[A socio-relational basis of "irrational" cooperation: an experimental study with the selective-play paradigm]

Experimental gaming researchers have recently realized that a larger context is important in which dyadic prisoner's dilemma (PD) relations are embedded. The main purpose of this study was to examine whether people facing a "selective-play" situation spontaneously adopt the out-for-tat strategy (OFT), which previous studies found the most effective in such a situation. OFT proscribes to (1) always cooperate, (2) keep playing with the current player as long as he/she cooperates, and (3) desert the partner as soon as he/she stops cooperating. Results of an experiment with 90 students, of groups of six or eight, showed that subjects who faced a high level of social uncertainty in fact spontaneously adopted the strategy, interacting with the same partner as long as he/she cooperated, and exiting from the relation when the partner defected. Subjects who faced a low level of social uncertainty kept only the third part of the strategy, leaving the relation with a defector, but not necessarily keeping interaction with a cooperative partner.