Interpersonal compatibility

Although various concepts of interpersonal compatibility have existed from ancient times (see, e.g., Plato's Lysis), no general theory of interpersonal compatibility has been proposed in psychology. Existing concepts are contradictory in many details, beginning with the central point—whether compatibility is caused by matching psychological parameters or by their complementarity. At the same time, the idea of interpersonal compatibility is analyzed in non-scientific fields (see, e.g., Astrological compatibility).

Among existing psychological tools for studying and/or measuring interpersonal compatibility, the following are noteworthy:

• A test of interpersonal compatibility proposed by Timothy Leary
• A three-factor hypothesis (inclusion, control, and affection/openness) by William Schutz (further developed into FIRO-B questionnaire)
• Hans Jurgen Eysenck's hypothesis on compatibility between temperaments
• Social psychological research on similarity of interests and attitudes
• Compatibility test pamphlets of the 1930s and early computer dating of the 1950s, developed by George W. Crane
• Hypothesis of compatibility between personality attitudes by Russell Ackoff and Frederick Edmund Emery,^[1]
• DMO tool by Lyudmila Sobchik (DMO stands for Interpersonal relations diagnostics, Russian: диагностика межличностных отношений)

Other hypotheses of intertype relationships were later proposed by adherents of MBTI (D. Keirsey's hypothesis of compatibility between Keirsey temperaments^[2]).

The following problems may be reasons for the absence of a theory of psychological compatibility:

• Lack of generally accepted criteria for measuring compatibility ("degrees of compatibility")
• The terms compatibility and matching, although not identical, are often confused in common speech (the first rather comprises complementarity and the second similarity of partners)
• The problem's unclear status in social science (the problem may belong to social psychology, sociology, personality psychology etc.)
• Different psychological theories propose different parameters of personality, but only few of them are generally accepted among psychologists (e.g. cognitive styles); still, even generally accepted criteria may be irrelevant to interpersonal compatibility
• Some, if not all personality parameters (even genetically determined ones), may change over time and/or due to interpersonal interaction
• The non-traditional view of psychological dependency, which is not considered drug dependency, but rather a need (unilateral or mutual) for somebody else's psychological support that one cannot or can hardly provide by him/herself.

It has been suggested that the major histocompatibility complex (MHC) plays a role in the selection of potential mates, via olfaction. MHC genes make molecules that enable the immune system to recognize invaders; generally, the more diverse the MHC genes of the parents, the stronger the immune system of the offspring. It would therefore be beneficial to have evolved systems of recognizing individuals with different MHC genes and preferentially selecting them to breed with.

Yamazaki et al. (1976) showed this to be the case for male mice, which show a preference for females of different MHC. Similar results have been obtained with fish.^[3]

In 1995, Swiss biologist Claus Wedekind determined MHC influences both body odors and body odor preferences in humans, and that the women's preferences depend on their hormonal status. In an experiment, a group of female college students smelled T-shirts that had been worn by male students for two nights, without deodorant, cologne or scented soaps. Overwhelmingly, the women preferred the odors of men with dissimilar MHCs to their own. However, their preference was reversed if they were taking oral contraceptives.^[4] The hypothesis is that MHCs affect mate choice and that oral contraceptives can interfere with the preference for variation. A study in 2005 on 58 test subjects confirmed that taking oral contraceptives made women prefer men with MHCs similar to their own.^[5] Several follow up studies have confirmed the belief that paternally inherited HLA-associated odors influence odor preference and may serve as social cues.^[6][7] In 2008, Peter Donnelly and colleagues proposed that MHC is related to mating choice in some human populations.^[8]

Complementarity in social psychology is defined on the basis of the interpersonal circle (Carson, 1969), according to which interpersonal behaviors fall on a circle with two dimensions, namely dominance (i.e. dominant–submissive) and warmth (i.e. hostile–friendly). It states that each interpersonal behavior invites certain responses of another interactant. The behavior and the response it invites are said to be complementary (Horowitz, Dryer, & Krasnoperova, 1997) when friendly behavior begets hostile behavior, and dominant behavior begets submissive behavior. When people fail to give the invited response, it is said to be a non-complementary interaction. If the first person's behavior invites a reaction from the second person that matches the second person's goals, then the second person is satisfied; otherwise, the second person is frustrated (Dryer & Horowitz, 1997).