More on contagions...

Just summarizing a great paper that combines social network data and co-location data: "Distinguishing between Drivers of Social Contagion: Insights from Combining Social Network and Co-location Data".

The field now seems ready to move from investigating whether contagion is really at work to why it occurs (Aral 2011; Godes 2011; Iyengar et al. 2011b).

Social contagion may occur for at least five reasons:
1. The process may operate through spreading awareness and interest,
2. Through social learning about the new product’s risks and benefits,
3. Through social-normative influence increasing the legitimacy of the new product,
4. Through concerns that not adopting may result in a competitive or status disadvantage, or
5. Through direct and indirect “network” or installed base effects (Van den Bulte and Lilien 2001).

Who is prone to influence: "Physicians who perceive themselves to be opinion leaders are less sensitive to peer behavior whereas true sociometric leaders are not. This finding indicates that self-confidence rather than true expertise moderates sensitivity to contagion, which is consistent with risk reduction as well as status maintenance mechanisms but not with awareness (e.g., Berger and Heath 2008; Van den Bulte and Stremersch 2004)."

Product-type-specific influence: "what drives contagion is to consider characteristics of the product, and possibly also the influencers. For instance, for products that do not benefit from standard marketing communication and present little perceived risk, contagion may foster adoption by operating at the awareness stage. In such cases, occasional users may be more effective in creating additional awareness than regular users. This is because the latter are more likely to be connected to other regular users and others who are already aware of the product, as noted in a study by Godes and Mayzlin (2009) of stimulated word of mouth for a restaurant chain"

Paper conclusion: "spatial structure overlaps little with network structure, which is why contagion from co-located peers can provide information over and above what can be gleaned from contagion from network peers"

Information-type-specific influence: "Some information and knowledge is quite complex and possibly even tacit. It is hard to convey through “lean” channels such as written documents and presentations at conferences by high-profile speakers, and typically requires “richer” channels, esp. face-to-face interaction (Daft and Lengel 1986)"