A research in 1987 by Robert Zajonc, a psychologist from The University of Michigan, showed that long-married couples become more alike because they live in the same environment, thus imitating facial expressions, behavior, habits, and so on. Changes in facial expression are believed to affect and permanently change the shape of the muscles in the face gradually. This facial change is called facial homogony. However, this research only involved 12 couples, so the conclusions drawn were not completely reliable.
– .
