Sound and Brain
Oto-kun
Is it true that Japanese people and Westerners process sounds in different areas of the brain when they enter through the ears?
father
The research paper by Dr. Kakuta, studied over 30 years ago, is the starting point, but it became widely known through a book titled 'The Japanese Brain.'
Oto-kun
What differences are there?
father
First, you probably know that the brain has a left and a right hemisphere? There is a diagram (Figure 1, Reference 1) that shows the differences in brain activity between Japanese and Western people in response to various sounds, so let me explain that. The left brain is referred to as the language brain, while the right brain is known as the music brain or artistic brain, with the left being responsible for rational cognition and the right for emotional cognition. However, it seems that in Japanese people, rational and emotional cognition are mixed in the left brain.
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Figure 1
Oto-kun
Looking at this figure, it seems that Japanese people listen to various sounds with their left brain compared to Westerners.
father
That's right. A distinctive aspect is that vowels are processed in the left hemisphere of the brain. Originally, Dr. Kakuta's experiment was focused on the theme of whether language and non-language are predominantly processed in the left or right hemisphere. The test sounds used were a pure tone at 1 kHz for non-verbal sounds, and for verbal sounds, the sustained vowel 'ah' was used to represent human speech.
Oto-kun
Did you play that test sound to people from various countries to investigate which part of their brain they were using to listen to it?
father
That's right. To identify the areas of brain activity, nowadays we use fMRI (functional magnetic resonance imaging), which measures changes in blood flow in the brain. However, at that time, experiments were conducted using analog devices to measure the switching mechanisms of the brainstem system to determine which side of the brain processes speech. There were researchers who questioned the reliability of these results, but further experiments were conducted by other researchers using EEG and MEG (magnetoencephalography).
Oto-kun
Was the result the same as Dr. Tsunoda's?
father
In response to vowel stimuli, it was found that Japanese people activated their left brain while Americans activated their right brain, which corroborated Dr. Tsunoda's findings. (Reference 2) Additionally, sounds from crickets and other insects showed the same tendency.
Oto-kun
In this figure (Figure 1), the term "Hogakki" refers to Japanese instruments, right? It's interesting that Japanese people hear the sound of Hogakki with their left brain while they hear the sound of Western instruments with their right brain. The sound of the shamisen that was analyzed the other day is also heard by Japanese people with their left brain, but Westerners hear it with their right brain, right?
father
That's right. That's also a distinctive difference. Japanese people perceive sounds with vowel-like structures, such as traditional Japanese instruments and natural sounds, all in the left hemisphere of the language brain. The sound of a temple bell, "Gooon," might also be heard as having a vowel-like quality in its resonance.
Oto-kun
What about people from other Asian countries and Japanese people who were raised abroad?
father
The uniqueness of the Japanese brain's response to this sound is said to be attributed to the Japanese language for now. Therefore, Koreans and Chinese also show the same tendencies as Westerners, and even Japanese people who do not have Japanese as their mother tongue exhibit brain lateralization patterns similar to those of Westerners.
Oto-kun
Japanese people hear the sounds of insects with the left hemisphere of their language brain.
father
Japanese people have a unique way of listening to the sounds of insects. There is an interesting story about insect sounds that I will summarize and tell you next time.
Oto-kun
If Japanese people have a different sense of sound compared to people from other countries, could that lead to any problems?
father
I can't say for sure that the perception is different, but especially regarding natural sounds like the sounds of insects or rain, there is a significant difference from people in other countries in that we don't simply treat these sounds as physical phenomena; instead, we feel the seasons, connect them to human emotions, and find meaning in them. This is influenced by Japan's culture of incorporating nature rather than confronting it, and perhaps Japanese people could be more conscious of this.