Mobile phones and core network growth in Kenya: Strengthening weak ties

In contrast to recent US studies showing a decrease in core network size, our Kenyan data reveals substantial network growth. We attribute this to the diffusion of mobile telephones. Results from pooled survey data from Nairobi professionals and entrepreneurs in 2002 and 2007 as well as qualitative interviews from 2007 to 2009 show virtual saturation in the diffusion of phones during this period, but no direct effect of technology use. What explains this puzzle is a network effect of mobile telephony: increased technological access to existing networks in a context of resource scarcity leads to a strengthening of weak ties and the enhancement of core networks among Kenyans. Video ethnographic data before and after the 2007 post-election unrest supports this interpretation, showing that mobile phones are a crucial resource in managing interpersonal networks for instrumental purposes.