, form, & timing of behavior

• If you want a response to persist after it has been learned, you should reinforce it intermittently, not continuously

• If you are going to extinguish an undesirable behavior by ignoring it, you must be consistent in with holding reinforcement

• Shaping–For a response to be reinforced, it must first

occur–You start by reinforcing a tendency in the

right direction & then you gradually require responses that are more similar to the final, desired response–Successive approximations–Animal training- seeing eye dogs

Biological Limits on Learning

• Operant conditioning always works best when they capitalize on inborn tendencies• Beware of instinctive drift• Humans can be affected by biology,

genetics, & the evolutionary history of our species

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Skinner: The Man and the Myth

• Burrhus Frederick Skinner, 1904-1990–Better known as B.F.

Skinner• Much misinformation is

circulated about his life & work–e.g., his daughters grew up

normal, despite rumors that they were institutionalized