In the Solidarity Game (Selten and Ockenfels, 1998), two "rich" persons can support a "poor" one. A strong positive correlation between one rich person's solidarity contribution and his expected contribution of the other is observed. This paper investigates the causality behind this correlation....

For many people "solidarity" has become a meaningless word used in slogans - too often used without leading to any economic consequences. We show in this paper conditions under which solidarity can be a powerful instrument. In a solidary action, an individual in a group contributes to a series...

Most incomes underlie some risk, i.e. ex ante they can be regarded as a lottery ticket. In every society, the lucky winners of this lottery compensate unlucky losers (unemployed workers or bankrupt entrepreneurs) privately and/or by public insurances. Do voluntary solidarity payments depend on...