This paper deals with the topic of cooperation among economic agents in a repeated game with unknown length. There is still
little empirical evidence why and under which conditions people cooperate at all in situations such as the prisoner’s dilemma
game (PDG). There is extensive literature on the theory of infinitely repeated games and also a large number of explanations
for cooperative behaviour. Experimental evidence on the question how future features will affect the behaviour is rare and
the classification of the participants into social and selfish oriented types is new in this context.
Modern contract theory deals a lot with the willingness to cooperate. Therefore we raise the question under which conditions
cooperation is created in special economic situations (for example in energy contracts).
The present study examines the influence of pre-existing individual differences in social value orientations measured by the
outcomes to oneself and others according to the ring measure by McClintock [10]. We run an experiment in the lab and we are
able to figure out the high percentage at cooperation in a PDG in which the number of future rounds is unknown and the fact
that cooperation is significantly dependent on the type of the subjects’ social value orientation.