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Comment by georgewfraser | Hacker News Reader

These studies are THE WORST. Your brain "changes" from 20 to 30. Does this change make it better? Is it even meaningful? No evidence is presented. Instead, we go on a detour into fMRI pseudoscience, which should properly be regarded as an extension of phrenology.

I would argue that the unsaid assumption of this article, that 30 year olds have superior judgement to 20 year olds, is debatable. Most people over 30 are risk-averse in the extreme, and will for example remain in a lousy career for their lives rather than take the risk of switching to a new track or moving to a new city.

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Exactly, it's like saying that your heart isn't "mature" until you're in your 60s, because before that point the arteries around it are still hardening.

Edit: I dunno about your "people over 30 are risk averse" comment, though. My 30s started off with me quitting my well-paid job to burn all my savings starting a company.

Well, I'm 38 now and can say with confidence, that during most of my 20s I was a naive idiot that could not see the forest for the trees. So, in my case, yes, I do have superior judgement in my 30s.

At least that what's your 38 year old brain tries to convince you of.

My experience has been the same. I'm 33 and sometimes it seems that I was not even fully conscious in my 20s as I am now. Hopefully this trend will continue and someday I'll look back and think I was a naive idiot at 33. :P

That's the philosophy I try to live by. I always assume that in 5-10 years I'll assume that current me will seem like an idiot.

Being more risk averse in your 30s? I'll beleive it. But why? Maybe not biological, hormonial, or genetic, but probably because in your 30s your parents are nearing retirement and need your help. You are starting a family and need stability. You are dating/marrying and need to be more dependable.

Why is this being downvoted? The parent poster complained about the article not presenting any evidence and then goes on to state that most people over 30 are extremely risk averse - without presenting any evidence.

Aren't we allowed to make any assumptions as to why that might be or if it is even true at all?

I've got enemies on HN. They follow me around and downvote my comments. No joke. Do not piss off "the tolerant ones".

I can see why the title of the article might trigger anxiety, but why do the studies upset you?

Is the data invalid? Is it wrong to gather data that may not be useful?

There are well-known problems with fMRI studies and particulary with how they are interpreted, see e.g. http://www.edvul.com/pdf/VulHarrisWinkielmanPashler-PPS-2009... (PDF) for a good critique. It's an intrinsically low-resolution tool as well, "there seems to be a lot of blood flow in vaguely this area of the brain", that is sold as if it were high tech and the only/best way to learn about human cognition.

I think it's important to point out that papers like that usually are pointing out statistical pitfalls (and often provide solutions), but they don't really cast doubt on fMRI as a tool for measuring brain function.

That's true and I don't think anybody disputes that fMRI is a good way to measure brain function, but (1) the improved statistical methods you talk about are often not adopted and (2) brain function is at a different level of abstraction than cognition and emotion, and making inferences about the latter based on the former is really hard, and would still be hard even with better statistics.

Agreed, I think those factors detract attention from some of the better designed experiments out there.

I became a total cynic toward the entire field of fMRI studies the day I found out that they found a dead salmon [0] could tell what emotions humans were depicting in photos.

[0] http://prefrontal.org/files/posters/Bennett-Salmon-2009.pdf

This is a prime example of what I described. The problem is not with fMRI as a tool, but with what statistical modeling assumptions are made when making inferences. In this case, it's about statistical thresholds and how to avoid false positives--something that is a concern for any experiment, not just one that using an fMRI. To make this clear, here's the discussion:

"Can we conclude from this data that the salmon is engaging in the perspective-taking task? Certainly not. What we can determine is that random noise in the EPI timeseries may yield spurious results if multiple comparisons are not controlled for. Adaptive methods for controlling the FDR and FWER are excellent options and are widely available in all major fMRI analysis packages. We argue that relying on standard statistical thresholds (p < 0.001) and low minimum cluster sizes (k > 8) is an ineffective control for multiple comparisons. We further argue that the vast majority of fMRI studies should be utilizing multiple comparisons correction as standard practice in the computation of their statistics."

The authors don't cast doubt on the entire field of fMRI, just in what conclusions we can draw from certain statistic tests of high dimensional data in the presence of noise...

To this reader, the point of the article seemed to be that while we understand some aspects of brain development, there is a lot of work ahead. They link to a Neuron paper, which is closer to what I think you were expecting:

http://dx.doi.org/10.1016/j.neuron.2016.10.059

That risk aversion might be correlated to the higher number of children one has at a higher age.

Or the realization that your 20s are not your best years, and that you still have up to 2x as many years ahead of you than behind you (or 5x the number of adult years). Risky behavior becomes less attractive when you understand the costs.

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