Forget men are from Mars and women are from Venus. The impression that today's youth and the older generation could be from different planets has just been backed up by science with the publication of the largest analysis ever carried out on how personality is changing over time. Conducted on almost 17,000 school and college students over the past 40 years, the US analysis firmly establishes that youth personality has dramatically changed since the 1960s, with each subsequent generation becoming much more outgoing and assertive.
Psychologists divide personality into two main types: extrovert and introvert. Extroverts are outgoing and sociable, while introverts prefer to be alone, often finding constant company overwhelming. They don't like being the centre of attention. When psychologist Jean Twinge at Case Western Reserve University in Cleveland, Ohio, analysed every comparable study of personality conducted on students since the 1960s, she found that school and university students today are on average 50 per cent more extrovert.
She also predicted that, if current trends continue, by the year 2010, college-age students will be almost twice as extrovert as those in the Sixties. Or to put it another way: the average student in 2010 will be more outgoing than just over 80 per cent of the population of the same age in the 1960s.
Increased family mobility may have contributed to this growth in "outgoingness". Changes in work patterns and the erosion of industry have encouraged families to move, as have rapidly rising housing prices and the need to stay ahead on the property ladder. Never before have so many young people had to learn to enter social networks in their neighbourhoods from scratch - a process that fosters sociability. Young couples end up miles from where they were born; their children have to learn how to interact with more and different people as they grow up.
The expansion of day care for the young may also be having the same effect.
In the past, children were mainly exposed to their parents and their neighbour's children. Now, in day care, they socialise with larger numbers of children, which makes them more outgoing, particularly if they are to make their mark.
Philosophies of child-rearing have also changed; in general, parents have become more permissive, with children now being allowed to speak their minds. The doctrine of being "seen and not heard" has long gone, a change that has most likely encouraged assertiveness.
Extroverts, while being more sociable, are not only more impulsive but also more easily bored. This could explain the dramatic rise among students of problems linked to impetuous tendencies such as eating disorders and drug abuse.
Research suggests that one of the best ways to help these more extrovert students improve academic performance is to design a "discourse-rich learning environment". Psychologists Michael Nussbaum and Lisa Bendixen of the University of Nevada have just published findings which show that students who are encouraged to engage in argument as a way of understanding their subject, experience dramatic improvements in their conceptual understanding. Given the natural preference of extroverts for discussion rather than solitary bookwork, encouraging argument and discussion seems to be a highly effective way of engaging them in academic life.
There is another covert advantage to this approach. Psychological probing of personality structure reveals extroverts are more concerned than introverts about how they come over to others. So extroverts are much more likely to study if they know it's going to help them argue better, and so look good, in front of an audience.
Dr Raj Persaud is a consultant psychiatrist at the Maudsley hospital and senior lecturer at the Institute of Psychiatry in London. He is a fellow of University College London, and author of "From the Edge of the Couch" published by Bantam Press, pound;12.99. Email: firstname.lastname@example.org