Ivan Petrovich Pavlov (1849-1936) shared Sechenov's goal of creating a totally Objective psychology. Pavlov focused his study on the conditioned and unconditioned stimuli that control behavior and on the physiological processes that they initiate. For Pavlov all human behavior is reflexive.
The P-O-X Theory (Balance Theory) refers to the idea that relationships among one person (P), the other person (O), and an attitude object (X) may be either balanced or unbalanced. It is a conceptualization advanced by Fritz Heider which assumes that interpersonal relationships can be either balanced (integrated units with elements that fit together without stress ) or unbalanced (inconsistent units with elements that conflict with one another). Heider believed that unbalanced relationships create an unpleasant tension that must be relieved by changing some element of the system .