3 ms·

> You are confusing implication with equality. No, I'm not. This is the very point I was making. I was using the example (psychopath -> male) ^ !(male -> psych

by gnode 7y ago

> You are confusing implication with equality. No, I'm not. This is the very point I was making. I was using the example (psychopath -> male) ^ !(male -> psychopath) to show how deducing (abnormal brain -> psychopath) from (psychopath -> abnormal brain) is flawed. Perhaps I made this confusing with my tangential remark about the amygdala connection. > What systematic error? The systematic error of deducing a causality from correlation with under-sampling, in the aforementioned way the brain abnormality was determined to imply psychopathy despite neglecting to significantly sample occurrences of people with the prefrontal cortex abnormality in the non-murderous population. > Sampling not good enough? The sample has to be meaningful. If you find that everyone in the extremely rare serial killer group has a particular brain abnormality, you can't deduce that the brain abnormality causes their behaviour (rather than simply being prerequisite), without proving that this brain abnormality does not occur benignly within the non-serial killer population (to a significant degree). Because serial-killers are very rare (as far as we can observe), the sample of the remaining population would need to be very large. If we were to sample such a large portion of the population as we would need to probabilistically rule out a given proportion of those with the abnormality being benign social individuals, then that would be convincing. > Serious question [...] Yes; computer science.

tempguy9999 7y ago
Oh boy, I regret posting this, however down the rabbit hole we go... > (psychopath -> male) ^ !(male -> psychopath) I don't know what ^ means here, and !(m->p) is very different from (m/->p) > to show how deducing (abnormal brain -> psychopath) from (psychopath -> abnormal brain) is flawed. Is it? From <https://psychcentral.com/news/2012/05/11/scans-show-psychopaths-have-brain-abnormalities/38540.html> https://psychcentral.com/news/2012/05/11/scans-show-psychopa... “Using MRI scans we found that psychopaths had structural brain abnormalities in key areas of their ‘social brains’ compared to those who just had ASPD,” he said. He noted there is a clear difference between those with ASPD and those with ASPD+P. “We describe those without psychopathy as hot-headed and those with psychopathy as cold-hearted,” he said. “The cold-hearted psychopathic group begin offending earlier, engage in a broader range and greater density of offending behaviors, and respond less well to treatment programs in adulthood, compared to the hot-headed group. We now know that this behavioral difference corresponds to very specific structural brain abnormalities which underpin psychopathic behavior [my emphasis], such as profound deficits in empathizing with the distress of others.” The researchers used magnetic resonance imaging (MRI) to scan the brains of 44 violent offenders diagnosed with ASPD. Crimes committed included murder, rape, attempted murder and grievous bodily harm. Of these, 17 met the diagnosis for psychopathy (ASPD+P) and 27 did not. Those that met the antisocial personality disorder but did not meet the psychopathy criteria (via the Psychopathy Checklist) were referred to as the ASPD-P group by the researchers. They also scanned the brains of 22 healthy non-offenders. So they found a link, causal or not, between abnormalities and psychopathy, and they had a control group too. > The systematic error of deducing a causality from correlation with under-sampling I grant the control group here is small, but for you to claim it's 'under-sapled' is a bit cheeky. There seem to have been other studies too, from wikipedia "Blair, R. J. R. (2003). "Neurobiological basis of psychopathy". The British Journal of Psychiatry. 182 (1): 5–7. doi:10.1192/bjp.182.1.5. PMID 12509310." My guess is these people aren't so stupid as to overlook issues of under-sampling and mistaking correlation with causation. > If you find that everyone in the extremely rare serial killer group has a particular brain abnormality [...] As serial-killers are very rare (as far as we can observe), the sample of the remaining population would need to be very large. True, but psychopaths are neither rare nor automatically serial killers. If you're not equating them why did you mention serial killers?
- gnode 7y ago
  > I don't know what ^ means here Logical conjugation ("and"). I should have used ¬ instead of ! to have been more conventional. > Is it [flawed to deduce (abnormal brain -> psychopath) from (psychopath -> abnormal brain)]? Yes. That they show the group has a brain anomaly, and hypothesise a mechanism which links it to the behaviour is not enough. It's plausible that people who possess this brain abnormality within the rest of the population commonly are not psychopaths. You aren't going to find that within "22 healthy non-offenders", the sample is too small. > So they found a link, causal or not, between abnormalities and psychopathy I don't dispute this. > There seem to have been other studies too, from wikipedia "Blair, R. J. R. (2003). "Neurobiological basis of psychopathy". They aren't making the conclusion that the brain anomaly implies psychopathy, they only theorise a biological basis for it being foundational. Furthermore their article they states: "However, all of these studies, with the exception of one by (Raine et al, 2000), have been with violent offenders rather than individuals with psychopathy. [...] Indeed, neuropsychological work with individuals with psychopathy, unlike work with individuals who are violent, has repeatedly found frontal functioning to be intact (Kandel & Freed, 1989)." This gives more weight to the argument that it is flawed to make deductions primarily by studying incarcerated offenders. Neuropsychological studies are often compromising. Scanning brains is expensive. I don't believe that these researchers are stupid, as you asked, but it would be silly to say that scientists never theorise without concrete proof. Neurobiology is still highly hypothetical, and experiments are often very limited by practical and ethical concerns. > why did you mention serial killers? From the Smithsonian article: "neuroscientist James Fallon was looking at brain scans of serial killers."

