Much of it is related to lead poisoning. Excellent references to demonstrate
this are below. This is pure science, no exaggeration.
Crowding in areas where leaded petrol is used leads very quickly to higher
atmospheric lead and to increased blood lead levels. Lead in children is
extremely strongly associated with antisocial and delinquent behaviour.
These children have been followed up longitudinally from preschool to jail.
Thankfully the USA has addressed the lead issue very well.  Other countries
are a long way behind. Now the USA is rewarded by a big drop in violent
crime.
Refs:
1/ Rachel's Environment & Health Weekly no's 529,318,294,214,189,3.
http://www.monitor.net/rachel/rehw-index.html
2/ Needleman, Herbert L. et al, "Bone Lead Levels and Delinquent Behavior,"
JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Vol. 275, No. 5 (February 7,
1996), pgs. 363-369
3/ Committee on Environmental Health, American Academy of Pediatrics, "Lead
Poisoning: From Screening to Primary Prevention," PEDIATRICS Vol. 92 (July
1993), pgs. 176-183
4/ Alan L. Mendelsohn, Benard P. Dreyer, Arthur H. Fierman, Carolyn M.
Rosen, Lori A. Legano, Hillary A. Kruger, Sylvia W. Lim, and Cheryl D.
Courtlandt "Low-Level Lead Exposure and Behavior in Early Childhood"
Pediatrics 1998; 101: e10. http://intl.pediatrics.org/content/vol101/issue3/
PEDIATRICS often has articles on lead poisoning.

----- Original Message -----
From: Erik Hill <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, November 28, 1999 10:19 AM
Subject: [P-F] population and violence


> I'm not sure if I already posted this, but didn't see it replyed to nor
did I
> see it get sent back to me (all my other posts do -- I'm set to retreive
my own
> postings as well) so I'll post it again.
>
> I've done some research on the web which has convinced me that the greater
a
> population of a city is, the greater the violent crime rate is
> (crimes/100000/year).  I see this also as a paleolithic maladaptation - we
are
> poorly adapted to being crowded.  Any ideas?
>
> Erik