You have probably heard on numerous occasions that opposites attract.  It is an interesting idea, because it would suggest that tall people are attracted to short people, happy people are attracted to sad people and so forth.  This is relatively easy to check out and one of the interesting ways of tackling this question relates to what is called “Assortative Mating” – or who marries whom.

If you measure a range of characteristics in married couples you find that people tend, on average, to marry people who are similar to themselves.

For physical characteristics such as height or weight the correlations are moderate – 0.2 or less, depending on the characteristic, although Jared Diamond  observed in his wonderful book “The third chimpanzee” that the correlation between middle finger lengths of married couples was 0.61.  For those who are not familiar with correlations, positive correlations can range between 0 and 1 and a correlation of 0.61 is unusually high in human characteristics.  It means that if the husband has a middle finger markedly longer than average, there is a 36% probability that the wife will also have a long middle finger.  This suggests that when we meet potential partners we are probably unknowingly checking out physical characteristics which affect how we feel about them.  Interestingly, the same goes for earlobe length.

There are also strong correlations between the following in married couples:

  • Political beliefs – some studies put this as high as a correlation of 0.9.  This suggests that whilst it is not impossible that a communist will marry a member of the Palmer United Party, but it is likely to be rather rare.
  • Socioeconomic status – middle class people tend to marry middle class people.
  • Physical attractiveness – correlations in excess of 0.48 in some studies, so attractive people tend on average to marry attractive people.  Yes, I know that there are exceptions, but this is a significant correlation over large numbers of couples.
  • Intelligence – 0.4 – smart people tend to marry smart people.
  • Personality – 0.4 – introverts tend to marry introverts, etc.

So, opposites don’t attract, we are attracted to people we are similar to.  This also applies to the workplace.  A consistently identified characteristic of human personality is “emotionality” sometimes measured as “neuroticism”.  This is the tendency to be either emotionally stable or emotionally unstable.  I’m sure you know some people who are extremely emotionally stable – nothing upsets them.  You also know people who are highly emotional and easily upset.  Have you ever noticed that emotionally stable, resilient people tend to seek each other out?  The same goes for emotionally unstable, easily upset people who tend to gather together in pockets of negativity and tell each other how bad everything is.  This can be a very big challenge in change management, as I am sure you have noticed.  Just one more reason to measure such characteristics before you hire.


Andrew Marty,
Managing Director
SACS Consulting



Diamond, JM, 1992 The Third Chimpanzee: The Evolution and Future of the Human AnimalISBN 0-06-098403-1

Assortative mating for perceived facial personality traits Anthony C. Little a,*, D. Michael Burt b , David I. Perrett c a School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK b Department of Psychology, University of Durham, Science site, Durham, DH1 3LE, UK c School of Psychology, University of St Andrews, St Marys College, St Andrews, KY16 9JP, UK Received 9 August 2005; received in revised form 23 September 2005;

Andrew Marty