  The spontaneous organization of collective activities in animal groups and
societies has attracted a considerable amount of attention over the last
decade. This kind of coordination often permits group-living species to achieve
collective tasks that are far beyond single individuals capabilities. In
particular, a key benefit lies in the integration of partial knowledge of the
environment at the collective level. In this contribution we discuss various
self-organization phenomena in animal swarms and human crowds from the point of
view of information exchange among individuals. In particular, we provide a
general description of collective dynamics across species and introduce a
classification of these dynamics not only with respect to the way information
is transferred among individuals, but also with regard to the knowledge
processing at the collective level. Finally, we highlight the fact that the
individuals' ability to learn from past experiences can have a feedback effect
on the collective dynamics, as experienced with the development of behavioral
conventions in pedestrian crowds.
