Brain frontal lobes not sole center of human intelligence

May 15, 2013

Credit: National Cancer Institute/Wikimedia Commons)

The frontal lobes in humans vs. other species are not — as previously thought — disproportionately enlarged relative to other areas of the brain, according to a study by Durham and Reading universities.

It concludes that the size of our frontal lobes — an area in the brain of mammals located at the front of each cerebral hemisphere — cannot solely account for humans’ superior cognitive abilities.

The study also suggest that supposedly more “primitive” areas, such as the cerebellum, were equally important in the expansion of the human brain. These areas may therefore play unexpectedly important roles in human cognition and its disorders, such as autism and dyslexia, say the researchers.

The scientists argue that many of our high-level abilities are carried out by more extensive brain networks linking many different areas of the brain. They suggest it may be the structure of these extended networks more than the size of any isolated brain region that is critical for cognitive functioning.

The Durham and Reading researchers, funded by The Leverhulme Trust, analyzed data sets from previous animal and human studies using phylogenetic (“evolutionary family tree”) methods, and found consistent results across all their data. They used a new method to look at the speed with which evolutionary change occurred, concluding that the frontal lobes did not evolve especially fast along the human lineage after it split from the chimpanzee lineage.