Brain scanning studies are usually too small to find reliable results

By Clare Wilson.

Brain scanning studies that use magnetic resonance imagery (MRI) machines are said to show links between the brain's structure or patterns of activity and certain aspects of personality. There have been suspicions that some of the results aren't trustworthy. That has been confirmed.

According to a study by Scott Marek at Washington University in St Louis and his colleagues, almost all such research has had too few participants to find reliable results. The group found that the studies need to look at the brains of thousands of people.

The UK Biobank study, which had scanned nearly 36,000 participants, was analysed by Marek and his team. They looked at links between brain structure and functioning and two relatively well-studied traits: cognitive ability and psychopathy.