The theory of interhemispheric asymmetry of the brain, according to which each hemisphere of the brain is responsible for specific functions. The left hemisphere handles language abilities (speech, reading, writing), while the right hemisphere specializes in processing information expressed through symbols and images.

The Five-Factor Model of personality structure (T.A. Widiger, C. Crego, A.G. Shmelev) consists of five major domains: neuroticism (or emotional instability vs. emotional stability), extraversion (with the opposite pole being introversion), openness to new experiences (or originality), agreeableness (with the opposite pole being antagonism), and conscientiousness (or restraint vs. impulsivity).

The communicative approach: involves a conversation with the subject to clarify their responses to a few questions, in order to obtain more objective information about their emotional state.