Aha! news stories about what brain imaging reveals about human behavior are probably based on studies whose findings would not be confirmed by further research:
Brain imaging has shed much light on medical conditions in recent decades. So it was hardly good news for neuroscientist Scott Marek at the University of Washington when the results of a study linking brain function with intelligence in 2000 children produced very counterintuitive results. He and his colleagues had divided the sample into two groups of 1000 and run the same analysis on each — and they did not match. At first, he told Nature, “I stared out of my apartment window in depression, taking in what it meant for the field.”
Then the team decided to study the problem, using the three key studies in this type of research, the Adolescent Brain Cognitive Development (ABCD) study, Human Connectome Project (HCP) and the UK Biobank, amounting to 50,000 scans. The results were sobering:
As a result, the conclusions of most published ‘brain-wide association studies’ — typically involving dozens to hundreds of participants — might be wrong. Such studies link variations in brain structure and activity to differences in cognitive ability, mental health and other behavioural traits. For instance, numerous studies have identified brain anatomy or activity patterns that, the studies say, can distinguish people who have been diagnosed with depression from those who have not. Studies also often seek biomarkers for behavioural traits.
“There’s a lot of investigators who have committed their careers to doing the kind of science that this paper says is basically junk,” says Russell Poldrack, a cognitive neuroscientist at Stanford University in California, who was one of the paper’s peer reviewers. “It really forces a rethink.”
Ewen Callaway, “Can brain scans reveal behaviour? Bombshell study says not yet” at Nature (March 17, 2022) The paper requires a fee or subscription.
The challenged field is not brain imaging as such but a specific subset of brain imaging — brain wide association studies (BWAS) — that attempts to account for human behavior differences as differences in the human brain. Such studies, often of psychiatric conditions, were the Next Step for neuroimaging: showing that human behavior is based on simple, identifiable brain states. But that’s not what happened:
News, “Imaging studies fail badly at linking brain and behavior” at Mind Matters News (March 25, 2022)
Takehome: Such studies, often of psychiatric conditions, were the Next Step for brain imaging: showing that human behavior is based on simple, identifiable brain states.
You may also wish to read: No, fMRI brain scans are NOT reading our minds. After reading her perceptive essay about the problems in fMRI imaging in neuroscience, I’m sad that a gifted student has doubts about a career in the field. Neuroscience badly needs skeptics to show how unreliable technology, biased handling of data, and materialism’s conceptual mess frustrate science. (Michael Egnor)