This book is the product of an intensive cooperation between psych- ogists and sociologists who study solidarity and prosocial behavior, and its fruits are briefly summarized in Chapter 1. The topics of so- darity and prosocial behavior are at the core of both disciplines and thus one might expect that an intensive cooperation like the one that produced this book is not uncommon. Surprisingly however, it is extremely rare that sociologists and psychologists get together to c- bine their knowledge in these fields. Instead, researchers from both disciplines tend to ignore each other s work...

This book constitutes the proceedings of the 4th International Conference on Social Informatics, SocInfo 2012, held in Lausanne, Switzerland, in December 2012. The 21 full papers, 18 short papers included in this volume were carefully reviewed and selected from 61 submissions. The papers are organized in topical sections named: social choice mechanisms in the e-society, computational models of social phenomena, social simulation, web mining and its social interpretations, algorithms and protocols inspired by human societies, socio-economic systems and applications, trust, privacy, risk and...