Discussion Papers 745
5 Experimental results
In the beginning of a session, the participants were randomly and anonymously assigned into
four two-player groups, and, in the ASYM treatments, they were also randomly allocated the
role of either a low-cost or a high-cost player for the entire experiment.
Participants received written instructions (an English translation can be found in the Appen-
dix, the French version is available upon request), which were also read aloud to them. Before
the experiment could start, each participant had to provide correct answers to a number of
questions regarding the understanding of the instructions. Participants were not allowed to
communicate with each other during the entire experiment. They did not know with whom
they interacted among the other participants. After the experiment, each participant was paid
in privacy based on his or her individual earnings in the experiment plus a show-up fee. The
individual earnings were converted into Canadian dollars with a factor announced in the ex-
periment instructions. On average, participants earned 30 Canadian dollars, including the
show-up fee, for a session that lasted about 90 minutes.
5 Experimental results
In this section we evaluate, based on non-parametric data analysis, the five predictions made
in Section 3 above. Each pair of participants forming a two-player group represents an inde-
pendent observation. Unless mentioned otherwise, all non-parametric tests are two-sided. If
no significance level is given, we require significance at the 10-percent level. We denote the
Wilcoxon signed ranks test as Wilcoxon test and the Man-Whitney u-test as u-test.
Prediction 1: Participants do not choose the team remuneration mode when it is in their
egoistic self-interest to choose private remuneration.
In the VOLUNTARY SYM treatment, team remuneration is chosen by both players and thus
realized in 45 percent of all periods.3 This is in sharp contrast to the subgame-perfect equilib-
rium of the game with its specific paremeterization. Comparing the first set of 15 periods to
the final set of 15 periods, the relative frequency of team remuneration exhibits no tendency
to increase or decrease over time (Wilcoxon test).
3 In 34 percent of all periods both players choose private remuneration, while in 21 percent of all periods private
remuneration is realized due to one player choosing team remuneration but the other player choosing private
remuneration.
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