Political scientists and economists commonly test for different kinds of social influence on collective action, particularly social pressure (visibility) and social information about the contributions of others (leading to conditional cooperation) but rarely in the same study design. This paper assesses the relative effect of these two kinds of social influence suggesting that their impact is best understood through hypothesizing for heterogeneous treatment effects based on personality.

We will begin a new three-year research programme on The Internet, Public Policy and Political Science: Collective Action, Governance and Citizen-Government Interactions in the Digital Era starting 1st April.

More information about this project is available in the OII press release, and project description page.

This paper tests the hypothesis that social information provided by the internet makes it possible in large groups to exert social pressure that Olson considered viable only for smaller groups. In two experiments - laboratory and field - subjects could choose to sign petitions and donate money to support causes. Participants were randomised into treatment groups that received varying information about how many other people had participated and control groups receiving no social information.

The shift of much of political life on to the Internet and WWW has implications for understanding of political behaviour, particularly people's willingness to undertake collective action and organise around public goods. Web-based experiments are an under-used methodology to identify and investigate these Internet effects.