From 1825-1985, the span of the skull has increased by about a third of an inch. The size amounts to about a tennis ball worth of additional volume. This doesn't necessarily translate to greater intelligence.
Anthropologist Richard Jantz, shared the findings at a meeting of the American Association for Physical Anthropology. Scientists aren't certain why this might be happening, but have suggested some possible explanations: increased c-sections, vaccinations, or changes in diet or exercise.
