A new analysis by anthropologists of the 1.8-million-year-old skullcap of a Homo erectus child, discovered on the Indonesian island of Java in 1936, indicates that the youngster’s brain grew relatively quickly, much as the brains of modern chimpanzees do.
The prehistoric child died at around age 1 but already possessed a brain case that was at least three-quarters the size of that for an average adult H. erectus, report Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and his colleagues. In contrast, a modern person’s brain reaches only about one-half of its adult size by age 1.
This disparity in the timing of brain growth “makes it unlikely that early Homo had cognitive skills comparable to those of modern humans,” such as speaking grammatically complex languages, the scientists conclude in the Sept. 16 Nature.
Hublin’s group used computed tomography scans to assess signs of bone maturation in the fossil, known as the Mojokerto child, and in modern skulls from 159 children and 201 young chimpanzees.
Prior analyses of the Mojokerto child had assigned it an age at death ranging from 1.5 to 8 years, solely on the basis of comparisons to modern human skulls.