U.S. high schools colored by the likelihood that someone attending the high school ends up marrying someone from that same high school. Blue means less likely, red means very likely.

It's a small romantic world after all.

At least that's what the number crunchers on Facebook's data science team discovered when analyzing anonymous data of U.S. couples over the age of 21 who classify themselves as "married" and also include the names of the high schools and colleges they attended in their profiles on the social network.

According to the results, 15% of couples on Facebook attended the same high school and 28% attended the same college. Some couples went to both the same high school and college, but the study controlled for that by only counting the first school they each attended together in the results.

The results showed that couples who attended high school in rural as opposed to urban areas were more likely to marry someone from the same school. Smaller, more conservative and religious colleges tended to have a higher likelihood of married graduates than other schools. For example, the study found that more than half of Brigham Young University graduates on Facebook also had a spouse who attended the school.