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Bad driving 'linked to hormones'

Spatial skills such as map reading and parking may be difficult for some women because they had too little testosterone in the womb.

Some men have long held that women are deficient in these skills.

Scientists from the University of Giessen, Germany, writing in the journal Intelligence found a lack of the hormone affects spatial ability.

Low testosterone levels are also linked to shorter wedding ring fingers, they say.

The research looked at the spatial, numerical and verbal skills of 40 student volunteers.

Men do seem to be better at spatial abilities, and women at verbal and emotional skills

Dr Nick Neave, British Psychological Society

Spatial skill is the ability to assess and orientate shapes and spaces. Map reading and parking are spatial skills which men often say women lack. Women tend to disagree.

The researchers also looked at the length of the students' wedding and index fingers.

In women, the two fingers are usually almost equal in length, as measured from the crease nearest the palm to the fingertip. In men, the ring finger tends to be much longer than the index.

For one of the spatial tests, volunteers had to tell which of five drawings could not be rotated so it looked like the other four.

The other test involved the ability to think in 3D by mentally "unfolding" a complex shape.

Overall, men achieved higher scores in the tests than women.

But women with the male pattern of finger length did better than those whose wedding finger was shorter.

They also scored better on the numerical tests.

Fertility

Writing in Intelligence, the researchers, led by Dr Petra Kempel, said women who had 'male-like' finger length ratio patterns outperformed other women.

They added that the differences seen within the group studied were "remarkable."

However, the researchers accept that their study was limited because only one saliva sample was taken from each person, and no detailed account was taken of women's menstrual cycle, which can affect hormone balance.

Other studies looking at finger length ratio have suggested that, in men a long ring finger and symmetrical hands are an indication of fertility, and that women are more likely to be fertile if they have a longer index finger.

Another study controversially suggested that finger length ratio could also be linked to sexual orientation, with lesbian women having a greater difference in length between their ring finger and index finger than straight women do.

Dr Nick Neave, an evolutionary psychologist at the University of Northumbria who specialises in spatial awareness and gender differences.

He said: "Being exposed to testosterone early on does seem to affect the way the brain works.

"It seems to push it to work in a more masculine way, with a stronger right hemisphere; the spatial hemisphere.

"The extra testosterone also appears to cause the ring finger to be longer than the index."

Bones contain testosterone receptors, and Dr Neave said the fourth finger appeared to be particularly receptive to levels of the hormone.

Higher levels are linked the ring finger being longer than the index.

Dr Neave, a member of the British Psychological Society, added: "The sexes do use different skills to find their way around. Men seem to be able to keep the route in their head without landmarks, whereas women do use them.

"So men may be better at finding the car when its parked in a huge shopping centre car-park. It may also tap into driving and parking abilities."

He added: "Men do seem to be better at spatial abilities, and women at verbal and emotional skills.

"It may be a generalisation, but that does seem to be the case."

But Dr David Gray of the Department of Philosophy at Harvard University, said: "Correlation between genetic features and skills may often have an environmental intermediary which determines performance at a given skill."

He suggested skilled drivers may be those who are more practised at the activity. In addition, he said people with longer ring fingers may have dominating personalities and therefore do more driving.

"This practice would make them better at these activities and would be correlated with a physical feature, but not caused by it."

http://news.bbc.co.uk/1/hi/health/4202199.stm