(CNN) - Online daters tend to pursue users who are roughly 25% "more desirable" than they are -- and, by the looks of their messages, many are well aware of the "hierarchy," according to a study published Wednesdayin the journal Science Advances.

The study found that the higher up we reach, the longer our messages tend to get -- and the less likely we'll get a message back.

"We have this phrase 'you're out of my league.' What does it mean scientifically for someone to be out of your league? ... How can we figure out who's in and who's out?" said study author Elizabeth Bruch, associate professor​ of complex systems and sociology at the University of Michigan.

"Intuitively, I expected to find some sort of desirability gap," she said, "but I was thinking more on the order of 5 or 10%, not 25%. That number for me was really striking."

The data come from nearly 187,000 heterosexual daters on a "popular, free online dating service" in New York, Chicago, Seattle and Boston, according to the study. The researchers did not name the dating service due to a nondisclosure agreement they signed with the company, Bruch said.

 

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