Most people would think if it's not good looks that make a man most attractive to women, then it's definitely a sense of humor.

But studies show that altruism is actually a quality women are especially drawn to when they are looking for a relationship.

One study, published in January 2016 in the journal Evolutionary Psychology, presented 202 women with different men to choose from. The different combinations of choices were either attractive or not, and they either did a good deed or didn't.

The women chose the selfish, attractive men for a one-night stand. But for a long-term relationship, they chose the altruistic man whether he was attractive or not.

Another study, published in Social Psychological and Personality Science in July 2015, analyzed Germans' responses to a large annual survey.

Single people who reported doing good deeds were much more likely to say they were in a relationship the next year. They also found a partner in less time than their nonaltruistic peers.

That's not to say other traits don't matter. Humor is also important to women selecting a mate, researchers have found. It makes women assume a man is more intelligent.

A sense of humor is a good indicator of sexual activity, too. In one study, men who women rated as funnier reported having more sex with more partners.

For building long-term relationships, though, altruism is consistently found to be a crucial and highly desirable trait.

Another study, published in The Journal of Social Psychology in 2013, found that women valued altruism above other traits as a measure of whether a potential mate would make a good parent. They also said altruism was important for short-term relationships, but significantly more women said the trait mattered for the long-term.

Researchers have yet to pin humor head-to-head against altruism. It's also important to keep in mind that many of these studies are small, and that people often behave differently in real life than they do in a lab setting, or when responding to a survey.

But no matter what, if you're a man seeking a woman — especially for a long-term partnership — helping others can't hurt.