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....

The 2002 prices of suppliers in German call-by-call telephone market are rather dispersed, out-of-phase (uncorrelated), and show systematic down-up movements. In 2004, these prices are less dispersed, more in-phase and show more upwards runs than downs-ups. In both years, we clearly do not...

Models to the issue of altruism which rely on externalities of well-being are rarely used explicitly. In this paper we compare such utility-based approaches with the standard approach on altruism which is based on externalities of income. Testable differences of both types of models are derived...

In Dictator Game experiments where the information status of the recipient varies we find that a certain type of donator tends to reduce his offer when the recipient has incomplete information about the pie size. This result provides new evidence on those approaches on altruism, which assume...

For many people solidarityʺ 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 of...