Read the full transcript of marine biologist and composer Dr. Heather Spence’s talk titled “How To Listen Like A Fish”, at TEDxGeorgeMasonU, June 20, 2025.
Listen to the audio version here:
The Hidden World Around Us
Dr. Heather Spence: Do you ever stop to think about the things you’re not noticing? What if forces we can’t see affect the things we do? I’m going to share with you some tricks to tune in to your surroundings. I learned them from the ocean.
In the ocean, visibility is often poor, but sound travels fast and far. Marine ecosystems rely on sound. And yet, Jacques Cousteau, who pioneered the use of scuba diving for humans to be able to breathe underwater, referred to the ocean as “the silent world.”
Why at a time when humans were getting closer to the ocean than ever before, were we missing this central feature? Was it because we didn’t know anything about the underwater sounds? No. Even back in the fourth century, Aristotle described the sounds that fish make.
So how could we think about the ocean as silent? Well, one reason is that scuba divers produce a lot of noisy bubbles. Even if you aren’t a diver, this may sound familiar because actually the sound of scuba diving is sometimes used in movies to evoke a sense of being in the ocean. But this is not the sound of the ocean. It’s the sound of a human being trying to breathe underwater. And it covers up the real sounds of the ocean.
The Ocean’s Symphony
Here are sounds of a coral reef. That was a fish grunting. You’re also hearing shrimp crackling, lobsters scratching, water moving. The ocean is a world of sound.
And this resonates with me because in addition to being a marine biologist, I’m also a musician and composer. My training and interest in music led me to wonder, what can we learn about the ocean by listening to it? And I’ve spent the last 20 years exploring that question.
Here’s what I do. I put a microphone on the seafloor and I leave it there recording for months eavesdropping on fish. And I get a lot of information. It’s constantly recording day and night. It makes sense to study this underwater world of sound by listening to the sounds. Fish live in a world of sound.
Learning from Fish: Our World of Sound
But what does this mean for us humans? We say that humans live on land. That’s kind of a funny expression when you think about it. Yes, we walk on the land. But actually we live in air. We’re surrounded by air. Our sensory organs function optimally in air. So sounds travel through the air. We also live in a world of sound. And I realized that we humans are limiting ourselves by not paying attention to our world of sound.
Now let’s consider the human visual field versus auditory field. The space we can see versus the space we can hear. Contrary to what my daughter thinks, I do not have eyes on the back of my head. I can see in front of me. I have some peripheral vision. But if I want to see what’s behind me, I have to turn my head.
Guess what? Fish don’t have necks. Yeah. Fish have their head connected straight to their body. They’re saying, “we don’t need necks because we live in a world of sound.”
So what if we want to know what’s going on behind us without turning to look? Let’s be fish. Let’s listen. We can use our ears. We can also feel the vibrations of sound with our skin, our bodies. We can detect sounds from literally all around us. We can even detect sounds in the dark. We can detect sounds from in front of us that are hidden from view because sounds bounce and move around objects. Just think about echoes.
The Power of Sound
When you sleep, your eyes are closed, but your ears are open. You can feel vibration. Our ability to receive sounds is so important, we keep it turned on even when we’re sleeping.
Sounds convey information. Some sounds are powerful enough to attract our attention, and some are more subtle. You have to be paying attention in order to notice them. They might be providing information about danger, time of day, cues to do something, or information about food.
Now maybe you think, what if I don’t recognize certain sounds? That is something that can be practiced and honed, and some will remain a mystery. Certainly many are underwater, at least for us humans. But you already have an inventory of sounds. There are sounds that you can definitely recognize, and you might be able to get pretty specific about it.
Sounds also evoke emotions. So when you think about music, you might choose a song to suit your mood, or maybe a song to change your mood. But sounds that aren’t part of music also impact us emotionally. Think about how you feel when you hear ocean waves, or fingernails on a chalkboard, or the crackling of fire. Different people are going to have different reactions to sounds based on their own sonic memories and associations. So get to know your own responses to different sounds.
How Sound Affects Us
So an interesting example of this is the Lombard effect. What happens is, in a noisy environment, we raise our voices, and maybe that seems obvious because we’re raising our voices in order to be heard, but it actually happens even if you’re not aware of it happening. And it’s kind of a problem in choirs, because everyone starts singing louder and louder and louder and louder without realizing it.
Some other examples of these kinds of effects are entrainment, where your body’s movements are matching the rhythm of a sound, or alarm fatigue in hospitals, where hospital workers stop noticing the bleeps and bloops of the monitors.
You respond to sounds even if you don’t realize it.