I grew up in Côte-des-Neiges, an ethnically-diverse neighborhood of Montréal, and ended up with a PhD (as well as a collection of other degrees), so there might be some truth to this. 🙂
From http://ow.ly/Klkri– Co.Design:
Another Reason To Live In A Diverse Neighborhood: It Could Make Your Kids Smarter
Babies who hear different languages around town may be more open-minded about who they learn from.