A new study finds that agreeable workers earn significantly lower incomes than less agreeable ones. The gap is especially wide for men.

The researchers examined "agreeableness" using self-reported survey data and found that men who measured below average on agreeableness earned about 18% more—or $9,772 more annually in their sample—than nicer guys. Ruder women, meanwhile, earned about 5% or $1,828 more than their agreeable counterparts.