This is what I meant about quantifying the probability estimate before clarifying the exact question. As I said originally, I’m skeptical of a strong heritability for rationality independent of IQ. I’m not sure what the correct statistical terminology is for talking about this kind of question. I think there is a low probability that a targeted genetic modification could increase rationality independent of IQ in a significant and measurable way. That belief doesn’t map in a straightforward way onto a claim about the heritability of rationality. I’m expecting What Intelligence Tests Miss to help clarify my thinking about what kind of test could even be used to reliably separate a ‘rationality’ cognitive trait from IQ which would be a necessary precondition to measuring the heritability of rationality.
Given that memory, verbal intelligence, spatial reasoning and general intelligence all have values of H of around 0.4, it seems that P{H>0.3) ~ 70%
These all correlate significantly with IQ however I believe (correct me if you think I’m wrong on this). It’s at least plausible that targeted genetic modifications could improve say spatial or verbal reasoning significantly more than IQ (perhaps by lowering scores in other areas) since there is some evidence of sex differences in these traits. Rationality seems more like a way of reasoning and a higher level trait than these ‘specialized’ forms of intelligence however.
Rationality seems more like a way of reasoning and a higher level trait than these ‘specialized’ forms of intelligence however.
Maybe. Actually, I think that the dominant theory around here is that rationality is actually the result of an atrophied motivated-cognition module, so perfect rationality is not a question of creating a new brain module, but subtracting off the distorting mechanisms that we are blighted with.
I realize that “brain module” != “distinct patch of cortex real estate”, but have there been any cases of brain damage that have increased a person’s rationality in some areas? I am aware that depression and certain autism spectrum traits have this property, but I’m curious if physical trauma has done anything similar.
I don’t know, but without a standardized test for rationality (like there is for IQ), how would we even notice?
Googling for “can brain injury cause autism” leads to conflicting info:
“This is a question which arises again and again, it’s other form is ‘Can brain injury cause autism?’ Of course the answer is most definitely, yes!”
“Blows to the head, lack of oxygen, and other physical trauma can certainly cause brain damage. Brain damaged children may have behaviors similar to those of autistic children. But physical injury cannot cause accurately diagnosed autism. Certainly a few non-traumatic falls in infancy are NOT the cause of autism in a toddler.”
To test this, you’d need to somehow identify a group of patients that were going to receive some kind of very specific brain surgery, and give them a pre- and post- rationality test.
At this point I was mostly wondering if there were any motivating anecdotes such as Phineas Gage or gourmand syndrome, except with a noticeable personality change towards rationality. Someone changing his political orientation, becoming less superstitious, or gambling less as a result of an injury could be useful (and, as a caveat, all could be caused by damage that has nothing to do with rationality).
and even then you would only expect 1 in 50 or so kinds of brain surgery to remove the part that caused (say) motivated cognition, and only one in 5 or so of those to not do so much damage that you could actually detect the positive effect.
Better, use high-precision real-time brain imaging to image somebody’s brain when motivated cognition is happening, then use high-precision TMS to switch just that part off.
This is what I meant about quantifying the probability estimate before clarifying the exact question. As I said originally, I’m skeptical of a strong heritability for rationality independent of IQ. I’m not sure what the correct statistical terminology is for talking about this kind of question. I think there is a low probability that a targeted genetic modification could increase rationality independent of IQ in a significant and measurable way. That belief doesn’t map in a straightforward way onto a claim about the heritability of rationality. I’m expecting What Intelligence Tests Miss to help clarify my thinking about what kind of test could even be used to reliably separate a ‘rationality’ cognitive trait from IQ which would be a necessary precondition to measuring the heritability of rationality.
These all correlate significantly with IQ however I believe (correct me if you think I’m wrong on this). It’s at least plausible that targeted genetic modifications could improve say spatial or verbal reasoning significantly more than IQ (perhaps by lowering scores in other areas) since there is some evidence of sex differences in these traits. Rationality seems more like a way of reasoning and a higher level trait than these ‘specialized’ forms of intelligence however.
Maybe. Actually, I think that the dominant theory around here is that rationality is actually the result of an atrophied motivated-cognition module, so perfect rationality is not a question of creating a new brain module, but subtracting off the distorting mechanisms that we are blighted with.
I realize that “brain module” != “distinct patch of cortex real estate”, but have there been any cases of brain damage that have increased a person’s rationality in some areas?
I am aware that depression and certain autism spectrum traits have this property, but I’m curious if physical trauma has done anything similar.
I don’t know, but without a standardized test for rationality (like there is for IQ), how would we even notice?
Googling for “can brain injury cause autism” leads to conflicting info:
To test this, you’d need to somehow identify a group of patients that were going to receive some kind of very specific brain surgery, and give them a pre- and post- rationality test.
At this point I was mostly wondering if there were any motivating anecdotes such as Phineas Gage or gourmand syndrome, except with a noticeable personality change towards rationality. Someone changing his political orientation, becoming less superstitious, or gambling less as a result of an injury could be useful (and, as a caveat, all could be caused by damage that has nothing to do with rationality).
This paper on schizophrenia is interesting.
...because of the following insights ____.
and even then you would only expect 1 in 50 or so kinds of brain surgery to remove the part that caused (say) motivated cognition, and only one in 5 or so of those to not do so much damage that you could actually detect the positive effect.
Better, use high-precision real-time brain imaging to image somebody’s brain when motivated cognition is happening, then use high-precision TMS to switch just that part off.