What is the relationship between research methods in the physical and behavioral sciences?
In the physical sciences, the main goal of research is to find functional relationships between variables, such as the relationship between the time it takes for a ball to move a fixed distance down an inclined plane and the inclination of the plane. Physical scientists do research by manipulating variables — the independent variables — and measuring the effect of this manipulation on other variables — the dependent variables. This approach to research was adopted by the behavioral sciences under the assumption that the goal of the behavioral sciences was the same as that of the physical sciences: to determine functional relationships between variables. But PCT shows that the physical science approach to research produces misleading results when used to study closed loop control systems. Research in the behavioral sciences should be aimed at determining what perceptual variables living systems control. This kind of research is done using a method based on control engineering called
