Altruistic punishment - the punishment of norm violators at one's own cost without material benefit - is frequently observed in experimental economics, field studies and in people's everyday life. The existence of this ostensibly irrational behavior is often linked to other-regarding preferences...

We introduce the concept of “negative bubbles” as the mirror image of standard financial bubbles, in which positive feedback mechanisms may lead to transient accelerating price falls. To model these negative bubbles, we adapt the Johansen-Ledoit-Sornette (JLS) model of rational expectation...

We review the “social bubble” hypothesis, which holds that strong social interactions between enthusiastic supporters of new ventures weave a network of reinforcing feedbacks that lead to a widespread endorsement and extraordinary commitment by those involved in the projects, beyond what...