The old adage that ‘opposites attract’ is a myth – because in real life people seek out others who are just like them, new research suggests.
Similarity is actually the key to a long lasting romance , or friendship, and it is hard wired into our brains, say scientists.
The finding could lead to a fundamental change in understanding affairs of the heart – and also sounds a warning for the idea that couples can change each other over time.
In the largest study of its kind psychologists looked at romantic couples, friends and acquaintances and compared attitudes, values, prejudices, personality traits or behaviours important to them.
It showed, contrary to popular belief, future partners or partners are already alike at the outset.
Prof Angela Bahns, of Wellesley College , Massachusetts, said: “Picture two strangers striking up a conversation on a plane, or a couple on a blind date.
“From the very first moments of awkward banter, how similar the two people are is immediately and powerfully playing a role in future interactions.
“Will they connect? Or walk away? Those early recognitions of similarity are really consequential in that decision.”
Whether or not a relationship develops could depend on the level of similarity the two individuals share from the beginning of their meeting.
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Prof Chris Crandall, of the University of Kansas, said: “You try to create a social world where you are comfortable, where you succeed, where you have people you can trust and with whom you can cooperate to meet your goals.
“To create this, similarity is very useful, and people are attracted to it most of the time.”
Prof Bahns said the research published in the Journal of Personality and Social Psychology, has identified friends show very little change in personality, attitudes and values, and a selection of socially-relevant behaviours.”
The data also suggests our drive to select like minded others may be far stronger than previously assumed.
Prof Bahns said: “We are arguing selecting similar others as relationship partners is extremely common – so common and so widespread on so many dimensions it could be described as a psychological default.”
The researchers added people are not seeking shared similarity on one or two particular topics, but are more similar than chance on almost everything measured, and especially so on the things that matter most to them.
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They used data from a field research method dubbed “free range dyad harvesting,”to see how similar or different the pairs were, and to test whether those who had known each other longer and whose relationships were closer and more intimate were more similar. They were not.
The researchers also surveyed pairs who had just met in a college classroom setting, and then surveyed them later over time.
Prof Crandall said: “In a smaller study that led up to this one, we looked at students at KU (Kansas University), a big state university, and several smaller colleges in western and central Kansas.
“At KU, people found people who were more similar to themselves than at small colleges, where there just are not as many choices in friends.
“At small colleges friends were less similar – but just as close and satisfied, and spent the same amount of time together.
“We know people pick similar people at first, but if you go out of your way you can find excellent friends, and meaningful relationships, with people who are different.”
Prof Bahns said the study could be a “cautionary message” for those who think they can change their friends or romantic partners.
She said: “Change is difficult and unlikely. It is easier to select people who are compatible with your needs and goals from the beginning.”
The quest for similarity in friends could result in a lack of exposure to other ideas, values and perspectives.
Prof Crandall said: “Getting along with people who are not like you is really useful.
“Friends are for comfort, taking it easy, relaxing, not being challenged – and those are good things. But you cannot have only that need.
“You also need new ideas, people to correct you when you are loony. If you hang out only with people who are loony like you, you can be out of touch with the big, beautiful diverse world.”
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Prof Wendy Mendes, the Sarlo/Ekman chair in the study of human emotion at the University of California, San Francisco, said: “This research offers one of the most definitive accounts showing not only do ‘birds of a feather flock together’ but goes one step further to show ‘birds of a feather find each other before flocking.'”