Transparency, Cambridge, Massachusetts, Cambridge University Press. 16 Wu, F & Huberman, B.A. 2007 Novelty and collective action Proc. Natl. Acad. Set U.S.A. 104, 17599 — 17601. (doi: 10.1073/pnas.0704916104) Figure caption: Average group contributions for each treatment: shame, honour, control. In the sh