Do we marry people because of their last name?

People with the same last name are much more likely to marry each other.

Via Subliminal: How Your Unconscious Mind Rules Your Behavior:

The source of love has been pondered for eons by lovers, poets, and philosophers, but it is probably safe to say that none of them has ever waxed eloquent about this particular factor: the person’s name. This table, however, shows that a person’s name can subtly influence your heart— if the name matches your own.

Listed along the horizontal and vertical axes are the five most common U.S. surnames. The numbers in the table represent how many marriages occurred between a bride and a groom with the corresponding names. Note that the largest numbers, by far, occur along the diagonal— that is, Smiths marry other Smiths three to five times as often as they marry Johnsons, Williamses, Joneses, or Browns. In fact, Smiths marry other Smiths about as often as they marry people with all those other names, combined. And the Johnsons, Williamses, Joneses, and Browns behave similarly. What makes the effect even more striking is that these are the raw numbers— that is, since there are almost twice as many Smiths as Browns, if all else were equal, you’d expect Browns to marry the ubiquitous Smiths far more often than the rarer Browns— but even so, by far the greatest number of marriages among Browns is to other Browns.

What does this tell us? People have a basic desire to feel good about themselves, and we therefore have a tendency to be unconsciously biased in favor of traits similar to our own, even such seemingly meaningless traits as our names. Scientists have even identified a discrete area of the brain, called the dorsal striatum, as the structure that mediates much of this bias.

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