  When people collaborate, they expect more in return than a simple sum of
their efforts. This observation is at the heart of the so-called public goods
game, where the participants' contributions are multiplied by an $r$ synergy
factor before they are distributed among group members. However, a larger group
could be more effective, which can be described by a larger synergy factor. To
elaborate on the possible consequences, in this study, we introduce a model
where the population has different sizes of groups, and the applied synergy
factor depends on the size of the group. We examine different options when the
increment of $r$ is linear, slow, or sudden, but in all cases, the cooperation
level is higher than that in a population where the homogeneous $r$ factor is
used. In the latter case, smaller groups perform better; however, this behavior
is reversed when synergy increases for larger groups. Hence, the entire
community benefits because larger groups are rewarded better. Notably, a
similar qualitative behavior can be observed for other heterogeneous
topologies, including scale-free interaction graphs.
