2012-10-02

This is how science works


http://blogs.scientificamerican.com/scicurious-brain/2012/09/25/ignobel-prize-in-neuroscience-the-dead-salmon-study/

The basic premise is that a bunch of scientists put a dead salmon in an fMRI and demonstrated brain activity.

Yes, in a dead, frozen salmon.

So in the final results, the authors compared the normal multiple comparisons, with the multiple CORRECTED comparisons. When they used the multiple corrected comparisons, the dead salmon showed nothing. When they did the multiple comparisons without the correction, the salmon showed significant increases in “activation”, coincidentally, in the brain and spinal cord. This shows the importance of correcting for multiple comparisons and avoiding false positives


The original poster almost didn’t make it to a conference, but when it did, it made a major splash, and reactions were very positive. Some people like to use the salmon study as proof that fMRI is woo, but this isn’t the case, it’s actually a study to show the importance of correcting your stats.

And the poster, and the paper that was eventually published, may have had an effect on the field. The authors note that at the time the poster was presented, between 25-40% of studies on fMRI being published were NOT using the corrected comparisons. But by the time this group won the Ignobel last week, that number had dropped to 10%. And who knows, it might, in part, be due to a dead fish.

Yes, that's right, a frozen fish - and the analysis of it - may have improved medical science.

The takeaway point, though is that you can do your data collection correctly but screw up your  analysis and still end up with a bad result.