A major new investigation which aims to solve two of the biggest unanswered questions in psychology is being launched by researchers at the University of Cambridge in partnership with the BBC.
The project, which will form the next phase of the BBC's successful online experiment, the "Big Personality Test", will attempt to explain whether people with similar tastes have more successful relationships, or if opposites attract?
It will also examine how far personality problems should be blamed on the parents, by testing whether our traits are inherited, or shaped by other influences, like childhood experiences and the environment in which we live.
The Big Personality Test is an online survey which was created in 2009 and has already become the largest ever scientific study of personality in Britain.
Its new phase involves a referral system, which will enable users to pass the survey on to family and friends. The results could prove groundbreaking, enabling social scientists to cross-refer the results and accumulate an unprecedented set of data on two of psychology's biggest unknowns.
"At the moment, we don't have much information about how far people form relationships on the strength of similar personalities," Dr. Jason Rentfrow, one of two Cambridge researchers who will study the results of the survey, said.
"One of the reasons for this is that many studies of personality have focused on young, middle class and white people. We don't know if their results apply to people of all ages, class or ethnic backgrounds. We hope that this survey will give us information from a more diverse cross-section of the British population, so that we can answer these questions."
The research will be carried out by Dr. Rentfrow and Professor Michael Lamb, who helped to design the original personality test and are based at Cambridge's Department of Social and Developmental Psychology.
The Big Personality Test measures how far each participant expresses each of the "Big Five" personality traits, which psychologists use widely to describe different aspects of human personality.
These are: Extraversion (traits like sociability, talkativeness and optimism); Agreeableness (friendliness, kindness, generosity); Conscientiousness (reliability, organisation, efficiency); Neuroticism (anxiety, stress, irritability) and Openness (creativity, curiosity and imagination).
Everyone exhibits these traits to a greater or lesser degree, which means that psychologists can use the results to build up a personality "fingerprint" of each participant and draw conclusions about how far personality shapes our lives.
Preliminary results from the first phase suggest, for example, that women tend to be caring, dependable, emotional and traditional while men are typically more competitive, distracted, reserved and analytical.
What psychologists don't yet know is how far similarities in their personalities are more likely to make men and women compatible. Previous studies have certainly suggested that people have happier relationships when they value the same things, but it is not clear whether, for example, individuals with similar interests but from drastically different social backgrounds would still make good partners.
Similarly, while current research suggests that our personalities are partly inherited and partly developed in response to our surroundings, the picture is unclear.
"One of the problems is that it's very easy for people to see what they want to see," Professor Lamb said. "Parents will almost certainly detect aspects of themselves in their children's personalities, but it's also possible that their children have developed those traits in response to their parenting. Often it is difficult to tell whether inheritance, conditioning, or both, is the cause."
The results of the survey will almost certainly be invaluable to the likes of dating agencies and social networking sites looking to match like-minded people, but they could also have much more serious applications.
Understanding how far personality affects the success of relationships could, for instance, inform research into divorce rates and perhaps even help to prevent divorces further down the line. Similarly, by understanding the links between personality and experience, researchers will be in a better position to predict and prepare for the impact of a disturbing psychological trauma on an individual.
The survey will run until the end of November 2010 and the Cambridge team expect to publish their first results during spring or summer 2011. To take the test, or for more information, please visit: www.bbc.co.uk/labuk/experiments/personality/
Explore further: Teenage self-harm linked to problems in later life