How old is "old"? People's perceptions of age are being investigated by psychologists at the University of St Andrews, in a bid to improve people's experience of ageing. Researcher Joanne Persson found that younger adults believed a person was old at 54.5 years, while older adults put it at 74. But Ms Persson said her preliminary survey showed that young participants were more likely to have experienced age discrimination than old people. "In the UK in 2001 the annual census showed that there were more people over 60 than under 16," she said. "Never in the nation's history have so many people lived into the later stages of their lives and remained so healthy and productive."