The conclusion was clear, Decety said: “Individuals who are sensitive to justice and fairness do not seem to be emotionally driven. Rather, they are cognitively driven.”"
While this is a very interesting study, that conclusion does not follow from the previous paragraph. I'd even bet that specific claim is not made in the original paper but was convenient to state in a non-peer-reviewed news story.
fMRI studies are extremely easy to perform and, frankly, if you put someone in a brain scanner bits of the brain will light up. I know this because my PhD was on the topic of human emotion and decision-making and I used fMRI (as well as PET). I'm going to skim the paper now and see if my earlier statement holds up.
EDIT: As I suspected, their claim is not made (even slightly) in the peer-reviewed work. I still find the study interesting but I see flaws in the study design as there isn't an attempt at a baseline condition which (imho) is important for any claims about emotional processing.
... people with high justice sensitivity showed more activity than average participants in parts of the brain associated with higher-order cognition.
What is the activity being measured relative to? One of the issues with any brain imaging study is the baseline condition you make comparisons with. To state that you saw more activity is only meaningful if you believe the baseline was appropriate.
Brain areas commonly linked with emotional processing were not affected.
Again, this must be relative to the baseline chosen, which the story doesn't mention but relies on. For example, in this study they do a comparison of Good vs Bad and then do the reverse comparison of Bad vs Good. If the emotional parts of the brain are equally active for both those conditions, then they'll simply disappear in the contrast. You may or may not care about this depending on your research question, but it does affect the claims you can later make. To be clear, I'm fine with the paragraph so far.
Individuals who are sensitive to justice and fairness do not seem to be emotionally driven. Rather, they are cognitively driven.
This is where I take umbrage. Nothing in the previous para claimed (or demonstrated) that there was a fundamental distinction between cognition and emotion per se. Yet this quote tries to boil it down and makes claims about the emotional aspects that the study cannot support. That the emotional regions of the brain showed no difference may simply be an artefact of the study design. Having read the paper, they didn't have a proper baseline comparison so I treat any claims related to emotional processing with suspicion.
If you look at most studies that came out before it did, they were already using statistical approaches that were robust to this sort of problem.
These include Bonferroni correction, cluster correction for spatial distributions, and Monte Carlo simulations and permutation testing.
These techniques analyze what you would expect to happen if there were no signal but a lot of random noise. You can then look for signals that are still significantly stronger than predicted by the null hypothesis. This is what most fMRI studies do, and this is not done (intentionally) in the dead salmon study. If you use 'em, you find nothing in the salmon.
[1] http://en.wikipedia.org/wiki/Multiple_comparisons_problem
Edit: Indeed fMRI allows us to do things we had no hope of doing before, e.g. communication with those who are otherwise in permanent vegetative states [2,3] (that guy was my co-supervisor).
[2] http://www.sciencemag.org/content/313/5792/1402.abstract
[edit] The above is a link to a blog post. Is this the paper: http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf
http://en.wikipedia.org/wiki/Polygraph#Validity
As with many technologies, though, you can't be a Luddite and slow progress because the general population might misunderstand it.
Such judgement appears unfair, and so (to misapply the conclusions of the original paper) rational people should be uncomfortable with it.
Hm, that is unlucky I supposed fMRI is the modern lie detector, where the test administrator just makes up results that the authorities rely on.
That was my first impression also. Then I noticed that the article comes to us from the field of social psychology, so I decided it didn't really matter how many words were used in ambiguous ways -- it's not science, after all.
Hooray for language.
