The Longevity Project questions some widely held assumptions about the secrets of longevity. It is the result of twenty years research by Howard S. Friedman, Distinguished Professor of Psychology at the University of California, Riverside, assisted by his co author, Leslie R Martin, Professor of Psychology at La Sierra University.
They reviewed data collected from a previous long term research study, from 1921 onwards, which focused on 1500 bright boys and girls in California, to identify which factors influenced how long the different participants lived.
Although based on a substantial scientific study the book is very readable, aimed at a lay audience and enlivened by self tests and case studies of partipants (some of whom went on to achieve varying degrees of fame or fortune).
A surprising key finding was that the best predictor of longevity appeared to be conscientiousness - ‘The young adults who were thrifty, persistent, detail oriented and responsible lived the longest.’
The authors give three explanations for this. First, conscientious people tend to lead less risky lives –‘They are less likely to smoke, drink to excess, abuse drugs or drive too fast. They are more likely to wear seat belts and to follow doctors’ orders.’ Second, conscientious people seem biologically predisposed to live longer (possibly due to different serotinin levels in the brain). Third, conscientious people, ‘find their way to happier marriages, better friendships and healthier work situations’ with all the attendant health benefits.
They also found significant gender differences – with religion, for instance, helping women live longer (but not men) while men’s longevity appeared to be more adversely affected by divorce or the death of their spouse than women’s - and with masculine men least likely to live to an old age and feminine women the most likely.
Friedman and Martin turn on its head some current thinking about longevity. For instance they argue that sociability, happiness, optimism, marriage and level of education, in themselves, add no more years to life. They note that sociability can lead to peer pressure to pursue risky behaviour when young; that social relationships are more important to physical health and long life than happiness per se (although being involved in social and altruistic activities tends to make people happy); that a sexually satisfying and happy marriage is a very good indicator of future health and long life but that being unhappily married is not; and that level of education is often simply an indicator of how conscientious someone has been, with the better educated tending to be more successful in their lives, ‘because they were the kind of persistent people who were better able and motivated to navigate life’s personal and social challenges.’
However, their findings did suggest that being active in middle age was important for health and longevity, in line with conventional wisdom.
Conversely they argue that long hours at work and the challenges of daily life (as opposed to unusual and protracted stress, for instance from active combat in war) do little damage to our health. They claim moderate worrying is health protective and that neurotic men who are widowed live longer than their non neurotic counterparts (possibly because they follow up possible signs of ill health rather than ignoring them). They also noted, among the older participants in the study, ‘The continually productive men and women lived much longer than their more laid back comrades,’ suggesting a relaxing retirement may not be most conducive to longevity.
When considering the best predictor of long life Friedman and Martin conclude, ‘It was those who – through an often complex pattern of persistence, prudence, hard work, and close involvement with friends and communities – headed down meaningful interesting life paths and, as we have illustrated, found their way back to these healthy paths each time they were pushed off the road.’
Their conclusions have certainly sparked interest – generating over 300 references on Google within a few months of publication. How valid are they?
The authors recognise some of the inherent limitations in their research. As they say, ‘Any finding that comes out of a long term study, even a careful one, is ‘outdated’ by the time the results come in.’ However, they argue this simply means we need to examine the assumptions and conditions and see if they hold true in other places and times. With this in mind the authors refer, throughout the book, to other research which potentially corroborates their findings.
They also recognize that the group researched was selective (bright, predominantly white children in California); and that the role of women has changed significantly during the lifetime of the participants.
These caveats aside, the findings appear both evidence based and plausible and suggest an interesting perspective on human longevity. They also raise questions about modern society. Friedman and Martin say their studies, ‘Suggest that a society with more conscientious and goal oriented citizens, well integrated into their communities, is likely to be a society of health and long life.’ Reading these words in August 2011, with rioting, arson and looting in cities across the UK, suggests how far we may still have to go to achieve this.
The Longevity Project Howard S Friedman PhD and Leslie R Martin PhD Hay House ISBN 978 - 1 -8485 - 0431-8