Blueprint: How DNA makes us who we are
By Robert Plomin
Allen Lane, paperback, £20, 2018
Review by Dr Greg Dollman, medical adviser, MDDUS
THE psychologist Robert Plomin argues in his new book Blueprint that “genetics is the most important factor shaping who we are”. A keen advocate of ‘nature’ being the design of our individuality, Plomin does not seek to discard the influence of ‘nurture’, but holds that this is “mostly random”. He argues that the findings of decades of DNA research will shape the way we predict mental illness, and also influence how we parent and teach.
Plomin summarises the substantial subject matter: “Inherited DNA differences are the major systematic cause of who we are. DNA differences account for half of the variance of psychological traits. The rest of the variance is environmental, but that portion of the variance is mostly random, which means we can’t predict it or do much about it.”
He clearly wants to start a discussion…
Plomin considers heritability (“the one per cent of DNA that differs between us and contributes to our differences in behaviour”) to understand the reason why we are different psychologically, even when environments are shared. He states that while our circumstances will direct outcomes, the genetic differences in personality increase this happening. So our genetic makeup will determine our response to external events.
‘What about the impact of death, illness or divorce?’, I hear you exclaim. Plomin argues that, genetics aside, any significant environmental factors boil down to chance. They involve random experiences over which we hold little control. As such, Plomin concludes that long term effects are insignificant. He writes: “life experiences matter, but they don’t make a difference”. Even when looking at society’s influence, he believes these factors have little impact on an individual’s personality.
Plomin also explores the impact of this theory on individuals, society and psychology. He looks, for example, at predictor scores for mental illness, including schizophrenia and Alzheimer’s, considering how we may use the findings to improve future detection and management. He does acknowledge, however, the dilemma in identifying genetic risk when we are (currently) unable to do anything about it.
Plomin acknowledges that the theory is complex, and that it will challenge our ideas of who we are and what makes us different. He writes elegantly, and explains carefully his specialty. The book is accessible and thought-provoking.