[amirmc]

"During the behavior-evaluation exercise, people with high justice sensitivity showed more activity than average participants in parts of the brain associated with higher-order cognition. Brain areas commonly linked with emotional processing were not affected.

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.

[Ensorceled]

Can you explain why it does not follow instead of just putting not in italics for all the non-psychology PhD's in the crowd?

[amirmc]

I'll try breaking it down, along with the questions that came to mind as I read it.

... 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.

[kolbe]

Is this baseline you speak of a personal baseline for each participant in the study? Or is it like a canonical brain state that all other brains are compared to?

And pardon my leap of logic here (I'm not a neuroscientist), but why would a personal baseline affect the results? A personal baseline, intuitively, would not add to the goal of the study and could negate results that they're looking for. That is, a logical person will probably be more logical in his baseline, too. So, logical_observation - logical_baseline = 0. But what they're looking for is simply whether logic is being used in response to the experiment. And I wouldn't think the goal of the study is to find out whether people are more logical than their baseline, just whether they're more logical than other people who make different assessments.

Whereas, if we understand, based on previous work, that X things happen in an MRI when thinking logically and Y things happen when acting emotionally, why can't we simply correlate observations to these known states?

[amirmc]

The sibling comment is correct, in that you're always measuring differences. The 'baseline' isn't a canonical one but specific to your experimental design (and research question).

For example, if I were interested in which regions respond to pain and pleasure I have several ways I could design a study. I could have a 'pain' condition (drink something bitter), and a 'pleasure' condition (drink something sweet) and then just do comparisons between them (pain - pleasure, and the inverse). However, I could also include a 'neutral' condition (drink plain water) and now I can compare the emotional conditions against the 'neutral' one and extract the regions that are generally involved in emotion.

Also, your comment highlights another problem when research work is badly disseminated. The concept of logic is not being examined whatsoever, yet you've taken 'cognitively driven' (already a false statement) to mean 'logical'.

[fluidcruft]

What you observe in fMRI are always changes, not absolute measurements. So you end up comparing differences between changes.

Suppose you measure the height of two mountains their bases, but you want to make inferences about which mountain has the greatest elevation. To do that you have to compare the relative heights of the bases where the measurements were made.

[Ensorceled]

Excellent. I was having trouble following the connection between showing high justice sensitivity being associated with higher order cognition automatically meaning they subjects were cognitively driven. All else being true, they could be cognitively driven when thinking about matters of fairness and justice and emotionally driven otherwise.

Thanks.

[judk]

fMRI psych studies were debunked by the dead fish paper years ago. (In short: investigators misreport the measurement apparatus's random noise as significant results.) Why does the neuro community still publish fMRI psych papers? Is it is a case homeopahy where the quacks are the ones doing the peer rebiews and the entire specialty is a most cause?

[kenferry]

What the salmon study did was make some points about statistics in a funny way, but the authors were not trying to discredit fMRI as a whole.

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.

[amirmc]

fMRI is a tool. Just like every other tool it can be wielded skilfully or incompetently and in the case of fMRI you must do your stats properly (c.f. the Multiple Comparisons problem [1]). There's nothing out there that 'debunks' fMRI as a tool.

[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

[3] http://news.bbc.co.uk/1/hi/8497148.stm

[swederik]

If Adrian Owen was your co-supervisor, you should know better than to say that fMRI allows you to communicate with patients in a vegetative state. VS means, by definition, that the patient is unresponsive. Communication via fMRI or brain computer interface is still only possible with patients that are conscious (e.g. locked in, or in a minimally conscious state).

[amirmc]

"VS means, by definition, that the patient is unresponsive."

And IIRC they were VS until such studies demonstrated that actually not all of them were (which was my point).

[nealabq]

I assume this is the dead fish paper: http://prefrontal.org/blog/2009/09/the-story-behind-the-atla...

[edit] The above is a link to a blog post. Is this the paper: http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf

[fluidcruft]

The dead fish was attention whoring bullshit. I'm willing to bet you actually have no clue.