Educational Psychology—Limitations and Possibilities

202 The Praeger Handbook of Education and Psychology
spent five postdoctoral years working in William J. Crozier’s laboratory. Crozier, who was an
experimental biologist, had a major influence on Skinner’s philosophy and behavioristic position.
Crozier, in contrast to psychologists who focused on studying the processes going on inside an
organism, passionately believed in studying the behavior of an organism as a whole. This was
the philosophy that paralleled Skinner’s goal of relating an organism’s behavior to experimental
conditions.
In 1936, Skinner joined the faculty of the University of Minnesota. Skinner’s tenure at the
University of Minnesota can be characterized as remarkably productive wherein he was heavily
engaged in scientific inquiry yet found the time to write a novel entitled Walden Two. Skinner
stayed at the University of Minnesota for nine years, had a two-year stay at Indiana University as
Chair of Psychology, and eventually returned to Harvard, where he remained for the rest of his life.
SKINNER’S DEVELOPMENT OF OPERANT CONDITIONING
Skinner remained consistent in his philosophy that the organism must literally operate upon
its environment. This is in total contrast to Pavlovian conditioning, where the organism plays a
very passive role. Furthermore, Skinner believed that antecedent events need to be considered
when studying an organism’s behavior and that an organism’s behavior can be controlled by
systematically manipulating the environment in which the organism is operating. These comprise
the foundation of B.F. Skinner’s operant conditioning theory.
As the organism operates in its environment, it encounters a unique type of stimulus that
increases the organism’s response. In operant conditioning theory, a stimulus that increases the
likelihood of the organism’s response is called a reinforcement or a reinforcer. Hulse et al. (1980)
formally defined a reinforcer as a “stimulus event which, if it occurs in the proper temporal
relation with a response, tends to maintain or to increase the strength of a response or of a
stimulus-response connection” (p. 18). In contrast to a reinforcing stimulus or a reinforcer, an
organism operating in its environment can also be exposed to unique types of stimuli that decrease
the organism’s response. A stimulus that decreases the likelihood of the organism’s response is
referred to as aversive stimuli.
It is worth noting that operant conditioning is also called instrumental conditioning because the
organism plays an instrumental role in developing the stimulus–response connection. This can
be best explained by thinking of an experiment involving a rat in a box. In the box, known as a
Skinner box, is a lever that when depressed delivers a food pellet into the box. The rat is operating
in its environment and accidentally depresses the lever. A food pellet is then delivered into the
box. In time, the rat will vigorously depress the lever to get more food pellets. Let us now examine
the experiment through the operant conditioning theory. The rat (the organism) is operating in the
box (the environment) and accidentally depresses the lever (operant response) and receives a food
pellet (reinforcing stimulus). The rat then depresses the lever vigorously (increase in response) to
receive more food pellets (reinforcing stimulus). This stimulus–response connection is established
over time and this series of stimulus–response connections is considered as behavior. One can
then ask, what if the reinforcing stimulus (i.e., the food pellet) is no longer delivered? Over
time, the rat will stop the lever-pressing response because the reinforcing stimulus is no longer
available. It could be said that the behavior has been extinguished. In the operant conditioning
theory, this phenomenon is called extinction.
While engaged in heavy operant conditioning experimentation, Skinner ran low on food pellets
so he had to reduce the number of food pellets that were given to the rats as reinforcement.
Interestingly, even though the rats received less reinforcement, the operant behavior continued
to be exhibited over a period of time. This led Skinner to the discovery of the schedule of
reinforcement.