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The lead exposure angle and the removal of lead in gasolines needs more weight than the throwaway mention it was given. Simple biology is a ludicrously heavy l

The lead exposure angle and the removal of lead in gasolines needs more weight than the throwaway mention it was given. Simple biology is a ludicrously heavy lever on human behavior.

IndianAstronaut 12y ago
>Simple biology is a ludicrously heavy lever on human behavior. Seemingly small biological factors can have huge social consequences. For example not having clean water and getting parasites can mean a lower IQ for children and hindered development. http://www.economist.com/node/16479286 http://www.economist.com/node/16479286
- new299 12y ago
  The article makes that assertion, and implies that their is more evidence beyond correlation, but never shows this. Clean water, is likely to be so highly correlated with IQ due to any number of other factors I think it will be extremely difficult to disambiguate.
  - IndianAstronaut 12y ago
    It might likely be a causal factor. http://repository.unm.edu/bitstream/handle/1928/17471/CEppig%20Dissertation.pdf?sequence=1#page=75 http://repository.unm.edu/bitstream/handle/1928/17471/CEppig...
    - new299 12y ago
      Could be, but I don't think the report shows that. In fact it states: "Many scientists, both critics and supporters, have expressed concern that the experimental methods we have used have not adequately established that causation exists between IQ and infectious disease, and that its direction is the one we predict. The use of longitudinal studies could answer all of these questions. Such studies would track children from as early an age as possible, documenting the intensity, duration, timing, and types of infections they acquire, and track their cognitive development through the use of culturally-appropriate IQ tests." In fact I'd think that so many other potential causative factors, such as lack of education, freetime, skilled employment etc. are likely to be correlated with incidence of infectious disease, that it's hard to draw any strong conclusions without a more detailed study.
- BorisMelnik 12y ago
  I heard a really good TED talk about this recently. and it was about mold / pollution in LA. It gave the example of a young woman who came into a hospital multiple times for a headache, and could not get to the root of the problem. Eventually she saw a specialist and attributed 100% of the cause to the fact that she lived in East LA, had rat droppings, mold in her house which was the cause.
InclinedPlane 12y ago
I sort of buy the lead theory, up to a point. It's unhelpful (from a statistical point of view) that the elimination of lead from gasoline occurred around the same time as the crack epidemic started to wane.
- pgeorgi 12y ago
  I think the elimination of lead from gasoline happened at different points in time in different countries. unless they all had a similarly timeshifted crack epidemic (and of the same magnitude), that might help sorting things out. (also: maybe crack use is a result of a violent environment, thus the causality chain could be lead -> violence -> crack - assuming there is any causality between any of these)
  - InclinedPlane 12y ago
    The violence from the crack epidemic wasn't because people were using crack (crackheads don't commit a ton of murders, really) it was because there was sort of a "land grab" for new crack dealers resulting in a lot of turf wars until the situation stabilized and/or communities got fed up by the gang violence. The reason why the crack epidemic reasoning makes more sense as a causitive agent is because violent crime didn't simply go down in the '90s as leaded gasoline was phased out. Rather, crime increased dramatically in the '80s and early '90s before peaking and falling. That doesn't match either the profile of lead exposure nor the population of the folks who typically commit violent crimes (sub 30 year old males). In fact, there was a peak of violent crime among 14-24 year olds as a percentage of that population group that matches the onset of the crack epidemic perfectly but does not match lead exposure or socio-economic status well at all. Here's a good graph that highlights just that: http://en.wikipedia.org/wiki/Gun_violence_in_the_United_States#mediaviewer/File:Homoffendersbyage.svg http://en.wikipedia.org/wiki/Gun_violence_in_the_United_Stat... The figures there back up the premise that there was a wave of new and exceptional violence caused by young gang bangers fighting in the streets over the crack business.
  - hudibras 12y ago
    The shift in the crime rates does appear to track childhood lead levels across countries with different dates of leaded gas elimination. See Figures 7 and 8 in this paper. http://pic.plover.com/Nevin/Nevin2007.pdf http://pic.plover.com/Nevin/Nevin2007.pdf

The lead exposure angle and the removal of lead in gasolines needs more weight than the throwaway mention it was given. Simple biology is a ludicrously heavy lever on human behavior.

