In 2019, neuroscientist Scott Marek was asked to contribute a paper to a journal that focuses on child development. Previous studies had shown that differences in brain function between children were linked with performance in intelligence tests. So Marek decided to examine this trend in 2,000 kids.
Brain-imaging data sets had been swelling in size. To show that this growth was making studies more reliable, Marek, based at Washington University in St. Louis, Missouri (WashU), and his colleagues split the data in two and ran the same analysis on each subset, expecting the results to match.
Instead, they found the opposite. โI was shocked. I thought it was going to look exactly the same in both sets,โ says Marek. โI stared out of my apartment window in depression, taking in what it meant for the field.โ
Now, in a bombshell 16 March Nature study, Marek and his colleagues show that even large brain-imaging studies, such as his, are still too small to reliably detect most links between brain function and behaviour.
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As a result, the conclusions of most published โbrain-wide association studiesโ โ typically involving dozens to hundreds of participants โ might be wrong.
