Dec. 8, 2015 -- Men may have a better sense of direction than women because of their hormones, Norwegian scientists say.
They came to their conclusion by giving men and women route-mapping tasks, and then seeing if a small dose of testosterone ”helped” the women's performances.
In a lab, the participants donned 3-D goggles and steered with a joystick to complete tasks that involved finding their way between two points on a virtual maze. And they were up against the clock.
The researchers viewed the men and women's brains with a real-time MRI scanner during the exercise.
Different Navigation Strategies
In the first tests involving 18 men and 18 women, "men's sense of direction was more effective,” says Carl Pintzka, from the Norwegian University of Science and Technology. “They quite simply got to their destination faster."
Although men solved 50% more of the tasks than the women, different tactics for navigating emerged.
Men used the points of the compass more than women did, Pintzka says. "If they're going to the Student Society building in Trondheim, for example, men usually go in the general direction where it's located. Women usually orient themselves along a route to get there, for example, 'Go past the hairdresser and then up the street and turn right after the store.’"
Overall, using the main compass points is more efficient because it's more flexible, he says. This strategy is less dependent on where you set off from.
The real-time MRI images showed some differences in areas of the brain used by men and women while navigating.
The guys were more likely to use the part called the hippocampus, while women used frontal areas of the brain more.
"That's in sync with the fact that the hippocampus is necessary to make use of cardinal directions" using north, south, east, and west, Pintzka says.
He says evolution has played a role in the gender differences: "In ancient times, men were hunters and women were gatherers. Therefore, our brains probably evolved differently. For instance, other researchers have documented that women are better at finding objects locally than men. In simple terms, women are faster at finding things in the house, and men are faster at finding the house."
In a second series of tests, some women were given a small dose (0.5 mg) of testosterone dissolved under their tongue. The researchers found that several members of this group were able to orient themselves better in the four main north, south, east, and west directions.
A group of 42 women was then divided in two, and the groups were randomly given the hormone or a placebo (fake) treatment. Neither the women nor the researchers knew who got which doses.
"We hoped that they would be able to solve more tasks, but they didn't. But they had improved knowledge of the layout of the maze. And they used the hippocampus to a greater extent, which tends to be used more by men for navigating," Pintzka says.
He says the findings may help us understand some symptoms of Alzheimer's disease, where losing the sense of direction can be an early sign.
"Almost all brain-related diseases are different in men and women, either in the number of affected individuals or in severity. Therefore, something is likely protecting or harming people of one sex. Since we know that twice as many women as men are diagnosed with Alzheimer's disease, there might be something related to sex hormones that is harmful," he says.
The researchers say fluctuating female hormones during the women's menstrual cycles may have affected the results. Some women may think having the navigation tests designed by a man may have played a role.