  Humans and animals are able to generalize information from previous
experience so that they can behave appropriately in novel situations -- but
what neural mechanisms give rise to this amazing ability? This Generative
Adversarial Collaboration (GAC) started out with the aim of arbitrating between
two alternative accounts: (a) memories for past experiences are integrated in
the brain to allow for such generalization, versus (b) generalization is
computed on-the-fly using separately stored (unintegrated) memories. The
members of this GAC come from a range of academic backgrounds and across the
course of this collaboration we found that -- although we often use different
terminology and techniques, and although some of our specific papers may
provide evidence one way or the other -- in reality we are generally in
agreement that both of these accounts (as well as others) might be valid. We
believe that different mechanisms might be weighted according to specific
conditions or task factors, or even implemented in parallel in the brain. Here,
we introduce some of the main mechanisms that have been proposed to underlie
generalization, we discuss the issues currently hindering better synthesis of
generalization research, and we propose the way forward in tackling some of
these issues. Finally, we introduce some of our own research questions that
have arisen over the course of this GAC, that we think would benefit from
future collaborative efforts.
