Wikipedia
Functional psychology or functionalism refers to a psychological philosophy that considers mental life and behaviour in terms of active adaptation to the person's environment. As such, it provides the general basis for developing psychological theories not readily testable by controlled experiments and for applied psychology.
Functionalism arose in the U.S. in the late 19th century as an alternative to structuralism. While functionalism never became a formal school, it built on structuralism's concern for the anatomy of the mind and led to greater concern over the functions of the mind, and later to behaviourism.
Usage examples of "functional psychology".
I don't think you'll ever learn the functional psychology of the dog from a mutie.
Contemporary history, societics, economy, geopolitics, a new thing they call existentietics, functional psychology - oh, and other things, and practical subjects, such as engine maintenance.