This post was contributed by Lucy Tallentire, from the School of Business, Economics and Informatics

Sex differences have been the source of contentious debate in recent years, beguiling scientists, lay people and major stakeholders like the NHS and pharmaceutical companies. There are obvious physiological and anatomical differences between the sexes but cognitive differences are often conveyed through stereotypes – that males have better motor and spatial abilities and females have superior memory and social cognition skills, for example. While there is research to support some areas of cognitive sex difference, recent studies have shown that the magnitude of sex differences has decreased in recent years. This suggests the causes of these differences may have less to do with one’s genetics than one’s environment – that nurture may be just as powerful as nature to one’s brain development. It also provides further evidence for the effectiveness of contemporary social movements to bridge the gap between “women’s roles” as nurturing child-bearers and “men’s roles” as workers.

So what can research into typical and atypical early development tell us about sex differences? And should we be focusing on biology as the route of sex differences?  These were just some of the questions addressed by guest speaker Teodora Gliga, from Birkbeck’s Centre for Brain and Cognitive Development, at a special seminar on Wednesday 7 December. The event was arranged and hosted by the Birkbeck TRIGGER initiative, a European-wide research project dedicated to Transforming Institutions by Gendering Contents and Gaining Equality in Research.

Why look at sex differences?

Hormonal differences initiated by biology and genes affect physical and cognitive development; the genes on sex chromosomes and the levels of sex hormones influence the brain during early development. Many psychiatric disorders are more common either in boys or girls; boys are more likely to develop autism – the focus of Teea’s research – but girls are more prone to anxiety. By utilising animal models of development and human studies that have revealed early biological differences between sexes present even before birth, Teodora was able to explain differences in susceptibility to risk factors associated with autism.

However, that the effect is amplified when the brain is exposed to risk factors or adversity, such as stress, demonstrates that biology is not the only variable in the development of a disorder like autism; recent research by Anne Fausto-Sterling on how best to study difference in infant early development has shown that, although birth characteristics provide a moment to begin analysis of developmental processes that lead to sex-related differences in behaviour and preference, this is an arbitrary starting point. Many of the biologically-oriented studies use prenatal sex differences in hormone production as the explanation for later difference in behaviour but according to Fausto-Sterling, it seems likely that hormones are but one of many factors affecting human foetal growth and development. In this framework, behaviour after birth develops independently as small biological differences are slowly magnified by external influences – social, cultural and environmental.

Case Study: The British Autism Study of Infant Siblings

The British Autism Study of Infant Siblings was established to explore the development of autism in young infants, and to advance and improve early detection and diagnosis. Parents frequently tell medical professionals that they knew there was something different about their child’s development quite early on, often long before an official diagnosis is received. However, it has been hard for researchers and clinicians to know about the very early signs for autism as they typically only see the child when they are over three years old, when a diagnosis can be reliably given. Although diagnoses for autism spectrum disorder (ASD) have fallen in recent years, it remains more commonly developed by boys – 1:42 boys and 1:189 girls, according to studies from 2010 and 2014.

Scientific understanding of the neurobiological basis of autism has advanced dramatically in past decades, but there is still very little known about how the condition develops over the first few years. This is precisely why Teea’s team at the Birkbeck Babylab launched the Studying Autism and ADHD Risks (STAARS) project, which looks specifically at the early development of baby brothers and sisters of children with autism spectrum disorders, attention deficit disorders and typical development. The project is notably an output of the TRIGGER programme, as the initiative provided the funding for the research assistant who carried out the analysis.

Of the participants with elder siblings with an ASD diagnosis, 20% went on to develop and get a diagnosis for ASD. The study showed a negative correlation between IQ and severity of symptoms, which provides further evidence that IQ is a protective factor against the development of autism. But Teodora was quick to remind the audience that there is still a lot of debate on these findings – there has not been one specific gene that can explain more than 10% of cases. One must also consider that the symptoms of autism might be exposed more easily in this case study, as it must be conducted on “High Risk” families, where they might be more actively looking for symptoms because of a heightened awareness of autism, and where interactions with siblings with an ASD diagnosis might even be a contributory environmental factor.

Teea finished her presentation with a call for more statistics and better models through which to analyse these statistics. If we are to gain a deeper understanding of ASD, its causes and its early detection, we must focus first on mediating effects that may reveal protective mechanisms, and on increasing our understanding of underlying biology of sex differences and the implications of hormones. According to the expert, “it is a story of interactions between biological, social and cultural factors with cascading effects.”

Further Links:

• The TRIGGER project at Birkbeck
• Follow TriggerBBK on Twitter
• The Centre for Brain and Cognitive Development
• Birkbeck Babylab
• British Autism Study of Baby Siblings project
• STAARS project

The TRIGGER team at Birkbeck is currently seeking mentees and mentors for their Athena SWAN mentoring programme 2016/17. The mentoring scheme is open to research, technical and academic staff who work at Birkbeck – find out more here.