Evolution of cognitive function via redeployment of brain areas

Figure 3: The cortex represented as an adjacency graph, showing the Brodmann areas as nodes, with lines

between adjacent areas. The darkened nodes are those activated by an attention task reported by Corbetta
(1993). That task activated left Brodmann areas 7, 8 and 24, and right Brodmann areas 7 and 32; average
minimum graph distance is 4.0, close to the average for all tasks.

With this basic data in front of us, we can look at correlations between these values and
phylogenetic age. As noted above, if the evolution of cognition proceeded via the
extensive re-use of existing components, then evolutionarily more recent cognitive
functions should activate more, and more widely scattered brain areas. Comparing
language tasks with perception tasks and attention tasks gives the predicted result. For
the mean number of areas activated, language is greater than perception by 2.93 (2-
sample Student’s-t test, double-sided p = 0.0165) and greater than attention by 2.55 (p =

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