- As another commenter said, this is a known disadvantage of averages. I'm curious if it's possible to get a median result from per-individual averages. I'm not familiar enough with how this research is done to get a result.
- Was any effort made to re-test individuals in a second/third/etc session, showing consistent patterns to the brain activity? I know it was consistent within a session, but I'm curious if it might change week over week.
> when analyzing average trends in groups of children, slower reaction times to the “Go” signal were linked to increased activity in many brain regions, including the default mode network
> However, when an individual had a slower reaction time to the “Go” signal, activity decreased in the default mode network — the opposite of the group-level pattern.
Imagine there are two groups A and B. One group, A, has slower reactions on average and high average activity The other, Group B, has higher reactions and lower than the Group A's activity. Yet inside both groups the general trend is that if someone is slower than the average reaction of their group then they're also below the average activity for their group.
If we look at the overall means without distinguishing groups, slower reaction is correlated positively with higher activity (kids from group A have higher activity and slower reaction in general, which pushes the correlation upwards. As long as the relationship in Group B isn't too strong the upward trend from Group A can easily dominate overall correlation) but inside each group the trend is actually the opposite.
This applies pretty much every time you're comparing samples. If I understood your quote correctly, they're studying a child's reaction time vs activity level by comparing the same kid in different times. The same logic applies, a person can exhibit the opposite trend to the populational average due to the same mechanism above. This can be even more dramatic, because once you start looking at averages you start losing time dependency information.
More broadly (and more formally), multivariate covariance splits in within-group and between-group terms, so if the signs of the terms are different the magnitude of one can dominate the overall sum and flip the sign.
It can go arbitrarily deep and the trend can flip sign for each added controlled variable.
At a group level, some kids are slower at this Stop/Go task than others. The group difference appears to be this increased broad-scale brain activity: the slow group is overall more prone to distraction and daydreaming.
However, at an individual level, slowing down on the task means increasing your focus (and decreasing brain activity in irrelevant regions), regardless of whether you were in the slow group or the fast group. So the group-level difference is not necessarily as profound as it might appear, and applying "slow group" with too broad a brush means you're going to sweep up some kids who are naturally cautious and focused.
Denying that first impulse, thinking about it, and then acting is slow.
It's a classic psychological phenomenon, where individual differences are obscuring time course patterns and vice versa.
Of course, this sidesteps the question of why (in the hypothetical example) the overall individual differences exist. Assuming those general individual differences are reliable and "real", you still have to explain why they are there, and if they predict significant outcomes, why they do, and so forth.
The message of the paper is good, although I think the press release (not surprisingly) overstates the significance of the paper. I think these kinds of issues have received a lot more attention in the literature in the last decade or so in neuroscience. It also sort of sidesteps a lot of the more thorny questions about truly person-specific patterns and how to determine when they're meaningful.
Now that we’re finally moving to the next stage of neuroscience due inscrutable latent systems (aka LLMs), I can’t help but feel some nostalgia. It’s all fun and games until someone makes a lie detection helmet that actually works…
Just from reading the link, I do see an objection: they studied repetitions, which are known to be different from the initial response, so this may not be the fMRI's eulogy.
https://www.nature.com/articles/s41467-026-71404-0
Mistry, P.K., Branigan, N.K., Gao, Z. et al. Nonergodicity and Simpson’s paradox in neurocognitive dynamics of cognitive control. Nat Commun 17, 3494 (2026). https://doi.org/10.1038/s41467-026-71404-0
This should surprise no one. You took a large population and found subpopulations within it. If you want to look at a population average, then use the population data. If you want to look at kids with specific attention needs (guessing ADHD since medical related) then design a study to select for children fitting that criteria, including subtypes.
This seems like the type of thing that should have had a study about study design done long ago that they could have followed to help them structure their own population selection.
The Maximegalon Institute of Slowly and Painfully Working Out the Surprisingly Obvious (MISPWOSO) is a fictional research institution from Douglas Adams' The Hitchhiker's Guide to the Galaxy series.
HN commenters have a far greater history of that.
Also, researchers trained for years and invested a long time on this work; the HN commenter probably invested a minuted or two.
