14
Operant or Instrumental Learning
While Pavlov was studying reflexes in Russia, Edward Lee
Thorndike was a graduate student at Harvard observing cats and dogs
trying to get out of a cage he had built with a trap door (opened by the
animal pulling a string) in order to get food. He wanted to know which
animals were the smartest and how does the mind help animals cope.
From these studies, he concluded that animals (dogs, cats and
chickens) don't learn by imitation, don't reason, don't have insight,
and don't have good memories. At first, this must have pleased the
anti-evolutionists! But Thorndike did not glorify the human mind; in
fact, he concluded that all learning, even in humans, doesn't involve
the mind! Learning was for him simply the building of a connection
between the situation (S) and a response (R), depending on the
rewarding or punishing consequences to the animal. His basic
conclusion was: rewards strengthen the previous response and
punishment weakens the previous response.
In the 1930's B. F. Skinner built a "box" in which an animal could
get a pellet of food if it learned to press a bar or to peck a light.
Thousands of research studies have been done on animals in the
Skinner Box. Therefore, the most common textbook examples of
operant or instrumental conditioning are a rat pressing a bar in a
Skinner Box or a pigeon learning to peck a light to get food (See 4 in
Table 4.1). In real life, common examples of operant conditioning
would be working for a weekly pay check (5 in Table 4.1) and
disciplining a child to change his/her behavior. The use of rewards and
punishment has been known to man for thousands, maybe hundreds
of thousands, of years. These response tendencies may be built into
the species. Indeed, even animals punish their young for nursing too
vigorously or for misbehaving. During the 1960's and 70's, the use of
reinforcement, called behavior modification, became very popular with
psychologists, especially in schools and with the mentally or
emotionally handicapped.
The basic idea, straight from Thorndike, is seductively simple:
reward the behavior you desire in others or in yourself. This is
Skinner's key to utopia. There is also a parallel notion: if you don't
understand why you do certain things, go look for the possible rewards
following the behavior (Hodgson & Miller, 1982). Then change the
reinforcers if you want to change the behavior. This is a key method in
self-help. Behavioral analysis (understanding the antecedents and
consequences) and positive reinforcement are undoubtedly powerful
and under used methods but probably not the solution to all human
problems. Don't other factors besides reinforcement influence
behavior? What about hoped for rewards? plans? intentions? powerful
emotions?
Nevertheless, the Skinner box has undoubtedly given the world
valuable knowledge about different kinds of reinforcement schedules,
i.e. the consequences of reinforcing every bar press response vs.
every 3rd or 10th press vs. every 30 seconds of pressing the bar, etc.
