It’s been long believed that couples tend to look more alike over time, but a new study shows this isn’t exactly true.

Stanford University researchers say people tend to choose partners who have the same features as they do, just as they choose a partner with similar values and personality traits. The scientists write, “Spouses’ faces are similar but do not converge with time. This brings facial appearance in line with other traits—such as interests, personality, intelligence, values, and well-being—which show initial similarity but do not converge over time.”