Media playback is unsupported on your device Media caption The video game that's actually dementia research

Men are better at navigating than women, according to a massive study, but there's not much for men to be proud about.

Scientists at University College London say the difference has more to do with discrimination and unequal opportunities than any innate ability.

The findings come from research into a test for dementia.

But it has also given an unprecedented insight into people's navigational ability all around the world.

The experiment is actually a computer game, Sea Hero Quest, that has had more than four million players.

It's a nautical adventure to save an old sailor's lost memories and with a touch of a smartphone screen, you chart a course round desert islands and icy oceans.

Image copyright UCL

The game anonymously records the player's sense of direction and navigational ability.

One clear picture, published in the journal Current Biology, was that men were better at navigating than women. But why?

Prof Hugo Spiers thinks he has found the answer by looking at data from the World Economic Forum's Gender Gap Index - which studies equality in areas from education to health and jobs to politics.

He told the BBC: "We don't think the effects we see are innate.

"So countries where there is high equality between men and women, the difference between men and women is very small on our spatial navigation test.

"But when there's high inequality the difference between men and women is much bigger. And that suggests the culture people are living in has an effect on their cognitive abilities."

Sea Hero Quest has produced a raft of other findings.

Denmark, Finland and Norway have the world's best navigational skills - possibly down to their "Viking blood"

Sense of direction is in constant decline after you emerge from your teenage years

People in wealthier countries also tend to be the best navigators

Image copyright UCL Image caption The deeper the colour, the stronger the country's navigational ability

The popularity of the game has turned it into the world's biggest dementia research experiment.

Being lost or disoriented is one of the first signs of the disease.

The next step in the research is to see if catching sudden declines in navigational ability could be used to test for dementia.

Tim Parry, the director of Alzheimer's Research UK, said: "The data from Sea Hero Quest is providing an unparalleled benchmark for how human navigation varies and changes across age, location and other factors.

"This really is only the beginning of what we might learn about navigation from this powerful analysis."

This project was funded by Deutsche Telekom and the game was designed by Glitchers.

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