This is an absolute stunner of a popular science book – without doubt one of the best of 2006. The author does a brilliant job of demolishing the academic psychology establishment, by questioning a fundamental assumption that was made without properly checking it – that nurture would influence personality. She does all this in a very personal, human fashion, with as much reference to the way traditional crime fiction works as to scientific research. This side of the book is handled superbly well.
The key point that Judith Rich Harris makes is that while it can be shown that a percentage of our behaviour and personality comes from heredity, once you eliminate that genetic portion (just under half), it is very difficult to explain the rest. Specifically, she lays into those who just assume that this as a result of the way that our parents/carers mould our personality, pointing out that this bears no resemblance to reality – the reality for instance of identical twins, or even conjoined twins, brought up in the same environment having very different personalities.
Early on Harris likens her job to a fictional detective. A particularly apt comparison she makes is with the 1950s novel The Daughter of Time by Josephine Tey. In this, the hero, detective Alan Grant, is laid up in hospital throughout the book, and as a challenge takes on the task of exploring a historical mystery – the character of Richard III, and who killed the princes in the Tower. He shows how the “facts” that “everyone knows” are in truth based largely on propaganda and don’t necessarily bear in resemblance to reality. Harris too is working indirectly, but equally powerfully. Similarly, Harris suggests, the “facts” we know about how parenting shapes personality are more wishful thinking on the part of those with a vested interest in selling parenting books than necessarily anything with a scientific basis.
After casting aside five “red herrings” – potential explanations for the development of individual personality that she shows to be spurious, Harris is ready to present her own thesis. Influenced strongly by Steven Pinker’s description of the different functional modules of the brain, Harris suggests that there are three modules that, sometimes in contradictory fashion, shape our personality. A relationship module that deals with our information base on other people, a socialization module that helps us to fit in with groups by providing the ability to average across a wide range of inputs, and a status module that enables us to establish our position in the pecking order and to work on bettering ourselves. This isn’t in any sense proved – Harris would be the first to emphasize this – but her argument generally reads very well.
Perhaps the only point that isn’t totally clear is that while she says one of the reasons for difference between identical twins is different inputs to the socialization module, it’s not clear how this explains why, for instance, conjoined twins can be so different, as presumably their socialization experiences can’t be hugely different. Harris says they have different social experiences as people see that they are individuals, so distinguish – but that seems to be a bit of an assumption itself, that they aren’t in the style of Lord of the Flies seen as a single “Samneric” rather than Sam and Eric as separate entities, and also that such a distinction being made is enough to produce radically different socialization. Don’t most of us assume identical twins are very similar?
The only minor snag with the writing, is that Harris can be repetitive. This is particularly noticeable in the first chapter where she presents the message over and over again, so get through that chapter as soon as possible. You will find this tendency to repeat recurs, but at a significantly lower level. It’s also true that some won’t like her very personal style. This is very much the story of Ms Harris’s efforts, not a matter of pure scientific reporting. For this reviewer, though, that makes it much more approachable and fascinating – it’s a real page turner, and highly recommended.