Formal theory still remains a common form of investigation in the political science. It developed among the first methodologies to the study in the 20th century. Formal theory is also known as a rational choice theory primarily used in positivist studies. It strives to draw logical conclusions from interrelations between political concepts. The method consists of a game theory and spatial theory. Game theory deals with strategic interaction of the subjects in a competitive and cooperative environment. Spatial theory investigates the behavior of subjects in different contexts in spatial distance.
Formal theory derives its assumptions from already existing principles. Rational choice is one of them. It prescribes that actions of individuals are intentional and motivated by the real world circumstances. In its turn, rational choice is based on three more principles – comparability, transitivity, and self-interest. Comparability is a chance to discover alternatives and make a rational choice. Transitivity points at a clear interrelation between the options. It allows people to evaluate all options and make a considerate choice. Self-interest implies that individuals are motivated to choose what is best for themselves. It is very rational that individuals seek to get the largest possible benefit.
The spatial model is used to analyze voting in a one- or two-dimensional space. Political choice is a point in the space where all subjects have their preferences. Each subject prefers the choice that lies closer to their point of interest. Spatial models are also used to determine social choice, voting, and political behavior.