Transcript B. F. Skinner - Kelley Kline

B. F. Skinner
Radial Behaviorism
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.
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.
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.
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
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)
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.
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.
Taste Aversion: A different
kind 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.

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.
B. Operant Conditioning

Learning occurs through the presentation of
rewards or punishments that influence
voluntary behaviors.
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.
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.
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
states that a behavior that is followed by a
satisfying consequence will be repeated.
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.
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.
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.
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.
The Skinner Box