Jeremy Genovese, an associate professor of human development and educational psychology at Cleveland State University, insists that the link between head size and IQ may be minimal but it does exist.
"The correlations between head size and IQ are quite modest, and you cannot determine someone's intelligence with a tape measure. However, the correlation is real and might have some clinical significance, such as predicting susceptibility to dementia," Discovery News quoted him as saying.
He, however, said that though "larger bodies do require larger brains to support larger nervous systems," the notable difference in body size between men and women appeared to have "no relationship to intelligence."
For the study, Genovese obtained copies anthropological and sociological records on roughly 12 percent of on roughly 12 percent of American prison inmates in 1939 study, collected by Harvard anthropologist Earnest Albert Hooten.
Since IQ tests had already been performed on the 676 male inmates at the Concord Reformatory in Massachusetts, Hooten had documented their head circumference, head length, head height and even head shape.
Genovese said that he used statistical computer software to find patterns hidden from Hooten, considering the more limited methods of his day.
He revealed that he did not find any evidence showing an association between a rounder head and greater intelligence, as many scientists often claim. However, the analysis enabled him to confirm Hooten's suggestion that there exists a connection between head size and intelligence.
Genovese speculated that a fitness factor could be influencing the results because size of the body parts is one indicator of overall physical fitness. He said that a fit person could be more likely to have both a larger head and smarter brain.
He, however, still said that he was not sure whether fitness, rather than head size, was the direct cause of intelligence. "It is quite possible that greater body size, head size and IQs are, in this sample, proxies for some other variables, such as nutrition or socio-economic status," he said.
Based on his findings, Genovese said that it could be possible that the intelligence of Neanderthals had been underestimated to date because they had big heads.
"I rather think that the Neanderthals get a bad rap," he said.
The study has been accepted for publication in the journal Personality and Individual Differences.