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0 pointsamirmc12y ago0 comments

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.

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4 comments · 2 top-level

kolbe12y ago· 2 in thread

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?

amirmcOP12y ago

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'.

fluidcruft12y ago

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.

Ensorceled12y ago

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.

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