relationships

The rules of attraction might drive our initial decisions, for better or worse. But lasting relationships are about much more than what we see and smell.
Behavior plays a key role, with biology an intriguing contributing factor.
One of the oldest theories about attraction is that like begets like. It explains that eerie perception that married couples sometimes look awfully similar.

Last year, J. Philippe Rushton, a psychologist at the University of Western Ontario, looked into the relationships of people's genes. Based on a set of heritable personality traits, having similar genetics plays 34 percent of the role in friendship and mate selection, he found.
"The main theory is that some genes work well in combination with each other," Rushton told LiveScience. "If these genes evolved to work in combination, then you don't want to break that up too much for your offspring. Finding a mate with similar genes will help you ensure this."
If your spouse is genetically similar, you're more likely to have a happy marriage, for example. Child abuse rates are lower when similarity is high, and you'll also be more altruistic and willing to sacrifice more for someone who is more genetically like you, research shows.
It probably comes as little surprise people are drawn to individuals with similar attitudes and values, as psychologist Eva Klohnen at the University of Iowa found in a 2005 study of newlywed couples. These characteristics are highly visible and accessible to others and can play a role in initial attraction.
When it comes to sticking together for the long haul, researchers have shown that likeness of personality, which can take more time to realize, means more.
Comedy can also help a relationship. But the importance of humor is different for men and women, says Eric Bressler of McMaster University.
A woman is attracted to a man who makes her laugh, Bressler found in a 2005 study. A man likes a woman who laughs at his jokes.