  The achievement of common goals through voluntary efforts of members of a
group can be challenged by the high temptation of individual defection. Here,
two-person one-goal assurance games are generalized to N-person, M-goal
achievement games in which group members can have different motivations with
respect to the achievement of the different goals. The theoretical performance
of groups faced with the challenge of multiple simultaneous goals is analyzed
mathematically and computationally. For two-goal scenarios one finds that
"polarized" as well as "biased" groups perform well in the presence of
defectors. A special case, called individual purpose games (N-person, N-goal
achievements games where there is a one-to-one mapping between actors and goals
for which they have a high achievement motivation) is analyzed in more detail
in form of the "importance of being different theorem". It is shown that in
some individual purpose games, groups of size N can successfully accomplish N
goals, such that each group member is highly motivated towards the achievement
of one unique goal. The game-theoretic results suggest that multiple goals as
well as differences in motivations can, in some cases, correspond to highly
effective groups.
