Why is there the assumption that the scan lighting up more brightly correlates with a particular psychological fact about the participants? The brain’s more complex than that. I’ve seen tests of cognitive tasks where the people that performed better had lower brain activity (it’s speculated that the successful brains were efficiently activating only the pathways that were needed, whereas the lower-performing participants’ brains were more often trying “everything” to look for what would work, but not really tuned in to a specific approach).

I’m not saying it doesn’t correlate for this study, just that it’s a little surprising that the study seems to take it as a given that strength of scanned activity == strength of psychological response.