Psychology In The News | Opposites Don't Attract

A new study published in the journal Nature Human Behaviour suggests that romantic partners tend to be very similar, sharing up to 89% of their traits. In the largest study yet of human partner preferences, Horwitz et al (2023) conducted a meta-analysis encompassing 8 million couples across 199 previous studies, as well as analysing self-report data from nearly 80,000 couples in the UK Biobank database. All the couples studied were in male-female pairs.

The researchers examined similarity across 133 different traits including personality, political values, drinking, and substance use habits, age at which each partner became sexually active and level of education.

To analyse the data, researchers correlated the similarity between couples using a combination of inferential tests including Pearson’s r and Spearman’s rho. Correlation coefficients were then calculated for the degree of similarity for 133 traits. For example, a correlation of +0.58 was found for political values across the meta-analysis. Furthermore, there was a correlation of +0.87 for birth year from the UK biobank part of the study. Religion and level of education had a correlation of +0.6. Negative health behaviours were also positively correlated with drinking alcohol to excess being +0.28 and smoking +0.5. Only a handful of traits, like being a morning versus night person or tending to worry, showed dissimilarity between partners.

This study provides support for assortative mating theory which is the idea that people subconsciously seek out and select partners who are like themselves. This similarity filtering may reinforce socioeconomic divides and contribute to the heightening of extreme traits across generations. For example, if both parents have a psychiatric disorder this could increase the chance that their children inherit this. Furthermore, when people with similar levels of education (and often wealth) form relationships together, the socioeconomic divide may deepen. Choosing who you wish to spend your life with is a very personal decision, with wide-ranging consequences for society.

ANSWER THE FOLLOWING QUESTIONS!

1. This study focused on male-female pairs only. Why might this limit the external validity?
2. Considering your answer to the first question, how could you address this problem?
3. In this study, the researchers conducted a meta-analysis, what is a meta-analysis?
4. The UK biobank involves a self-report measure which asks participants about how much alcohol they drink, how much they smoke and their political views. What problem might arise when using a self-report measure to assess such variables?
5. Why would a researcher use a Spearman’s rho inferential test?
6. What does a correlation coefficient describes

References

1. Opposites Don’t Attract: Why You and Your Spouse Are So Much Alike https://time.com/6311685/study... (accessed 22.1.24)
2. Horwitz T, Balbona J, Paulich K, Keller M (2023) Correlations between human mating partners: a comprehensive meta-analysis of 22 traits and raw data analysis of 133 traits in the UK Biobank. Nature Human Behaviour, 7, pg 1568–1583