[The Science of Smell: Why Our Noses Perceive the World Differently]-[Tinkerclass (Week 4 Day 1): Getting Nosey About the Science of Smell]

Wow in the World · B1 · 2020-09-28

📋 Summary

The Science of Smell: Why Different Sniffs Get Different Whiffs

In this episode of Wow in the World, hosts Mindy and Guy Raz dive deep into the fascinating world of olfaction—our sense of smell. By exploring why individuals perceive scents differently, the episode unpacks the biological and genetic mechanisms that make our noses so uniquely capable of interpreting the world around us.

The Anatomy of Olfaction: How We Smell

To understand smell, we must first look at the human nose. Mindy explains that deep within our nasal passages, we possess approximately 400 different odor-detecting receptors. These microscopic sensors are responsible for catching tiny molecules from the air we breathe. Once these molecules land on the receptors, they trigger a neural message sent directly to the brain.

This process is highly sophisticated: the brain processes these signals to determine if a scent is familiar, pleasant, or a warning of danger—such as the smell of "freshly baked cookies" versus "harmful chemicals." Remarkably, the human olfactory system has the power to distinguish between at least one trillion different smells.

Genetic Variation and Perception

The core of the episode focuses on a scientific study conducted by geneticist Dr. Casey Trimmer and her team at the Monell Chemical Senses Center and Rockefeller University. The researchers sought to answer a fundamental question: Why do different people smell the same thing in drastically different ways?

By studying the DNA of participants, the researchers discovered that our sense of smell is heavily influenced by our genetic "instruction manual." They found that even the "teeniest, tiniest change" in a single olfactory receptor can completely alter how a person experiences a scent. This explains why some individuals might perceive the smell of androstenone (a chemical found in sweat) as pungent and gross, while others perceive it as vanilla-like, or cannot smell it at all. Similarly, it explains why some people find the scent of Lily of the Valley intense, while others remain oblivious to it.

Beyond Genetics: Memories and Context

While DNA plays a massive role in our perception, the hosts emphasize that it isn't the only factor. Our sense of smell is deeply intertwined with the part of the brain that holds memories. Because of this, our personal experiences and cultural associations significantly influence whether we find a smell pleasant or unpleasant.

For example, while a person’s genetic makeup might dictate the baseline intensity of a scent, the emotional context—such as a mother’s perfume signifying the "return of happiness"—shapes the subjective experience. Furthermore, the episode notes that our sense of smell is crucial for our overall health, as it plays a significant role in our dietary choices and how we interact with our environment.

Conclusion

The science of smell is a complex interaction between biology, genetics, and memory. By understanding that our receptors are unique to our own DNA, we gain a new appreciation for why the world smells different to everyone. As Mindy and Guy Raz conclude, while we may not be able to change our genes, our ability to explore and "wow" at the world through our senses remains one of the most remarkable features of being human.

🎯Key Sentences

That's it.

But for now, let's get on with the show.

And it's about time.

I might as well take you up on that offer.

I'll be down in a minute.

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📝Key Phrases

music to your ears

get on with the show

crash course

come to mind

take you up on that offer

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📖 Transcript

Grownups, Wondery Plus subscribers can listen to Wow in the World early and ad-free right now.

Join Wondery Plus in the Wondery app or Wondery Kids Plus on Apple Podcasts.

Hey, Wowzer fans, Mindy here.

And before we start the show, I gotta let you know that this November, with a special new episode featuring our friends at Circle Round and Terrestrials on Radiolab for Kids,

And don't miss when Elmo from Sesame Street stops by Wow in the World to make us all belly laugh on November 24th.

Oh, but that's not all, Reg.

Or study on the web version →