A study found that similarity is more prevalent in romantic relationships. Partners are likely to share traits in 82-89% of instances.
A recent study conducted by researchers at the University of Colorado Boulder has challenged the long-held belief that “opposites attract.” The study, which analyzed over 130 traits and included millions of couples over the past century, found that partners are more likely to be similar than different in 82-89% of cases. This finding has important implications for understanding human relationships and for genetic research.
The study’s findings suggest that individuals are more likely to form lasting relationships with those who share similar values, beliefs, and lifestyles. This is likely due to the fact that couples who are more alike tend to have a stronger foundation of shared interests and experiences. Additionally, similarities can lead to greater understanding and empathy between partners, which can further strengthen the relationship.
While there may be some exceptions to this rule, the overall trend suggests that similarity is a key factor in successful relationships. This is important for health-conscious individuals to consider, as strong relationships can have a positive impact on overall well-being.
The study analyzed 22 traits across 199 studies involving millions of couples, as well as 133 traits across almost 80,000 opposite-sex pairs in the UK Biobank.
- Political and religious attitudes
Partners were highly likely to share similar political and religious views, with a correlation of 0.58.
- Substance use habits
Partners with similar substance use habits, such as heavy smoking, heavy drinking, or complete abstinence, tended to pair up.
- Health-related traits
Traits like height, weight, and medical conditions also showed positive correlations among partners.
- Personality traits
While personality traits exhibited lower correlations, some, such as neuroticism, still showed a degree of similarity.
Contrary to popular belief, there was no significant correlation between extroversion and partner extroversion.
When Birds of a Feather Don’t Flock Together
While the study revealed a strong tendency for partners to share similar traits, there were a few instances where opposites seemed to attract, albeit to a limited extent.
In the UK Biobank sample, a small negative correlation was observed for traits such as chronotype (morning lark versus night owl), tendency to worry, and hearing difficulty. Further research is needed to fully understand these findings.
Interestingly, the trait for which couples were most likely to be similar was birth year, suggesting that shared age could play a role in partner selection.
Even uncommon traits, such as number of sexual partners and breastfeeding history, exhibited some degree of correlation, indicating that shared life experiences may influence mate choice.
These findings suggest that underlying mechanisms, often beyond our conscious awareness, may influence our romantic decisions.
Understanding Assortative Mating
The study revealed that couples tend to share similar traits, including health-related characteristics, due to various factors such as shared environment, initial attraction, and long-term relationship dynamics.
While these correlations may seem modest, they could have significant implications for future generations. For instance, if individuals with similar health habits partner up, their offspring may be more predisposed to certain health conditions.
Similarly, assortative mating patterns in educational backgrounds could exacerbate socioeconomic disparities.
The findings also highlight the importance of understanding the nuances of assortative mating, as it has been misused in the past to promote harmful agendas.
This research serves as a springboard for further exploration across various disciplines, potentially leading to a deeper understanding of relationship dynamics and their impact on individuals and society at large.
Positive correlations between mates can increase trait variation and prevalence, as well as bias estimates from genetically informed study designs. While past studies of similarity between human mating partners have largely found evidence of positive correlations, to our knowledge, no formal meta-analysis has examined human partner correlations across multiple categories of traits. Thus, we conducted systematic reviews and random-effects meta-analyses of human male–female partner correlations across 22 traits commonly studied by psychologists, economists, sociologists, anthropologists, epidemiologists and geneticists. Using ScienceDirect, PubMed and Google Scholar, we incorporated 480 partner correlations from 199 peer-reviewed studies of co-parents, engaged pairs, married pairs and/or cohabitating pairs that were published on or before 16 August 2022. We also calculated 133 trait correlations using up to 79,074 male–female couples in the UK Biobank (UKB). Estimates of the 22 mean meta-analysed correlations ranged from rmeta = 0.08 (adjusted 95% CI = 0.03, 0.13) for extraversion to rmeta = 0.58 (adjusted 95% CI = 0.50, 0.64) for political values, with funnel plots showing little evidence of publication bias across traits. The 133 UKB correlations ranged from rUKB = −0.18 (adjusted 95% CI = −0.20, −0.16) for chronotype (being a ‘morning’ or ‘evening’ person) to rUKB = 0.87 (adjusted 95% CI = 0.86, 0.87) for birth year. Across analyses, political and religious attitudes, educational attainment and some substance use traits showed the highest correlations, while psychological (that is, psychiatric/personality) and anthropometric traits generally yielded lower but positive correlations. We observed high levels of between-sample heterogeneity for most meta-analysed traits, probably because of both systematic differences between samples and true differences in partner correlations across populations.