Do Opposites Actually Attract?

Do opposites attract, or have we just been repeating that because it makes relationships sound more interesting?

You know the couple.

One talks to everybody at the party. The other wants to leave after twenty minutes.

One plans holidays six months ahead. The other books the hotel from the airport.

One is tidy. The other apparently believes chairs were invented to store clothes.

Someone eventually smiles and says, “Well, opposites attract.”

It feels true because differences are easy to notice.

Psychologists have now looked at the much bigger picture.

And the bigger picture says something considerably less romantic:

Most couples are more similar than different.

Do Opposites Attract? Researchers Actually Checked

In 2023, researchers at the University of Colorado Boulder published one of the largest attempts yet to test the idea.

First, they pulled together 199 previous studies looking at 22 characteristics in millions of couples. Some of that research went back as far as 1903.

Then they separately analysed 133 characteristics in almost 80,000 male-female couples from the UK Biobank.

Across the two analyses, partners were more likely to resemble each other on somewhere between 82% and 89% of the traits studied.

In only about 3% of traits, and only in one part of the analysis, did researchers find evidence that partners tended to be opposites. 

So if the question is simply do opposites attract, the best population-level answer is:

Mostly, no.

The Similarities Were Not Just Obvious Ones

Age was unsurprisingly one of the strongest similarities.

But couples also tended to match on things such as education, religious attitudes, political values and drinking or smoking habits.

Political values showed a fairly strong correlation in the researchers’ review. Education and some substance-use behaviours also showed substantial similarities between partners. 

Think about that for a moment.

You may believe you chose someone because they made you laugh, had nice eyes or happened to sit beside you at work.

But relationships do not begin in a vacuum.

People meet through universities, jobs, neighbourhoods, religions, friends and social circles. Those places already contain people who are more similar to one another than a random selection of humanity.

Your dating pool has been filtered before you even start dating.

But Couples Are Not Copies of Each Other

This is where the research gets more interesting.

Similarity was much weaker for many personality traits.

Take extroversion.

The idea that a loud extrovert naturally seeks out a quiet introvert sounds convincing. So does the opposite idea, that extroverts prefer other extroverts.

The researchers found very little evidence either way.

For extroversion, partner similarity was weak enough that the study’s lead author compared the outcome to something close to flipping a coin. Neuroticism also showed only a small positive relationship between partners. 

So “similar people get together” does not mean every happy couple has matching personalities.

You can disagree about music, socialising, tidiness, food and whether arriving twenty minutes early is sensible or deeply irritating.

The broader similarities may sit somewhere else.

Values.

Education.

Lifestyle.

Religion.

How much you drink.

What kind of future you imagine.

Those differences are not as funny at dinner parties, but they may matter more when two people actually build a life together.

Why Do Similar People End Up Together?

There is no single reason.

Sometimes people deliberately prefer someone like themselves.

Sometimes the environment does the sorting.

If you spend years in a particular profession, university, religious community or social class, you are simply more likely to meet people who share certain characteristics.

And sometimes couples may become more similar after getting together.

They live in the same house. Eat similar food. Share friends. Influence each other’s habits. Make financial decisions together.

A separate study of more than 51,000 couples found evidence that partner choice, shared circumstances and becoming more alike over time can all contribute to why couples resemble one another. 

So when two people look remarkably similar after twenty years together, it may be partly because they started that way and partly because twenty years together did some work.

Similarity Does Not Automatically Mean Happiness

There is another trap here.

If opposites do not usually attract, should you search for somebody exactly like yourself?

Not necessarily.

A 2023 study of 1,294 heterosexual couples looked specifically at personality similarity and relationship satisfaction.

Being more similar in personality was not reliably associated with being happier in the relationship. 

That is an important distinction.

The research on do opposites attract tells us something about who tends to pair up.

It does not give us a formula for who should stay together.

Two people can share political beliefs, education and drinking habits and still drive each other insane.

Two people can have very different personalities and have an excellent marriage.

Population patterns describe people.

They do not write individual love stories.

So Where Did “Opposites Attract” Come From?

Probably partly because opposites are memorable.

Nobody tells their friends:

“My wife and I both value education, have similar religious views and consume roughly comparable amounts of alcohol.”

That is not much of a story.

Instead:

“She talks to everyone. I hate parties.”

Now we have something.

Differences also become more visible when people spend years together. The thing your partner does differently is usually far more noticeable than the hundred assumptions you quietly share.

You notice that one of you squeezes the toothpaste incorrectly.

You rarely notice that both of you agree on where to live, whether to have children, how important work should be, what counts as wasting money and which things are worth arguing about.

Similarity is often invisible because it feels normal.

The Old Saying Probably Has It Backwards

So, do opposites attract?

Sometimes, absolutely.

Real relationships contain every possible combination of personalities.

But when researchers stop looking at memorable couples and start looking at millions of them, there is little evidence for opposites being the general rule.

On most of the things researchers measured, people were more likely to pair with someone similar.

There is another old saying that psychology seems to like better:

Birds of a feather flock together.

It is not nearly as romantic.

It just happens to be closer to the data.

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