The Separation of Humans from Chimpanzees Accompanied by Changes in Auditory Quality

Scientists are trying to understand the hearing capabilities of early humans based on two-million-year-old fossils of three slender middle ear bones. They aim to determine whether these early humans heard sounds more like modern humans or like chimpanzees. This research examines two known species of early humans in South Africa (Australopithecus africanus and Paranthropus) and shows that their ears could hear sounds better than chimpanzees or contemporary hominins in the African plains. Both species studied had a combination of human-like and ape-like anatomical features and lived in vast plains with scattered bushes and trees, an environment different from the forest habitats of previously found human specimens. In both species, auditory sensitivity was slightly better than that of chimpanzees or humans of that era. Rolf Quam, a professor at New York University, told Reuters that this range of hearing includes some vowel sounds and certain consonant syllables: 'This model of auditory capability seems particularly useful for life in the African plains. In open spaces, sound waves do not travel as far as in a forest environment. Therefore, communication with sounds that have shorter wavelengths would have been more effective.' Quam states that the lineage of humans and chimpanzees separated between five to seven million years ago, and it appears that the auditory capabilities of our ancestors changed depending on their living environment to better communicate with their surroundings. To study the hearing ability of these two early human species, researchers were able to reconstruct a computer model of the ear using several found middle ear fossils. One of the differences between modern humans, who evolved about two hundred thousand years ago, and early human species is in auditory power. We are capable of hearing sounds with frequencies between one and six kilohertz. This range includes many sounds that emerged with the speaking of humans and the formation of various languages.