Correlations between human mating partners: a comprehensive meta-analysis of 22 traits and raw data analysis of 133 traits in the UK Biobank

Abstract

Assortative mating (AM) occurs when the correlation for a trait between mates is larger than would be expected by chance. AM can increase the genetic and environmental variation of traits, can increase the prevalence of disorders in a population, and can bias estimates in genetically informed designs. In this study, we conducted the largest set of meta-analyses on human AM published to date. Across 22 traits, meta-analyzed correlations ranged from r = .08 to r = .58, with social attitude, substance use, and cognitive traits showing the highest correlations and personality, disorder, and biometrical traits generally yielding smaller but still positive and nominally significant (p < .05) correlations. We observed high between-study heterogeneity for most traits, which could have been the result of phenotypic measurement differences between samples and/or differences in the degree of AM across time or cultures.

International Cross-Temporal Meta-Analysis of Assortative Mating for Educational Attainment

“…This study replicates the prior literature, suggesting that assortative mating for education exists and is large in magnitude. However, the correlation found in this study (.66) is reasonably higher than the .55 correlation found in another meta-analysis ( Horwitz et al, 2022 ). This discrepancy is primarily because this meta-analysis used latent methods of measuring educational attainment as the reference group, which have higher correlations because they measure educational attainment more accurately.…”

“…The US Census and CPS were obtained from the supplemental material provided by economists who were studying assortative mating ( Eika et al, 2019 ). In addition, academic literature that assessed assortative mating for education was gathered from another meta-analysis ( Horwitz et al, 2022 ). Studies that assessed samples that were not representative of their host country (e.g., individual provinces or states) were excluded from the meta-analysis.…”

“…Evidence from a meta-analysis indicates that partners are more similar to each other in the vast majority of personal characteristics than would be expected by chance ( Horwitz et al, 2022 ; McPherson et al, 2001 ). Some counterexamples include gender, chronotype, worrying, hearing difficulty, and irritability, which have a negative phenotypic similarity among partners.…”

Conventional twin studies overestimate the environmental differences between families relevant to educational attainment

“…EA is known to exhibit some of the highest spousal correlations for any trait investigated, averaging r=0.53. 25 However, phenotypic assortment is not the only possible explanation.…”

Sleeping with the enemy. Partners’ political attitudes and risk of separation

“…In increasingly divided times (see e.g., Layman et al 2006, Duffy et al 2019, Hobolt et al 2021, PEW Research 2014, 2019, it is important to understand how politics and union dissolution intersect. Several recent studies have considered partners' mating in terms of political ideology or preferences (e.g., Alford et al 2011;Hersh and Ghitza 2018;Horwitz and Keller 2022), but no study has examined the consequence of partners' political heterogamy on union dissolution. This is unfortunate given the important role that politics has in people's life.…”