  Imitation is an important learning heuristic in animal and human societies.
Previous explorations report that the fate of individuals with cooperative
strategies is sensitive to the protocol of imitation, leading to a conundrum
about how different styles of imitation quantitatively impact the evolution of
cooperation. Here, we take a different perspective on the personal and external
social information required by imitation. We develop a general model of
imitation dynamics with incomplete information in networked systems, which
unifies classical update rules including the death-birth and
pairwise-comparison rule on complex networks. Under pairwise interactions, we
find that collective cooperation is most promoted if individuals neglect
personal information. If personal information is considered, cooperators evolve
more readily with more external information. Intriguingly, when interactions
take place in groups on networks with low degrees of clustering, using more
personal and less external information better facilitates cooperation. Our
unifying perspective uncovers intuition by examining the rate and range of
competition induced by different information situations.
