He has published on the topics of breakup, geographic separation, infidelity, social networks, cognition, and need fulfillment and emotions in relationships.
This is old science from when women relied on men financially.
However, it doesn’t represent women’s preferences at all.
So maybe there is a kernel of truth the rule, at least for men. Le's research focuses on commitment, including the factors associated with commitment and its role in promoting maintenance.
According to this rule, it would not be creepy for a 30 year old to date a 22 year-old, but an 18 year-old would be off-limits.Men, in contrast, are hypothesized to be most attracted to women in their reproductive prime, which tends to be when they are younger. Women’s preferences, on the other hand, hold relatively constant across their lives, not going more than a few years below their own age (extra-credit if you can identify the "cougar zone" in this figure), but women remain keen on men up to 10 years older than themselves. However, younger men (i.e., in their 20’s) tend to be married to someone of a similar age, but as they get older their wives get younger.For example, by their 50’s the average male has a wife who is 10 years younger than him. I don't know why this one year made such a difference to me. After spending a few days trying to adjust to the fact that the handsome co-leader of my small group was seven years my junior, I had just realized that he was actually eight years younger!