[Alex3917]

I'm not an expert on this, but here is a link to one of the studies:

http://csp.org/experience/docs/hood_dimensions.html

If you went and searched Google Scholar or JSTOR I'm sure you could find the rest of the papers based on that. I'm pretty sure that Roland Griffiths also mentions it here:

http://premium.gnosticmedia.podomatic.com/entry/2009-01-11T2...