Figure 2: A plot of the number of tasks (out of 135) that activated each Brodmann area vs. the Y
coordinate of the area (calculated in Talairach (Talairach and Tornaux, 1988) space using the Brede
(Nielsen, 2003) database). The data shows a linear correlation, R = -0.4121, p <= 0.00244 (t = -3.198, DF =
50).
Discussion
Together, these data suggest a picture of the evolution of cognition where redeployment
plays a significant role. As predicted, we see correlations between phylogenetic age of
brain areas and the frequency of their participation in cognitive function, and between the
age of cognitive functions and their degree of localization. We also saw that the typical
brain area is a diverse instrument, supporting cognitive tasks in multiple task categories.
The massive redeployment hypothesis thus appears to be both empirically supported, and
consistent with the evidence for evolution by exaptation in both psychology and
neuroanatomy.
14