Fossil ear bones reveal shift in human hearing

摘要

Now hear this. A reconstruction of fossil ear bones has found that human hearing shifted towards picking up frequencies useful in speech very early in our evolution. Rolf Quam of Binghamton University in New York and his colleagues studied skulls and ear bones from Australopithecus africanus and Paranthropus robustus, which lived between 1 million and 3 million years ago, as well as those of modem humans and chimps. Using CT scans, they built 3D models of the ears of each species. Then they used chimp and human anatomical data to work out what frequencies these ears could pick up. Modern humans and chimps perform similarly below 3 kilohertz, but we have better hearing in the 3-5 kHz range. The early hominins had a similar range to chimpanzees, but shifted slightly towards that of modern humans, with better hearing around 3-4 kHz (Science Advances, doi.org/7w6).