In evolutionary psychology, narcissism is considered in terms of the mechanisms that underlie assortative mating, which refers to the concept that the partners people choose for procreation is not random.
A large evidence base exists to support the concept of assortative mating, with humans having been observed to choose their partners based on factors that include age, height, weight, IQ, physical characteristics, personality traits, nationality, level of education, occupation and family relatedness.
One hypothesis, referred to as the “self seeking like” hypothesis suggests that people automatically and subconsciously seek a mate who is the mirror image of themselves and base their choices on the presence of attractive characteristics that they believe they themselves have.
According to a study by Liliana Alvarez and colleagues, facial resemblance between partners is a driving force behind assortative mating mechanisms, with human couples often resembling each other in terms of physical characteristic to a significantly greater degree than would be expected from randomly paired couples. As facial characteristics are generally inherited, the “self seeking like” process may attract mates that are genetically similar, therefore favoring the stabilization of genes that support social behavior, despite the absence of a familial relationship.
Some evolutionary psychologists believe that humans have certain physical and personality traits that have evolved to confer a reproductive advantage. These traits are referred to as “sexual ornaments.” These features are automatically assessed as indicators for the fitness of a potential mate and are believed to attract the attention of and evoke sexual desire in the person seeking a mate. The selection of a mate therefore depends on the presence or absence of these indicators of fitness, when compared to the competition. Narcissistic equilibrium is regulated to a significant degree by a person’s perception of their own reproductive fitness and survival.