Brain size and animal learning and cognition pearce pdf varies considerably between different species. 49 years and of mainly European descent, found an average brain volume of 1273.
The adult human brain weighs on average about 1. The average weight is about 1370 g in men and about 1200 g in women. Brain size has increased considerably over the course of humans’ recent evolutionary history. Some studies suggest that the average brain size has been decreasing over the past 28,000 years.
Others suggest that the cranial capacity for males is unchanged, but that the cranial capacity of females has increased. Brain Size, Cranial Morphology, Climate, and Time Machines. The study found that human brain size varied with latitude of biogeographic ancestry. The relationship between latitude and cranial size is described in the study as an example of Bergmann’s principle that crania are more spherical in cold climates because mass increases relative to surface area to conserve core temperatures and behaves independently of “race”. Overall white matter volume does not appear to decline with age, although there is variation among brain regions. Average brain weight for males and females over lifespan.
Changes in brain weights during the span of human life. Males have been found to have, on average, greater cerebral, cerebellar, and cerebral cortical lobar volumes, except possibly left parietal. There was high variability among individuals, however. Significant dynamic changes in brain structure take place throughout adulthood, with substantial variation between individuals.
Men show a steeper decline in global gray matter volume, although in both sexes it varies by region with some areas exhibiting little or no age effect. Morton unconsciously misrepresented his data, and that when it was properly interpreted, it showed no significant racial differences in cranial capacity. This claim was criticized in a 2011 paper, which concluded that Morton did not manipulate his results, unconsciously or otherwise. This paper has, in turn, been criticized for making unwarranted conclusions as to whether Gould’s claims of bias were correct or not. His work in this area has been criticized for relying on flawed studies, for failing to consider explanations other than genetics for the observed differences, and for ignoring other studies with contradictory conclusions.