Murders in low-IQ neighborhoods

Reuters reports:

A murder in the neighborhood can significantly knock down a child's score on an IQ test, even if the child did not directly witness the killing or know the victim, U.S. researchers reported on Monday.

The findings have implications both for crime control efforts and for the heavy reliance on standardized tests, said New York University sociology professor Patrick Sharkey, who conducted the study.

They can also explain about half the achievement gap between blacks and whites on such tests, he reported in the Proceedings of the National Academy of Sciences. ...

In general, black U.S. children score about one standard deviation lower on standardized tests than white children. This finding accounts for half that difference, Sharkey said. ...

It is well documented that blacks are far more likely to be murdered than members of any other U.S. ethnic group -- murder is the most common cause of death for young black men.

Sharkey said the findings also have implications for IQ tests, which are supposed to be neutral assessments of ability.

"These tests are not purely capturing some underlying intelligence," he said.

So he found a correlation between high murder rates and low IQ rates in neighborhoods. Possible explanations include (1) low IQ causes people to commit murder, (2) murder causes people a few blocks away to have low IQ, and (3) both are byproducts of black neighborhoods. Which seems more plausible to you? The sociology prof chooses option (2). Apparently that is the only option permitted by his research focus:

Patrick Sharkey will join NYU's Department of Sociology ... His research focuses on various issues related to inequality in urban neighborhoods. One strand of research seeks to describe and explain the persistence of neighborhood inequality in Americas cities, and the mechanisms by which this inequality persists over time and across generations of family members. A second strand of his work focuses on the consequences of persistent neighborhood inequality for the life chances of individuals from different racial and ethnic groups in America.

There is more discussion here.