9
Findings
Table 1 shows that subjects were more willing to accept the risky PD game, and to
reject the certain “no play” payoff, in the domain of losses than in the domain of gains.
Although payoffs from the game and from the "no play" option were equivalent across
the two conditions, subjects chose the PD game in preference to the certain payoff in
80% of the losses encounters but in only 57% of the gains encounters.
(Table 1 about here)
Consistent with the dominance of defection in the PD, the incidence of
cooperating in joined games was low. The incidence of cooperation, however, was
essentially the same across the two frames (36% in gains, 35% in losses), consistent
with the possibility that intending co-operators and intending defectors responded to the
frame manipulation in the same way. Also consistent with that possibility, Table 2
shows that there is little difference between the number of “play and cooperate” choices
subjects made in the two frames.
(Table 2 about here)
Finally, and allowing for the 10-point starting endowment in the losses condition,
average payoffs for all subjects who joined PD games were 4.57 and 4.52 in the gains
and losses conditions, respectively. The marked bias toward entering PD games in the
domain of losses was, therefore, not justified by any greater returns subjects reaped
from acting on that bias.
Discussion
Convention