What Makes Us Who We Are?
Do we inherit our personality, like the colour of our eyes? Or are our life experiences more important? How far could, and should, science predict our behaviour from looking at our genes?
It goes without saying that people resemble their relatives - one look through the family album tells us that!
But are these resemblances more than skin deep?
To try and answer these questions, scientists study twins. Because identical twins have identical genes, differences in their personality must be influenced by other factors.
Researchers compare identical twins brought up together, with identical twins who have been separated at birth. They can get an idea of how much of an individual's personality is shaped by genes, and how much is shaped by environment and experience.
With the emergence of new genetic techniques, researchers can look at genes a little more closely. Scientists have been searching for single genes that might influence certain kinds of behaviour.
So far, none have been found. The genes involved in human behaviour are much more complicated - there are lots of genes involved in each kind of behaviour, all interacting with each other and with the environment.
Some people fear a world in which genes are manipulated to produce 'designer babies'. If a person's behaviour was determined solely by the action of single genes, which were identified, then perhaps this would be possible.
But it's not!
The development of an individual's personality is a complex process involving the interaction of multiple genes along with the contribution of many other factors...the environment in which the person grows up, the experiences they have, the stresses and strains of life, chance events.
These all combine during the course of our development to determine our personality...to make us who we are.
Emeritus Professor of Psychology at the Institute of Psychiatry in London, Jeffrey Gray's interest in personality goes back a long way.
He's best known for developing a new theory of personality development, based on reward and punishment. His current work focuses on the effects on personality of differences in the genes and the brain. He's particularly interested in the neuropsychology of anxiety and schizophrenia. His work also involves applying an understanding of personality to the real world, such as in the workplace.
Jeffrey is also keen to discuss concepts of responsibility - what level of responsibility does an individual have for his personality, and how much responsibility should society have as a whole?
Peter McGuffin is director of the Social, Genetic and Developmental Psychiatry Centre at the Institute of Psychiatry in London.
He's particularly interested in the genetics of normal and abnormal behaviour. He has conducted numerous twin studies, looking at the relationship between inheritance of genes and certain aspects of personality...such as criminality.
He is also interested in gene mapping, and trying to understand the interaction between genes and the environment in forming personality.
John Carey is Merton Professor of English at Oxford University. Although most famous for his association with literature, he has a keen interest in science and society.
He was editor of the Faber Book of Science, and more recently the Faber Book of Utopia, experiences which put him in good stead to contribute to this programme.
He's particularly interested in debating the implications of an increasing knowledge of the genetics of personality...including ideas of moral responsibility.
Mike Maier is a consultant psychiatrist at Charing Cross Hospital and Senior Lecturer at Imperial College London.
His research focuses on schizophrenia. He is also interested in personality disorder...how are personality disorders defined, and how should society act to cope with individuals who have personality disorders?
Leading the debate...Colin Blakemore
Colin Blakemore is Waynflete Professor of Physiology at Oxford University and director of the Oxford Centre for Neuroscience.
A TV and radio regular, he's host of 'The Next Big Thing'.
His research interests - the brain and cognition - make him particularly well-placed to chair this programme.
Find out more
Robert Plomin, John C Defries, Gerald E McClearn, Michael Rutter
W H Freeman & Co
Nature & Nurture: An Introduction to Human Behavioural Genetics
Wadsworth Publishing Co
Twins: And What They Tell Us About Who We Are
John Wiley & Sons
Living With Our Genes: Why They Matter More Than You Think
Dean H. Hamer, Peter Copeland
Happy families: a twin study of humour
Twin Research (2000) 3(1): 17 - 22
'Opportunities for psychiatry from genetic findings'
Michael Rutter and Robert Ploming
British Journal of Psychiatry (1997) 171: 209 - 219
The Genetic Basis of Complex Human Behaviours
Robert Plomin, Michael J Owen, Peter McGuffin
Science Vol. 264 17 June 1994