Research groups such as Kyoto University have summarized the research results that humans have become able to manipulate language in the process of evolution because the structure of the throat is simpler than that of monkeys and they can produce sounds stably. .
It is attracting attention as a result that will lead to the elucidation of the process by which humans acquired language.
A research group led by Associate Professor Tsuyoshi Nishimura at the Research Center for Human Behavioral Evolution at Kyoto University focused on the "vocal cords" in the throat to elucidate the process by which humans acquired language. compared with the specimen.
As a result, they discovered that all monkeys have a tissue called "vocal membrane" near the vocal cords, which humans do not have.
Furthermore, as a result of experiments to observe the movement of the throat in chimpanzees, etc., it was found that while the vocal cord membrane amplifies the sound emitted from the vocal cords and plays a role in making the voice louder, it also interacts with the vocal cords, resulting in the loss of voice. It turned out that it was difficult to keep the size and height constant.
Humans who do not have a vocal cord membrane vibrate their vocal cords to make sounds, and use their lips and tongue to adjust the pitch. It is concluded that this led to the acquisition of language.
Associate Professor Nishimura says, "In the future, I would like to clarify the mechanism by which language is acquired, such as how the brain controls the vocal cords."
Specimens and data accumulated over 50 years enable research
What made this research possible was the specimens and data accumulated over more than 50 years in domestic zoos.
The Monkey Center, a zoo in Inuyama City, Aichi Prefecture, where various primates such as Japanese macaques and chimpanzees are kept, was opened in 1956 through the efforts of Kyoto University researchers.
In addition to serving as a base for research on primates in Japan, the attached museum has stored related specimens and data.
For this research, ▽ 43 species of monkey throat specimens collected over more than 50 years and ▽ data obtained by observing the vibrating vocal cords of chimpanzees were used.
Associate Professor Tsuyoshi Nishimura of the Research Center for Human Behavioral Evolution, Kyoto University, who is part of the research group, said, "This research was made possible largely by the materials and data that the Center has accumulated over many years. There is no other place where this kind of research can be done."