Psychology researchers and Lothian Birth Cohorts featured in BBC Two programme

PPLS researchers in Psychology Professor Ian Deary and Dr Simon Cox appear in Horizon's 'The Great British Intelligence Test' on BBC Two

Psychology researchers Dr Simon Cox and Professor Ian Deary spoke with Michael Mosley, Dr Hannah Fry and mathematician Bobby Seagull about brain matter and structure, neuropathways, and whether these can explain differences in intelligence. 

Using the Lothian Birth Cohort DTI imaging protocal at Edinburgh, researchers scanned Bobby's brain as a way to measure intelligence and answer the questions: Are clever brains bigger? Are they wired differently? What determines intelligence?

Brain size isn't everything

Results from the scan showed that while Bobby's brain volume is below average, he had a healthy amount of grey matter, the part of the brain where computation and calculations happen. Simon expanded on the results saying, "It seems that individuals with more grey matter have slightly higher cognitive ability."

Significance of white matter

It is not just grey matter that plays a role in understanding intelligence. White matter, and the neuropathways within it, is crucial to the speed of thinking.

Insulating the neuropathways is a fatty substance called myelin, which contributes to the speed and efficiency of communication between signals.

As the programme explains, "Simon's research suggests that these well-insulated pathways are something that clever brains like Bobby's have in common." In other words, the more white matter the brain has, the more myelin there is to insulate the neuropathways, the faster the brain can think.

Intelligence and aging

Professor of Differential Psychology Ian Deary's IQ research on the Lothian Birth Cohorts was also featured on 'The Great British Intelligence Test,' shining a light on why some people's brains and thinking skills age better than others.

Overall, lifestyle factors play a significant role in how well people think later in life. As the programme explains, "Ian's research has shown that those who were consistently physically and mentally active had better thinking skills in older age, as did those who learned a second language."

Ian explains the basics about IQ in his latest book, Intelligence: A Very Short Introduction.

Watch 'The Great British Intelligence Test'

The full episode of Horizon's 'The Great British Intelligence Test' that aired on 4 May 2020 is available on BBC iPlayer.

The Great British Intelligence Test

Related links

Healthy mental ageing: the Lothian Birth Cohorts

Psychology at the University of Edinburgh