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> While it can be shown that a majority of psychopathic serial killers have the prefrontal cortex brain anomaly, it's also the case that almost all such crimina

> While it can be shown that a majority of psychopathic serial killers have the prefrontal cortex brain anomaly, it's also the case that almost all such criminals are male. Yet we have an abundance of plainly apparent counterexamples to dismiss the idea that being male implies criminality That's a bloody weird argument, and AFAICS wrong: (psychopath -> male) /-> (male -> psychopath), where -> is logical implication and /-> is is 'does not imply'. You are confusing implication with equality. > with more research possessing the same systematic error ... in spite of a counterexample What systematic error? What counterexample? > without a thorough and unbiased analysis of the rest of the population Sampling not good enough? Serious question, do you have any background in either classical logic or statistics? And what is your area of research?

soreine 7y ago
It seems there's a misunderstanding. According to me you are actually pointing to the same logical fallacy. The systematic error is indeed to think that correlation does imply causality. There's no more reason to think prefontal cortex anomaly causes psychopathy than being male does.
- gnode 7y ago
  Indeed. Thanks for putting this more succinctly than I did. I'd add that it's easier to observe the logical fallacy in the case of being male, because half of people are male, and being male is obvious. The occurrence of the PFC abnormality is much smaller, and we don't tend to see people's brains, so it's much harder to point to the counterexamples.
- tempguy9999 7y ago
  > think that correlation does imply causality You know, despite the trope sometimes it does. Does it here? From wikipedia <https://en.wikipedia.org/wiki/Psychopathy> https://en.wikipedia.org/wiki/Psychopathy>: Blair, a researcher who pioneered research into psychopathic tendencies stated, “With regard to psychopathy, we have clear indications regarding why the pathology gives rise to the emotional and behavioral disturbance and important insights into the neural systems implicated in this pathology”. From the same wiki article Researchers have linked head injuries with psychopathy and violence. Since the 1980s, scientists have associated traumatic brain injury, such as damage to the prefrontal cortex, including the orbitofrontal cortex, with psychopathic behavior and a deficient ability to make morally and socially acceptable decisions, a condition that has been termed "acquired sociopathy", or "pseudopsychopathy".[72] Individuals with damage to the area of the prefrontal cortex known as the ventromedial prefrontal cortex show remarkable similarities to diagnosed psychopathic individuals, displaying reduced autonomic response to emotional stimuli, deficits in aversive conditioning, similar preferences in moral and economic decision making, and diminished empathy and social emotions like guilt or shame > There's no more reason to think prefontal cortex anomaly causes psychopathy than being male does. It seems experts think otherwise.
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?

soreine 7y ago

It seems there's a misunderstanding. According to me you are actually pointing to the same logical fallacy. The systematic error is indeed to think that correlation does imply causality. There's no more reason to think prefontal cortex anomaly causes psychopathy than being male does.

gnode 7y ago
Indeed. Thanks for putting this more succinctly than I did. I'd add that it's easier to observe the logical fallacy in the case of being male, because half of people are male, and being male is obvious. The occurrence of the PFC abnormality is much smaller, and we don't tend to see people's brains, so it's much harder to point to the counterexamples.
tempguy9999 7y ago
> think that correlation does imply causality You know, despite the trope sometimes it does. Does it here? From wikipedia <https://en.wikipedia.org/wiki/Psychopathy> https://en.wikipedia.org/wiki/Psychopathy>: Blair, a researcher who pioneered research into psychopathic tendencies stated, “With regard to psychopathy, we have clear indications regarding why the pathology gives rise to the emotional and behavioral disturbance and important insights into the neural systems implicated in this pathology”. From the same wiki article Researchers have linked head injuries with psychopathy and violence. Since the 1980s, scientists have associated traumatic brain injury, such as damage to the prefrontal cortex, including the orbitofrontal cortex, with psychopathic behavior and a deficient ability to make morally and socially acceptable decisions, a condition that has been termed "acquired sociopathy", or "pseudopsychopathy".[72] Individuals with damage to the area of the prefrontal cortex known as the ventromedial prefrontal cortex show remarkable similarities to diagnosed psychopathic individuals, displaying reduced autonomic response to emotional stimuli, deficits in aversive conditioning, similar preferences in moral and economic decision making, and diminished empathy and social emotions like guilt or shame > There's no more reason to think prefontal cortex anomaly causes psychopathy than being male does. It seems experts think otherwise.

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?