Nature versus Nurture: the state of play

The Blank Slate, more readily recognised in its original Latin as tabula rasa, is the soubriquet for the view that in the eternal Nature-Nurture debate the scales tip heavily in favour of the environment: when it comes to the human mind, nothing is left to the caprice of genes. Steven Pinker, well known for The Language Instinct and to a lesser extent How the Mind Works, devotes some 500 pages to refuting this stance. Effectively, then, this book is all about human nature – its validation, characterisation, and neurological basis, along with all its wider moral, political and social baggage.

Given the ambitious theme, and indeed the admirably detailed though sometimes long-winded narrative, it is surprising to find no mention of Sigmund Freud, who might justifiably have claimed to have started this particular ball rolling. After all, Freud renounced the primitive neurology of his day, to use psychoanalysis as a tool for understanding human nature: he earned his place in history by analysing behaviour in the now familiar terms of the atavistic Id, the enabling Ego, and the moralistic Super-ego. Surely consideration of these classical concepts would have been relevant to Pinker’s thesis?

Nonetheless, the uninitiated and specialist alike will enjoy the subsequent defence of that thesis against various potential counter-arguments. Pinker cautions quite correctly that behaviours are not entirely ‘genetic’ or ‘environmental’ in their cause, but rather that there is a probability of varying degrees, that some trait will surface in our psychological repertoire. Yet Pinker emphasises ‘Nature’, and a recent finding, not mentioned in his book, should stand as a salutary reminder of the persistent influence of ‘Nurture’. In mice with the gene ‘for’ the movement disorder Huntington’s Chorea, where the probability of occurrence in identical twins is 100 per cent, the degree of impairment and age of onset can still be reduced and delayed respectively by placing the mice in a stimulating environment.