[HN Gopher] Can brain scans reveal behaviour? Study says not yet
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       Can brain scans reveal behaviour? Study says not yet
        
       Author : Anon84
       Score  : 29 points
       Date   : 2022-04-25 14:41 UTC (8 hours ago)
        
 (HTM) web link (www.nature.com)
 (TXT) w3m dump (www.nature.com)
        
       | Enginerrrd wrote:
       | I had a conversation with a PhD neuroscientist who was quite
       | prominent and good in her field. She didn't have nice things to
       | say about fMRI studies. Full Stop. That was ~10 years ago, so I'm
       | sure techniques have improved, but she was arguing on the
       | principle that the time scales on which it can measure just
       | aren't conducive to measuring the actual activity that neurons
       | produce.
        
       | raxxorraxor wrote:
       | It is a pretty long standing joke in medicine that neurologists
       | know nothing about how the brain functions so the "bombshell"
       | description is quite funny.
        
       | elsherbini wrote:
       | One generalizable takeaway from this - smaller studies can only
       | show really huge effect sizes. This is what statistical power
       | means - to see small differences between groups you need really
       | large samples. This is fine if you have actually have a huge
       | effect - you probably don't need a large sample size to detect if
       | sugar causes insulin levels to go up in people that are fasting.
       | 
       | But if you don't really have large effect sizes in whatever you
       | are studying, then you are screwed. All your statistically
       | significant results are going to have really large effect sizes,
       | because those are the only ones you can see in your small sample
       | size. If you didn't get a significant result, you don't publish,
       | or you stop following up, and if you do get a significant result
       | you publish and do more follow up studies. In time with larger
       | studies or new technology that changes how we can measure things,
       | it becomes apparent that you were chasing noise.
        
       | probIs8 wrote:
        
       | endofreach wrote:
       | I can't remember where I've read it, but James Fellon was
       | studying patterns in brain scans that indicate a psychopath. He
       | found out, he himself is a psychopath.
       | 
       | I just remember the anecdote, not the outcome of his studies.
        
         | monkeybutton wrote:
         | His autobiography "The Psychopath Inside" is quite
         | entertaining.
        
       | SubiculumCode wrote:
       | A lot of these studies use measures for, let's say, memory that
       | are very general that mix multiple memory processes,depending on
       | more distributed brain networks. Some types of memory tests are
       | known to be especially hippocampal dependent, and thus larger
       | effect sizes can be observed (e.g. requiring association between
       | objects, and without the use of mnemonic strategies.)
        
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       (page generated 2022-04-25 23:02 UTC)