Explain why some people are able to hear ultrasonic sounds that are inaudible to most people.

The resonance frequency of the ear

The concept of ear resonance frequency is key here. Human ears are programmed to pick up sounds between 20 Hz and 20 kHz. The resonance frequency is the sweet spot where our ear is ultra sensitive. It varies from person to person but usually hovers around 2-5 kHz for most of us. Some people can detect ultrasounds beyond 20 kHz because their ears resonate at higher frequencies. This can be due to the shape and behavior of the inner ear, such as stiffer cochleae or more responsive auditory cells.

Individual sensitivity

Some people have a higher individual sensitivity to ultrasounds. This means their ears are more reactive than those of others. This can come from the internal structure of the ear. The hair cells, which detect sounds, might be more numerous or better aligned. It's somewhat like having super sensitive sensors. Sometimes, it's just a matter of genetic luck. Some people are born with this ability, just like others are born with better eyesight. It's rare, but it exists.

Sure, here is the translation of "Effets de l'âge" from French to English: "Effects of age"

As we age, our hearing abilities decline. This is a normal phenomenon. The cells in our inner ear, called hair cells, wear out. They process sounds, especially ultrasound. The older we get, the less efficiently these cells function. The brain also has more difficulty processing high-frequency sounds. Young ears capture these high-pitched noises better. Older individuals gradually lose this ability. Ultrasound then becomes just an invisible memory to their ears.

Genetic competence

Some people can hear ultrasounds due to genetic variations. These variations influence the hair cells in the ear. These cells are responsible for the conversion of sound vibrations into electrical signals for the brain. The variations can make these cells more sensitive to high frequencies. It's a bit like having a built-in boost to pick up sounds that most people cannot hear. Some studies show that these variations are often inherited from parents. So, if someone in your family can hear ultrasounds, there's a chance you might be able to as well. Fascinating, isn't it?

Environmental Exhibition

Some people have a better perception of ultrasounds due to their daily environment. People regularly exposed to high-pitched sounds, such as musicians or sound technicians, develop a more refined ear. Also, those who live in very noisy cities or near industrial areas may have an increased sensitivity to certain frequencies. The brain adapts and becomes more efficient at detecting these sounds. Studies show that children growing up in rural environments often have better auditory sensitivity than those in urban settings; their exposure to more natural sounds helps them develop this skill.

Practice and auditory training

Here is the translated text from French to English:

For some, understanding ultrasounds becomes possible thanks to years of practice and auditory training. Just as an athlete trains for a competition, the ear can be finely tuned to pick up sounds beyond the normal spectrum. Professionals such as musicians, sound technicians, or even wave hunters dedicate hours to exercising and refining their hearing. Through intensive training, their ears develop abilities that may seem almost supernatural. Certain specific exercises, like listening to high-frequency sounds at low volumes, can enhance this skill. These practices not only transform auditory perception, but they also literally modify the sensitivity of the inner ear.