B. F. Skinner

1. B. F. Skinner Radial Behaviorism

2. I. Biography • Burrhus Frederick Skinner was born in Susquehanna, Pennsylvania in 1904. • His father, a lawyer, announced the birth in the local town paper as “The town has a new law firm: Wm. A. Skinner & Son.” • However, all efforts to shape Skinner into the legal professional failed. • Skinner went to Hamilton College to study English to become a writer.

3. Biography (contd) • Skinner had the chance to meet the poet, Robert Frost. Frost read some of Skinner’s work & encouraged him to keep writing. • Although Skinner spent 2 years writing, he felt he had produced nothing of quality at the end & changed fields. • He enrolled in Harvard University to study psychology. After getting his degree he went to the University of Minnesota & Indiana University before returning to Harvard.

4. Biography (contd.) • Skinner was incredibly productive producing many papers, books, & even a fiction novel called “Walden Two” about a utopian society based on principles of reinforcement. • Skinner remained productive till he died from cancer.

5. II. Basic Principles of Conditioning • Behaviorists explain behavior, for both humans and lower animals, in terms of learning experiences or conditioning. • They don’t deny influence of genetics, but downplay its relative importance. • There are essentially two basic forms of conditioning: classical (Pavlovian) & operant (instrumental) conditioning

6. A. Classical Conditioning • Pavlov’s classic dog salivation study • Step 1: Meat Powder (UCS)---------Salivation (UCR) • Step 2: Bell (CS) -------- • ---Meat Powder (UCS)--Salivation (UCR) (pair bell with meat) • Step 3: Bell (CS)--------------------Salivation (CR)

7. Watson & Rayner (1920) • Conditioned emotional responses in an 11-month-old infant (“Little Albert”). • Used classical conditioning to get infant to fear white furry objects (rats, Santa’s beard, fur coat, etc.). • They did this by presenting a loud obnoxious noise (UCS) whenever “Albert” showed an interest in the white furry rat (CS). Soon, child came to fear white furry objects without presence of noise.

8. Classical Conditioning: S-R associations • It is likely that many of our preferences for food, clothing, & even friends can be determined through this process. • E.g., Riordan & Tedeschi (1983) found that anxious Ss found another person unattractive after sitting in a waiting room with him or her. • The researchers reasoned that the association of the anxiety with the other person created a negative response to him or her.

9. Taste Aversion: A differentkind of conditioning • Why is it different from other types of classical conditioning?? • It only requires 1 trial for learning to occur. • Pairing a noxious substance with food or drink, elicits nausea/vomiting—leading to avoidance of the food or drink.

10. Problems with Classical conditioning • 1. There is only so much learning that can take place using this method (reflexive associations). • 2. Without additional learning, conditioned S-R associations probably won’t last (extinction). • 3. Two events presented together will not always produce an association (Rescorla, 1988). • 4. Some stimuli are easily associable, whereas others might be impossible.

11. B. Operant Conditioning • Learning occurs through the presentation of rewards or punishments that influence voluntary behaviors.

12. E.L. Thorndike: Law of Effect • Thorndike was interested in how learning occurred through a series of rewards & punishments. • Using cats as Ss, he placed them into “puzzle boxes” from which they had to escape to get a food reward next to the box. • The cats could escape by doing a number of things: pressing levers, pulling a string, or tilting a pole.

14. Thorndike contd. • Initially the cats spent a lot of time trying to escape to no avail. Suddenly, the cat would through trial-&-error figure it out. • Once this occurred, kitty was placed back in the box to do it again. • Thorndike measured the time required to escape the box (escape latency) & plotted it.

16. The escape latency decreased with repeated trials. • Thorndike concluded that the act of opening the door served as a reinforcement for the cat. • The probability of the cat escaping from the box increased over trials, because the cat was continually reinforced for escaping the box. • From this he formulated the Law of Effect which statesthat a behavior that is followed by a satisfying consequence will be repeated.

18. Skinner’s Work: • Skinner showed that by presenting animals or people with rewards & punishments you could shape behavior. • Initially, to get a new behavior to appear & then be conditioned, you have to use shaping. • Shaping involves presenting a reinforcement for each successive approximation of a desired behavior. • E.g., if we want to shape lever pressing in rats, we would reinforce any behavior that even remotely resembles lever pressing.

19. Reinforcement-strengthens a behavior • 1. Positive Reinforcement: Strengthens a response by presenting something that is perceived as appetitive (pleasant) after a behavior is emitted. • E.g., a good grade received after studying for an exam, a food reward for pressing a lever, etc. • 2. Negative Reinforcement: strengthens a response by removing an aversive stimulus after a behavior is emitted. • E.g., people smoke more, to reduce aversive sensations associated with nicotine withdrawal.

20. Punishment: Two forms • 1. Positive Punishment - apply an aversive stimulus when an undesired behavior occurs. Must be immediate to be effective. • E.g., presenting lemon juice on a toddler’s tongue immediately after he or she bites. • 2. Negative Punishment - remove an appetitive stimulus when an undesired behavior occurs. • E.g., revoking a teenager’s driving privileges if they get a speeding ticket.

21. Skinner Box • Skinner created an apparatus that would present rewards to an organism (animals & humans!!) based on their behavioral responses. • He even had his daughter stay in the box for several experiments.

22. The Skinner Box