Put dead fish in a scanner, push the button, and see what happens:
“By complete, random chance, we found some voxels that were significant that just happened to be in the fish’s brain,” Bennett said. “And if I were a ridiculous researcher, I’d say, ‘A dead salmon perceiving humans can tell their emotional state.’”
The result is completely nuts — but that’s actually exactly the point. Bennett, who is now a post-doc at the University of California, Santa Barbara, and his adviser, George Wolford, wrote up the work as a warning about the dangers of false positives in fMRI data.
Our old friend, the multiple comparison -- 130,000 of them in this case. Elsewhere this month I was reading about the impressive fault-tolerance and noise-reducing properties of neural circuits. Those properties imply that functionally important signals will be lower than any reasonable false-positive threshold in a scan of so many multiple comparisons.
So the problem is inevitable. Here's what concerns me:
Bennett’s paper has been turned down by several publications, but a poster on the work received an appreciative audience at the Human Brain Mapping conference earlier this summer. Neuroscience researchers have been forwarding it to each other for weeks.
Yes, use the editorial process to silence the internal critiques. Good plan, there, neuroscientists.
(via Slashdot)
