Does living with someone for a long time change you?

Very much. And not at all.

Happy same-age couple, from Midjourney

This post is mostly about adult couples, about how people who love each other and live together for a long time influence one another.

But I want to bookend the discussion with a different question about children. (It’ll become clear pretty quickly how the questions are related.)

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Do parents influence the kind of person a child grows up to be? Put differently, does parenting matter?

People differ in all sorts of ways—intelligence, personality, sexual orientation, political orientation, how religious we are, how much schooling we end up with, whether we suffer from mental illness, whether we abuse alcohol and other drugs, and so on. One explanation for these differences is genetic. Because you share your biological parents’ genes, you resemble them in all sorts of ways, physical and psychological, even if you never meet them—even if you were adopted and raised by other people.

You might think that another factor is parenting. It makes sense that your intelligence and personality, for instance, are affected by whether Mom and Dad read books to you and took you to museums or discouraged you from any intellectual pursuit; whether they were emotionally cold or showered you with love.

You might be surprised, then, to hear that many psychologists think common sense is wrong here. Their answer to “Do parents matter?” is “Yes, but only because they pass on their genes.”

I won’t review the argument for the “Parenting doesn’t matter” side here. (Stay tuned for another post or read the sources cited in this footnote.)¹ But here’s a counter-argument that has always made a lot of sense to me.²

Parenting has to have an effect. Children live with their parents for a very long time in close contact. Shouldn’t this have a big effect on the sorts of people they become, just because living with anyone for so long will have a big effect on a person?

Maybe it doesn’t show up in IQ tests or personality tests, but there are a million ways people living together influence one another. Why should the relationship between children and parents be an exception to this?

Let’s forget about children for a moment. Suppose you married at 30 and are now together at 50. If you are like most couples, during these twenty years together, you have spent a lot of time together, more so than with anyone else, except possibly your children. Shouldn’t all this contact with this other person have a profound effect?

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Answer 1: Yes—who you live with changes you a lot