Psychological Trait Heritability on the Rise, Amplifying Mate Selection's Impact on Offspring

Recent advancements in scientific measurement and analytical methods are revealing an upward trend in the estimated heritability of key psychological traits, prompting renewed discussion on the profound implications of spouse selection. According to a recent social media post by "Keeper," a notable observer in the field, "As our measurements and analytical methods improve, the estimated heritabilities of key psychological traits keep increasing." This development highlights that "choosing the right spouse" is becoming "even more important, since you are also to a large extent choosing the traits of your future children.

This observed increase in heritability estimates is supported by extensive research. A systematic review and meta-analysis of 139 infant twin studies, encompassing nearly 80,000 twins, confirmed moderate to high genetic influences across a wide array of infant psychological traits and developmental milestones. Similarly, researchers at Yale School of Medicine have identified numerous new genetic sites linked to specific personality traits, further solidifying the genetic underpinnings of individual psychology.

The concept of "assortative mating," where individuals tend to pair with those sharing similar phenotypes or genotypes, is a well-documented phenomenon. Studies show that people often select partners who resemble them in various characteristics, including intelligence, personality traits, and socio-economic status. This non-random mating pattern has significant genetic and social consequences for families and future generations.

Assortative mating can lead to increased genetic relatedness within families and contribute to the intergenerational transmission of traits. A 2024 study in Nature Human Behaviour revealed that partners exhibit similarities in mental health even before they meet, and that educational attainment significantly influences mate selection. This suggests that the choices individuals make in partners can amplify existing traits and contribute to patterns of social and genetic inheritance.

The growing understanding of psychological heritability and assortative mating underscores the tweet's assertion regarding the long-term impact of partner choice. As scientific methods continue to refine our understanding of genetic contributions to human behavior, the decision of who to marry gains additional weight, extending beyond immediate compatibility to the inherited predispositions of future offspring.