It may very well be true, it is also true that HN commenters can be quite good at spotting math errors. The broader point being that people make mistakes sometimes or even that people sometimes don't have the same knowledge and information as others.
> researchers trained for years and invested a long time on this work; the HN commenter probably invested a minuted or two
Or it can also be postulated that the researchers were highly focused on the aspect of the work they were trained and interested in and may have lacked focus on the auxiliary fields. And that the HN commenter, while only spending a few minutes on this, was knowledgeable about the auxiliary field and immediately spotted a potential issue.
This is actually great and why its good to get papers published and read by a wide audience, because nobody can be good at everything.
They can be quite good at making that claim, which is cheap. And others like to rally around it - just like the comments rejecting most OPs that make their way to the top.
I'd need to see evidence that the claims are actually valid. Most similar HN take-downs, for fields I have knowledge of, are pretty poor.
B) “some people have been wrong before” is not a reason to think you know better than the authors of an upcoming Nature article based on a few layperson-targeted paragraphs summarizing the paper from a very high level.
Nor is "this paper is going to appear in Nature" a reason not to wonder whether there might be something that the authors don't know. The whole point of science is that anyone can make an informed critique and self-evaluation of it, with no necessity of depending on a priesthood to interpret it. You can point out the flaws in giantg2's argument https://news.ycombinator.com/item?id=47995899, but neither the venue of the paper, nor the fact that the argument is directed at laypeople in a forum frequented by laypeople, seems to me inherently to indicate such flaws.
That's a misinterpretation:
> anyone can
(Of course nothing stops them, but I don't think that's your point.)
> anyone can make an informed critique and self-evaluation of it, with no necessity of depending on a priesthood to interpret it.
Science is specifically not the wisdom of the crowds - that is pre-scientific. It is the wisdom of emprical facts, which are usually so complex and voluminous that it takes great expertise to understand and interpret them. Science is not democratic - your opinion is worthless and does not deserve consideration unless you can demonstrate otherwise.
You don't have to be in the priesthood, but it's tough to have the expertise otherwise, and then tough to stay outside the priesthood.
"'In matters of science,' Galileo wrote, 'the authority of thousands is not worth the humble reasoning of one single person.'" ("In questioni di scienza L'autorità di mille non vale l'umile ragionare di un singolo." The source was not able to verfy its provenance, however.)
HN is democratic, however.
For the record I have published in Nature Communications (and not Nature) and therefore know a little bit about what it takes to publish papers there.
> > anyone can make an informed critique and self-evaluation of it, with no necessity of depending on a priesthood to interpret it.
> Science is specifically not the wisdom of the crowds - that is pre-scientific. It is the wisdom of emprical facts, which are usually so complex and voluminous that it takes great expertise to understand and interpret them. Science is not democratic - your opinion is worthless and does not deserve consideration unless you can demonstrate otherwise.
I did not say that science is democratic, nor that the validity of a scientific fact is determined by the crowds, but rather that anyone can make an informed critique and self-evaluation. 'Can' is perhaps too strong a word; to do this is a skill that usually requires considerable background and training.
Here I think that one must distinguish between the sociology of science and the ideal of science. In the sociology of science, reputation matters, authority is often deferred to, and an amateur will have a tough time getting a serious hearing. That is the fact of imperfect human practice.
But the ideal of science is that everyone's idea does matter, or, if you like (though I find it pessimistic), that everyone's ideas don't matter. The ideas of the most untrained novice have exactly as much, or as little, scientific weight as those of the most expert, practiced, and credentialed scientist. This is distinct from the sociological weight of an idea: the scientific community is more likely to listen to the expert, practiced, and credentialed scientist than to the novice. But the quality of a scientific idea is intrinsic to the idea, not to who has it.
> imperfect human practice
Whether human social habits affect it or not (I agree they probably do), it would be impossible to spend time examining every amateur idea. And if you see the quality of many amateur ideas - even in a relatively sophisticated population like HN - the payoff gets worse.
This would indeed be best, no argument here. But this comment thread was more about whether, without evidence, that automatically dismissing a comment because it was on HN or automatically accepting a claim because it was from 'stanford researchers' was ok.