> The relation between the controller and the controlled is reciprocal. The scientist in the laboratory, studying the behavior of a pigeon, designs contingencies and observes their effects. His apparatus exerts a conspicuous control on the pigeon, but we must not overlook the control exerted by the pigeon. The behavior of the pigeon has determined the design of the apparatus and the procedures in which it is used. Some such reciprocal control is characteristic of all science. As Francis Bacon put it, nature to be commanded must be obeyed. The scientist who designs a cyclotron is under the control of the particles he is studying. The behavior with which a parent controls his child, either aversively or through positive reinforcement, is shaped and maintained by the child's responses. A psychotherapist changes the behavior of his patient in ways which have been shaped and maintained by his success in changing that behavior. A government or religion prescribes and imposes sanctions selected by their effectiveness in controlling citizen or communicant. An employer induces his employees to work industriously and carefully with wage systems determined by their effects on behavior. The classroom practices of the teacher are shaped and maintained by the effects on his students. In a very real sense, then, the slave controls the slave driver, the child the parent, the patient the therapist, the citizen the government, the communicant the priest, the employee the employer, and the student the teacher.
-- B F Skinner