“The beautiful, mysterious science of how you hear” – Jim Hudspeth

By Sophie Teall

Snappy, educational, and only 15minutes long, “The beautiful, mysterious science of how you hear” is a TED talk from Dr Jim Hudspeth about the mechanics of hearing. It makes for a great watch anytime you have a few minutes to spare.

Hudspeth is a biophysicist and neuroscientist whose work focuses on the neural processes responsible for the human ability to hear. His talk begins with an explanation of how hair cells in the ear turn vibrations in the air into electrical signals and how the brain interprets them. While this alone is fascinating, things get even more so once he explains how the amplification system in the ears leads to them emitting their own unique tones. Such sounds are only detectable in an ultra-quiet room such as a sound chamber. This phenomenon certainly came as a surprise to me, yet Hudspeth talks through the process behind it in a simple and understandable manner. Finally, he discusses his own exciting research into how an understanding of hearing in other animals offers an insight into potential ways to prevent hearing deterioration in humans. Approximately 40% of people over 50 in the UK experience some form of hearing deterioration, often due to hair cell damage. Older people are already at risk of feeling isolated and with severe hearing deterioration may feel especially excluded if they have limited opportunity to learn or utilise a sign language within social interactions. While we are unable to replace hair cells once they become damaged or die, animals such as zebrafish continue to produce hair cells throughout their lives. It is a shame that Hudspeth only touches on this topic briefly and does not give more context about the intricacies of this area of research and our current level of knowledge. Hopefully, as research develops, more easily accessible content and media on the topic will become available.

This talk definitely has a large amount of information packed into a short time frame and it requires a high level of focus to absorb everything. However, the fascinating subject matter and engaging delivery makes it worth watching. 

Related TED talks of interest

If you have five more minutes to spare and some want additional context, the TED-Ed animation “The science of hearing” is worth a watch. It gives an overview of the auditory system, how vibrations travel through the ear, and how the brain processes the information. The information is presented very clearly, with a charming animation style that contributes to the engaging nature of the video.

Another interesting and short animation is “What’s that ringing in your ears?” which explores the phenomenon of tinnitus. Tinnitus refers to when a ringing or buzzing sound is heard despite the lack of an external source of the sound. You may have experienced this when leaving a club or concert after being exposed to loud music for several hours. While the sound emission discussed by Hudspeth is part of healthy ear function, tinnitus is a symptom of underlying conditions. Such conditions can lead to a signal being sent to the brain even though no sound waves triggered it. Despite being experienced by one in seven people worldwide, I personally was completely unaware of this phenomenon having a name, so I found this video particularly informative. This talk discusses why different forms of tinnitus occur and how they can be managed. It’s not as directly linked to Hudspeth’s talk as “The science of hearing”, but regardless it is definitely a fascinating watch regardless. 

In combination, these three talks offer an intriguing and concise insight into the inner workings of the ear. They certainly made me realise how little I know about the mechanics of hearing. 

Images

Caption: Scanning electron microscope images showing hair cells of a terrapin (right) and guinea pig (top left and bottom left). This shows the variation that hair cells can take in different animals. 

Credits: Photograph by Dr David Furness, distributed under CC BY-NC 4.0 license 

Caption: A diagram of the anatomy of a human ear. Hair cells are located in the cochlea (purple). Sound waves travel through the external auditory canal, causing the tympanic membrane (also known as the eardrum) to vibrate. This causes the three bones in the ear (the malleus, incus and the stapes, grey) to move. As the stapes vibrates it hits the cochlea and causes the fluid inside it to move, which results in the displacement of the hair cells. The hair cells consequently undergo a shift in electric charge distribution (known as depolarisation) and send signals to the brain. Sounds of different frequencies will stimulate hair cells at different locations in the cochlea. 

Credits: Diagram by Inductiveload, distributed under CC BY-SA 2.5

References

Fagelson, M. (2020) Whats that ringing in your ears? TED-Ed. Available at: https://www.ted.com/talks/marc_fagelson_what_s_that_ringing_in_your_ears (Accessed: December 8, 2020)

Hudspeth, J (2019) The beautiful, mysterious science of how you hear TED@NAS. Available at: https://www.ted.com/talks/jim_hudspeth_the_beautiful_mysterious_science_of_how_you_hear?language=en (Accessed: December 8, 2020)

Oliver, D. (2018) The science of hearing TED-Ed. Available at: https://www.ted.com/talks/douglas_l_oliver_the_science_of_hearing#t-2994 (Accessed: December 8, 2020).

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