IndianAstronaut 12y ago

>Simple biology is a ludicrously heavy lever on human behavior. Seemingly small biological factors can have huge social consequences. For example not having clean water and getting parasites can mean a lower IQ for children and hindered development. http://www.economist.com/node/16479286 http://www.economist.com/node/16479286

new299 12y ago
The article makes that assertion, and implies that their is more evidence beyond correlation, but never shows this. Clean water, is likely to be so highly correlated with IQ due to any number of other factors I think it will be extremely difficult to disambiguate.
- IndianAstronaut 12y ago
  It might likely be a causal factor. http://repository.unm.edu/bitstream/handle/1928/17471/CEppig%20Dissertation.pdf?sequence=1#page=75 http://repository.unm.edu/bitstream/handle/1928/17471/CEppig...
  - new299 12y ago
    Could be, but I don't think the report shows that. In fact it states: "Many scientists, both critics and supporters, have expressed concern that the experimental methods we have used have not adequately established that causation exists between IQ and infectious disease, and that its direction is the one we predict. The use of longitudinal studies could answer all of these questions. Such studies would track children from as early an age as possible, documenting the intensity, duration, timing, and types of infections they acquire, and track their cognitive development through the use of culturally-appropriate IQ tests." In fact I'd think that so many other potential causative factors, such as lack of education, freetime, skilled employment etc. are likely to be correlated with incidence of infectious disease, that it's hard to draw any strong conclusions without a more detailed study.
BorisMelnik 12y ago
I heard a really good TED talk about this recently. and it was about mold / pollution in LA. It gave the example of a young woman who came into a hospital multiple times for a headache, and could not get to the root of the problem. Eventually she saw a specialist and attributed 100% of the cause to the fact that she lived in East LA, had rat droppings, mold in her house which was the cause.

InclinedPlane 12y ago

I sort of buy the lead theory, up to a point. It's unhelpful (from a statistical point of view) that the elimination of lead from gasoline occurred around the same time as the crack epidemic started to wane.

pgeorgi 12y ago
I think the elimination of lead from gasoline happened at different points in time in different countries. unless they all had a similarly timeshifted crack epidemic (and of the same magnitude), that might help sorting things out. (also: maybe crack use is a result of a violent environment, thus the causality chain could be lead -> violence -> crack - assuming there is any causality between any of these)
- InclinedPlane 12y ago
  The violence from the crack epidemic wasn't because people were using crack (crackheads don't commit a ton of murders, really) it was because there was sort of a "land grab" for new crack dealers resulting in a lot of turf wars until the situation stabilized and/or communities got fed up by the gang violence. The reason why the crack epidemic reasoning makes more sense as a causitive agent is because violent crime didn't simply go down in the '90s as leaded gasoline was phased out. Rather, crime increased dramatically in the '80s and early '90s before peaking and falling. That doesn't match either the profile of lead exposure nor the population of the folks who typically commit violent crimes (sub 30 year old males). In fact, there was a peak of violent crime among 14-24 year olds as a percentage of that population group that matches the onset of the crack epidemic perfectly but does not match lead exposure or socio-economic status well at all. Here's a good graph that highlights just that: http://en.wikipedia.org/wiki/Gun_violence_in_the_United_States#mediaviewer/File:Homoffendersbyage.svg http://en.wikipedia.org/wiki/Gun_violence_in_the_United_Stat... The figures there back up the premise that there was a wave of new and exceptional violence caused by young gang bangers fighting in the streets over the crack business.
- hudibras 12y ago
  The shift in the crime rates does appear to track childhood lead levels across countries with different dates of leaded gas elimination. See Figures 7 and 8 in this paper. http://pic.plover.com/Nevin/Nevin2007.pdf http://pic.plover.com/Nevin/Nevin2007.pdf