  At the core of our uniquely human cognitive abilities is the capacity to see
things from different perspectives, or to place them in a new context. We
propose that this was made possible by two cognitive transitions. First, the
large brain of Homo erectus facilitated the onset of recursive recall: the
ability to string thoughts together into a stream of potentially abstract or
imaginative thought. This hypothesis is supported by a set of computational
models where an artificial society of agents evolved to generate more diverse
and valuable cultural outputs under conditions of recursive recall. We propose
that the capacity to see things in context arose much later, following the
appearance of anatomically modern humans. This second transition was brought on
by the onset of contextual focus: the capacity to shift between a minimally
contextual analytic mode of thought, and a highly contextual associative mode
of thought, conducive to combining concepts in new ways and 'breaking out of a
rut'. When contextual focus is implemented in an art-generating computer
program, the resulting artworks are seen as more creative and appealing. We
summarize how both transitions can be modeled using a theory of concepts which
highlights the manner in which different contexts can lead to modern humans
attributing very different meanings to the interpretation of one concept.
