Differences in dating
Early on in a relationship, both partners put their best foot forward, showing off the most pleasant, polished versions of themselves.
In addition, Buss collected actual age differences at marriage for 27 of the 37 cultures, and across the board men normally married women who were younger than themselves.
As people get older, age difference means less and less.
Obviously, a 40-year-old marrying a 20-year-old will be questioned, while no one will think twice about an 80-year-old marrying a 60-year-old.
That is, men gave lower ratings to dates where the man was older.
Likewise, women also rated the dates lower when the man was older than the woman.