Being shy can shorten your life

It's good news for the risktakers . . . and a warning for shrinking violets.
Those who relish new challenges and change are likely to live longer than those who fear such hurdles.

The conclusions come from experiments on rats, but the researchers who conducted them are certain that similar physiological processes affect humans.

Scientists already know that people with a negative outlook on life fall ill more often, because their immune systems tend to be weaker and less able to fight off infection.

Now, it seems, the prognosis for the shy could be worse. Those of us plagued by a fear of anything new may be more likely to die early from cancer than less timid individuals.

Researchers found that rats they identified as 'neophobic' - frightened of new things - had a 60 per cent greater chance of dying at any given time than their confident counterparts.

They also produced a greater surge of stress hormones when placed in an 'exploration arena' containing unfamiliar objects.

An almost identical hormone response is seen in children who are shy, inhibited and fearful, and is detectable as early as 14 months.

Scientists Sonia Cavigelli and Martha McClintock, from the University of Chicago, measured the average difference in the lifespan of the rats at 102 days.

The American scientists wrote in the journal Proceedings of the National Academy of Sciences: 'This finding provides strong support for using the natural variance found in . . . rats as a model of fear-associated temperamental differences in humans.'

To separate the scared (neophobic) from the bold (neophilic) rats, they were put in a tank. New objects, such as a bowl, food hopper, tunnel and a brick, were introduced at five-minute intervals, while the rats' behaviour was monitored.

Neophobic rats inspected the objects only a little, whereas their bolder brothers were inquisitive and keen to explore. The scientists found that the average lifespan for the scared rats was 599 days, compared with 701 days for the bold rats.

Although the fearful rats died sooner, the causes of death were the same in both groups. About 80 per cent died from tumours associated with old age, especially in the pituitary gland.

'Most strikingly, males identified as neophobic during infancy died significantly earlier than males identified as neophilic during infancy,' the researchers wrote.

'However, pathology at the end of life was similar between the two kinds of males.'

This indicated that neophobia made the animals more vulnerable to diseases they were likely to get anyway as they aged.