‘In Social Networks, Group Boundaries Promote the Spread of Ideas, Penn Study Finds’, http://www.upenn.edu/pennnews/news/social-networks-group-boundaries-promote-spread-ideas-penn-study-finds, THE UNIVERSITY OF PENNSYLVANIA (June 22, 2015).

Group Boundaries

There’s a belief that the more that people interact with strangers, the more that new ideas and beliefs will spread. (…) What this study shows is that preserving group boundaries is actually necessary for complex ideas to become accepted across diverse populations.