by gnode 7y ago

tempguy9999 7y ago

Oh boy, I regret posting this, however down the rabbit hole we go... > (psychopath -> male) ^ !(male -> psychopath) I don't know what ^ means here, and !(m->p) is very different from (m/->p) > to show how deducing (abnormal brain -> psychopath) from (psychopath -> abnormal brain) is flawed. Is it? From <https://psychcentral.com/news/2012/05/11/scans-show-psychopaths-have-brain-abnormalities/38540.html> https://psychcentral.com/news/2012/05/11/scans-show-psychopa... “Using MRI scans we found that psychopaths had structural brain abnormalities in key areas of their ‘social brains’ compared to those who just had ASPD,” he said. He noted there is a clear difference between those with ASPD and those with ASPD+P. “We describe those without psychopathy as hot-headed and those with psychopathy as cold-hearted,” he said. “The cold-hearted psychopathic group begin offending earlier, engage in a broader range and greater density of offending behaviors, and respond less well to treatment programs in adulthood, compared to the hot-headed group. We now know that this behavioral difference corresponds to very specific structural brain abnormalities which underpin psychopathic behavior [my emphasis], such as profound deficits in empathizing with the distress of others.” The researchers used magnetic resonance imaging (MRI) to scan the brains of 44 violent offenders diagnosed with ASPD. Crimes committed included murder, rape, attempted murder and grievous bodily harm. Of these, 17 met the diagnosis for psychopathy (ASPD+P) and 27 did not. Those that met the antisocial personality disorder but did not meet the psychopathy criteria (via the Psychopathy Checklist) were referred to as the ASPD-P group by the researchers. They also scanned the brains of 22 healthy non-offenders. So they found a link, causal or not, between abnormalities and psychopathy, and they had a control group too. > The systematic error of deducing a causality from correlation with under-sampling I grant the control group here is small, but for you to claim it's 'under-sapled' is a bit cheeky. There seem to have been other studies too, from wikipedia "Blair, R. J. R. (2003). "Neurobiological basis of psychopathy". The British Journal of Psychiatry. 182 (1): 5–7. doi:10.1192/bjp.182.1.5. PMID 12509310." My guess is these people aren't so stupid as to overlook issues of under-sampling and mistaking correlation with causation. > If you find that everyone in the extremely rare serial killer group has a particular brain abnormality [...] As serial-killers are very rare (as far as we can observe), the sample of the remaining population would need to be very large. True, but psychopaths are neither rare nor automatically serial killers. If you're not equating them why did you mention serial killers?

gnode 7y ago
> I don't know what ^ means here Logical conjugation ("and"). I should have used ¬ instead of ! to have been more conventional. > Is it [flawed to deduce (abnormal brain -> psychopath) from (psychopath -> abnormal brain)]? Yes. That they show the group has a brain anomaly, and hypothesise a mechanism which links it to the behaviour is not enough. It's plausible that people who possess this brain abnormality within the rest of the population commonly are not psychopaths. You aren't going to find that within "22 healthy non-offenders", the sample is too small. > So they found a link, causal or not, between abnormalities and psychopathy I don't dispute this. > There seem to have been other studies too, from wikipedia "Blair, R. J. R. (2003). "Neurobiological basis of psychopathy". They aren't making the conclusion that the brain anomaly implies psychopathy, they only theorise a biological basis for it being foundational. Furthermore their article they states: "However, all of these studies, with the exception of one by (Raine et al, 2000), have been with violent offenders rather than individuals with psychopathy. [...] Indeed, neuropsychological work with individuals with psychopathy, unlike work with individuals who are violent, has repeatedly found frontal functioning to be intact (Kandel & Freed, 1989)." This gives more weight to the argument that it is flawed to make deductions primarily by studying incarcerated offenders. Neuropsychological studies are often compromising. Scanning brains is expensive. I don't believe that these researchers are stupid, as you asked, but it would be silly to say that scientists never theorise without concrete proof. Neurobiology is still highly hypothetical, and experiments are often very limited by practical and ethical concerns. > why did you mention serial killers? From the Smithsonian article: "neuroscientist James Fallon was looking at brain scans of serial killers."