In her latest popular neuroscience book, Professor Cordelia Fine takes us through the science that led to gender stereotypes

That there are innate behavioural differences between males and females is an argument commonly used to explain away sexual inequality. Women don’t earn as much as men because they are biologically disposed to not ask for a pay rise, the argument goes, or they naturally prefer jobs that involve ‘feminine’ qualities, such as childcare, (that also happen to be less well paid). Sex differences are also often used as reason and justification for gender specific marketing to children.

Testosterone Rex takes apart the science behind claims like these with clarity and humour, and shows how hard wired behavioural sex differences make little sense for a species designed to be as adaptable as we are. Filled with interesting facts, studies and arguments, it’s an impressive work, sure to be useful when faced with gender essentialists who argue that asking for progressive change such as fair representation, or less sexist adverts, is a futile fight against nature.

Biology, behaviour and social interaction

Fine breaks down a wide range of scientific experiments and offers convincing evidence that putting perceived differences in behaviour between men and women down to testosterone is a big mistake. Examples from the animal kingdom show us that even marked sex differences in brains may have little consequence for behaviour. And we see how data that seems to show gender differences can be deceiving and open to other interpretations.

Fine shows that behaviours and skills such as risk-taking, promiscuity and empathy, often mainly associated with one gender are shown to occur comparably across gender lines. And despite much conjecture around sex differences that have been found in the central nervous system, very few have been clearly linked to behaviour. Where sex based differences have been found, they are so small and there is so much overlap, that they don’t support the idea of men being one way and women another, but are better understood as individual differences.

When scientists examine behaviour it’s difficult, if not impossible, to disentangle biology from social processes, (this is besides taking into account the fact that cultural beliefs affect scientific process in the first place). It’s obvious that social interactions have an effect on behaviour, but our social lives also affect our biology.

Fine details a series of experiments on a type of cichlid fish that led to increased or decreased testosterone production, together with the loss of colourful markings and the shrinking or enlarging of testes. The experiments forced scientists to conclude that, in this type of fish, “social events regulate gonadal events.”

The size and colouring of the Cichlid fish signify its social status, but it’s more complicated for humans. As Fine notes, “stereotypes that stain every encounter, clothing, language, salaries, titles, awards, media, legislation, norms, jokes, art, religion… the list of phenomena that make up our rich, gendered cultures goes on and on.”

Gendered Childhood

The influence of early socialisation on our ideas about gender, including sex-segmented toy marketing, is just one part of our complex developmental system. Fine points out the irony that, “unconscious gender bias is now considered such an obstacle to the fair promotion and retention of women that organisations routinely invest considerable time and money in training to reduce it – yet we vigorously sow the seeds of it in our children from the moment they are born.”

The belief that biology determines interests and personalities is implicit in phrases like “boys will be boys” and it’s frequently invoked to justify marketing products specifically to boys or girls. ‘Biology will out’ we are told, (although why that means we still need to socialise children into gender roles isn’t clear.) But the evidence tells us that just like animal behaviour depends on early interactions, human behaviour too, depends on early social constructions. So when we divide toys, books, media and other childhood products into two distinct types, we foster the development of ‘typical’ boy/girl behaviour.

Beyond nature/nurture

Fine does not say that sex effects on the brain shouldn’t be studied, or suggest that our brains are infinitely plastic blank slates. Rather she advocates an approach that takes the developmental system seriously. We can’t divorce biology from environment. Biological sex is complex and entangled with many interacting dynamic factors.

Testosterone Rex attempts to take us beyond the nature/nurture debate. It shows us that much of the talk around testosterone is unfounded and that the key to social change comes from changing our social environment. Even the word ‘innate’ does not automatically mean fixed or unchangeable, human nature is not rigid and unchanging, and neither is human biology. Rather than explaining away gender inequality as ‘decreed by nature’, Fine shows us that we have the potential to create the kind of society we want.

Our brains and bodies adapt according to our experiences, our expectations and our environment. Old beliefs die, values change, societies organise in different ways. If we want to change society the challenge doesn’t come from our biology, it comes from the beliefs and attitudes that seek to explain away the status quo and by doing so, preserve it.