Cooperation, the cornerstone of all successful relationships, is an important societal issue. Cooperation between family members, friends, co-workers and even governments worldwide is something that is invaluable and instrumental. That said, men and women experience cooperation differently.

For example, a woman emerges from a department store fitting room and asks her husband what he thinks of a potential new dress. He nods his approval, hoping his time at the mall is nearing an end. So does the woman head straight to the cash register and make the purchase? Probably not.

Chances are her husband's enthusiasm won't be enough; she'll want to try on a few more dresses first.

Social psychology literature on cooperation tells us women generally tend to cooperate more, while men often try to avoid conflict. Thus, men might be subconsciously syncing their emotions with their partners during cooperation in an effort to reach a speedy resolution.

In a new study published in the journal Nature, researchers asked people to cooperate with a partner, then tracked the brain activity of both participants. They found males and females had different patterns of shared brain activity, according to lead authors Joseph Baker, Ph.D., a postdoctoral scholar at Stanford, and research associate Ning Liu, Ph.D.

Previous behavioral studies have found women cooperate more when they are being watched by other women. Men tend to cooperate better in large groups. And although a pair of men might cooperate better than a pair of women, in a mixed-sex pair the woman tends to be more cooperative.

To determine how cooperation is reflected in the brains of men and women who are actively cooperating — rather than just thinking about cooperating while lying in a machine — the Stanford researchers turned to a technique called hyperscanning, which involves simultaneously recording the activity in two people's brains while they interact.

Magnetic resonance imaging (MRI) requires participants to lie perfectly still and flat, so the scientists used near-infrared spectroscopy (NIRS), in which probes are attached to a person's head to record brain function, allowing them to sit upright and interact more naturally.

The 222 participants in the study were each assigned a partner. Pairs consisted of two males, two females or a male and a female. Then, while wearing the NIRS probes, each person sat in front a computer, across the table from their partner.

Partners could see each other but were instructed not to talk. Instead, they were asked to press a button when a circle on the computer screen changed color. The goal: to press the button simultaneously with their partner. After each try, the pair was told who had pressed the button sooner and how much sooner. They had 40 tries to get their timing as close as possible.

The researchers noted that on average, male-male pairs performed better than female-female pairs at timing their button pushes more closely. However, the brain activity in both same-sex pairs was highly synchronized during the activity, meaning they had high levels of "interbrain coherence."

According to Baker, within same-sex pairs, increased coherence was correlated with better performance on the cooperation task, yet the location of coherence differed between male-male and female-female pairs.

Surprisingly, male-female pairs did as well as male-male pairs at the cooperation task, even though they didn't show coherence. Because the brains of males and females showed different patterns of activity during the exercise, more research might shed light on how sex-related differences in the brain inform cooperation strategy — at least when it comes to this particular type of cooperation.

According to Baker, the study was exploratory and didn't probe cooperation in all manifestations. It could be that are other cooperative tasks in which female-female pairs do better than male pairs. And the researchers noted they hadn't measured activity in all parts of the brain for interbrain coherence.

However, the new findings could offer some clues into how cooperative behavior may have evolved differently between males and females and could eventually help researchers develop new ways to enhance cooperative behavior.