I&#x27;m not surprised.  Any time I see a research paper that suggests a highly complex issue, like crime, can be neatly explained by a single variable, my BS meter goes off.<p>Could a reduction in lead levels contribute to the drop in crime?  Sure, but any effect would likely be drowned out by the multitude of other changes that have happened over the past 60+ years.<p>I&#x27;m not sure what it is, but humans seem to be highly suceptable to simple explanations for the world.  If you need some examples, just browse snopes.com