Image caption The sights and sounds of the city have a negative impact on the ability to focus

Cities really do disrupt people's ability to concentrate, suggests research.

Researchers from Goldsmiths, University of London have studied a remote tribe in Africa - where some people have remained in the countryside while others have moved to urban areas.

It found the urbanised group found it much harder to focus their attention.

Researcher Karina Linnell says the difference in powers of concentration was much greater than expected.

It might also confirm the worst fears of all the caffeine-fuelled office workers trying to multi-task.

Dr Linnell, from the university's psychology department, carried out cognitive tests with the Himba tribe in Namibia in south west Africa - and also included a further comparison with young people in London.

She found that the Himba tribesmen and women who had stayed in a rural, cattle-herding setting were much better at tests requiring concentration than members of the same tribe who had been urbanised and were living in towns and cities.

Bright lights, big city

The results for urbanised Himba were "indistinguishable" from the results of undergraduates taking the same tests in London, said Dr Linnell.

The researchers suggest that people in an urban setting have too much stimulation, with an overload of sights and sounds competing for attention.

Image caption The rural Himba people were much better at concentrating than the city dwellers Pic: WG

Concentration is improved when people's senses are aroused, says Dr Linnell, but if this becomes excessive it seems to have the opposite effect and reduces the ability to focus on a single task.

As such the people living in cities were not as good at tests which required sustained focus and the ability not to be distracted.

The rural living people were much better at such tests of concentration, even computer-based tasks, where they might have been expected to be less familiar with the technology.

This is not necessarily a case of being better or worse, says Dr Linnell, but it could be a reflection of what is needed to survive in an overcrowded urban setting.

It is also not a "fleeting" impact, she suggests, as the tests show that urbanised people from this tribe have developed a different way of looking at events.

"There are really quite profound differences as a function of how we live our lives," she says.

Another finding is that the Himba people who have moved to the city are more likely to be dissatisfied and show signs of unhappiness.

In contrast the simpler, frugal life of the rural tribespeople seems to leave them with a greater sense of contentment.

When so many of the world's population are now living in urban settings this has far-reaching significance, says Dr Linnell.

It could mean that many urban dwellers are performing below their capacity when it comes to tasks requiring sustained thinking.

"What if, for example, companies realised certain tasks would be better carried out by employees based outside of the urban environment where their concentration ability is better?" she says.

Dr Linnell also suggests that this urban disruption of concentration could be linked to a reduction in attention spans.