Evolution of cognitive function via redeployment of brain areas

capacities, without disrupting their participation in existing programs. If cognitive
functions evolved in this way, then we should be able to make some specific empirical
predictions regarding the resulting functional topography of the brain; here I discuss
three.

First and most generally, we should expect a typical brain region to support numerous
cognitive functions in diverse task categories. If this were not the case, if a typical brain
region in fact served a very limited set of cognitive functions, then this would suggest
instead that the brain evolved by generating new, dedicated regions for each new
purpose.

Second, there should be a correlation between the phylogenetic age of a brain area and
the frequency with which it is deployed in various cognitive functions. The longer an
area has been around the more likely it will have proved useful to some evolving
cognitive capacity, and be incorporated into the functional network of brain regions
supporting the new task. Naturally this will not be true for every brain region, since a
given area may have evolved to serve a very particular purpose of little use in later
developments. But it should be generally the case that the older an area is, the more
cognitive functions it supports.

Third and finally, there should be a correlation between the phylogenetic age of a
cognitive function and its degree of localization. That is, more recent functions should
generally use more, and more widely scattered brain areas than evolutionarily older

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