Transcript Taking it to the Limit

Neo-behaviorism:
Taking it to the Limit
Four Key Developments:
1. Tolman introduces “intervening
variables”
2. Hull incorporates “biological drives”
3. Thorndike establishes “reinforcement”
4. Skinner goes “operant”
Edward Tolman (1886-1959):
Purposive Behavior
• Tolman asserted that Watson’s strict stimulus-response
approach to psychology was only a study of “twitches.”
• Believed that environmental events and internal events
were both needed to explain behavior.
• Proposing his theory of Purposive Behavior, he believed
he could employ stimulus-response methods to study the
role of purpose in behavior.
– Avoided making inferences of behavior.
– To avoid such inferences, he created
“intervening variables,” or operationally
defined purposes.
Intervening Variables
• Intervening variables reflect the use of logical
positivism in psychology. Rather than assume
the meaning of behavior, Tolman created
operationally defined purposes for behavior.
• With his love of rats, he developed and
employed the now-famous rat mazes. The
purpose of the behavior in the maze – to find
the food.
• The rat maze was T-shaped. The rat walked up
to the decision point, one direction was an exit
(food), the other was a dead end (no food).
Intervening Variables (cont.)
• Famous study – He had three groups of rats.
Group “A” was given food at their exit,
groups “B” and “C” were not given food.
• After 10 days, group “A” showed more signs
of learning the maze (fewer errors) than
groups “B” and “C”. On the 11th day, he gave
group “B” food at the end of the maze. On
12th day, “B” went from acting like “C” (high
error) to acting like “A” (low error)
Intervening Variables (cont.)
• These results convinced Tolman that “B” rats
had learned the maze, but did not act like “A”
rats until they had the same purpose.
• Tolman made internal “intervening variables”
– e.g., purpose – compatible with behavioral
research.
• Thanks to him, concepts such as
“hypothesis,” “confirmation,” “expectation,”
“belief,” and “cognitive maps” also became
part of behavioral research.
Clark Hull (1884-1952):
Hypothetico-Deductive Theory
• Expanded on the use of intervening variables, but
opposed all internal (mental) speculations..
• Hull replaced “purpose” with biological needs.
– Biological needs created “drives.”
– Behaviors which fulfilled the needs would be
reinforced by “drive-reduction.”
– Learning was “habit strength,” or the strength
of the connection between a situation and the
need-fulfilling (drive-reducing) response.
Hypothetico-Deductive Theory
• Hull’s theory was an effort to create a
complete model for learning.
• It is based on the idea of stimulus-organismresponse – using intervening variables to
represent the organism in the research.
– S-O-R, not S-R
• Hull’s theory, however, was very complex. It
had 17 universal intervening variables and
133 theorems (rules of behavior).
Hypothetico-Deductive Theory
(Cont.)
• “Reaction potential” was one of the more famous and
useful theorems, and is commonly used to represent
Hull’s theory.
• Reaction potential = “habit strength” x “drive”
– As shown in the textbook, Hull liked to
present his theorems as mathematical
formulas.
– In this case, the formula states that drives
and habits have a multiplicative effect on
responses.
Edward Thorndike (1874-1949
• Law of Effect: of several
responses made to the
same situation
– those which are
accompanied or closely
followed by satisfaction
….will be more likely to
reoccur
– those accompanied or
closely followed by
discomfort will be less
likely to occur
Law of Effect: Basic Points
• Law of Effect
• Some randomness to behavior (variability)
• Behaviors that lead to pleasurable
consequences are “stamped in”
• Those that have noxious consequences
are weakened.
B.F. Skinner (1904-1990)
• Skinner developed a form of behaviorism
which he called “operant” conditioning,
which differed fundamentally from the
original “classical” conditioning.
• Classical conditioning was based on the
ability to add conditioned stimuli to an
unconditioned stimulus-response set,
resulting in conditioned responses.
Operant conditioning was based on the
ability to influence responses with rewards
and punishments – “reinforcing”
responses.
Environment and Behavior
• In the spirit of Darwin, Skinner viewed the
environment as “selecting” behaviors,
rather than “stimulating” behaviors.
• Environmental influence manifested itself
in the form of rewards and punishment for
various behaviors.
– Rewards could be a desired gain or the loss of
something undesired.
– Punishment could be an undesired gain or
loss of something desired.
Reinforcing Behavior
• Skinner showed how rewards and punishment
could shape behavior, and showed the varying
effects of schedules of reinforcement.
– Fixed intervals – e.g., every fifth time
– Fixed ratios – e.g., every night, every Sunday
– Variable intervals – after a random number of
times (the gambler’s reinforcement)
– Variable ratios – every now and then
Behavioral Therapy
• Skinner assumed that abnormal behavior was
learned, and hence, normal behavior could
be learned.
• Therapy, in turn, was viewed as an act of
removing the reinforcements of undesirable
behavior and providing reinforcements of
desirable behavior.
• Behavior therapy has been successful in
treating fears, disorders, and unhealthy
behaviors.
• A famous example is the “token economy” …
Token Economy
• Skinner’s methods of behavioral
reinforcement have been used in institutions
for the mentally ill as well as in criminal
detention facilities.
• Tokens are given to patients after desirable
behaviors, and taken away from patients
after undesirable behavior.
• The patients are given the opportunity to use
the tokens for a variety of desirable things
such as snacks, entertainment, and privacy.
Token Economies
• Institutions using token economies have
reported a higher success rate with patients
than those without token economies.
• Famous philosophical question – what is the
difference between our currency-based
economy and a token economy? In other
words, how much is money related to (or
separate from) behavioral reinforcement?
Behaviorism Encounters
Problems
• The decade of the 50’s witnessed a growing
dissatisfaction with behaviorism.
• Many behaviorists were becoming disenchanted with
overly simplistic and presumably incomplete
explanations.
• In the U.S., alternatives to pure behaviorism started with
Tolman’s purposeful behavior, but his theory was seen
more as a “friendly amendment” than a viable
alternative.
• Basically, the limitations of behaviorism were becoming
too obvious to ignore.
The Problem of Language
• The biggest problem for behaviorists was not rival
theoretical paradigms, but that some real-world activity
appear unexplainable by behaviorism.
• For example, behaviorists had problems explaining the
acquisition of languages.
• With a primary language (a language learned within the
development of language skills), children learn suddenly
and holistically.
• With learning a secondary language (after having
language skills), though, the learning is more similar to
behavioral trial-and-error learning.
The Problem of Language
(Cont)
• The behaviorists had problems explaining the
acquisition of language, but more importantly, a
purely cognitive explanation was becoming a
world-renowned theory.
• In 1957, Noam Chomsky presented his first
account of the Language Acquisition Devise
(LAD). It replaced the grammar-theories of
language with a syntax-theory of language.
• In short, Chomsky proposed that we all have an
innate mental mechanism that relates soundpatterns with syntactic meanings (the LAD).
Expertise Problems
• In the real world, a novice is relatively slower
and less skilled than an expert. With pure
behaviorism, though, the vast experiences of the
expert are supposed to be a burden.
• Expertise presented a similar problem as those
of language acquisition. Experts can mentally do
more, and can do it faster.
• A jogger’s analogy … as the expert “learned” to
jog longer distances, the expert would finish
more quickly each time the distance got longer.