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Department of Anthropology

Academic Staff

Publication details for Prof Robert A. Barton

Barton, R.A. & Venditti, C. (2013). Human frontal lobes are not relatively large. Proceedings of the National Academy of Sciences of the United States of America 110(22): 9001–9006.

Author(s) from Durham

Abstract

One of the most pervasive assumptions about human brain evolution
is that it involved relative enlargement of the frontal lobes.We
show that this assumption is without foundation. Analysis of five
independent data sets using correctly scaled measures and phylogenetic
methods reveals that the size of human frontal lobes, and of
specific frontal regions, is as expected relative to the size of other
brain structures. Recent claims for relative enlargement of human
frontalwhite matter volume, and for relative enlargement shared by
all great apes, seem to be mistaken. Furthermore, using a recently
developed method for detecting shifts in evolutionary rates, we find
that the rate of change in relative frontal cortex volume along the
phylogenetic branch leading to humans was unremarkable and that
other branches showed significantly faster rates of change. Although
absolute and proportional frontal region size increased
rapidly in humans, this change was tightly correlated with corresponding
size increases in other areas andwhole brain size, and with
decreases in frontal neuron densities. The search for the neural basis
of human cognitive uniqueness should therefore focus less on the
frontal lobes in isolation and more on distributed neural networks.