Superpowers of Smell in Medical Diagnostics

How do human senses compare to those of animals? In what ways are they similar, how are they different, and how do they help us make sense of the world?

Ashley Ward is a Professor of Animal Behavior at the University of Sydney, Australia, and also the author of several books about animal behavior. His latest book is titled Where We Meet the World: The Story of the Senses.

Ashley and Greg discuss the complex labyrinth of sensory perceptions, illuminating how vision, taste, and smell can shape our understanding of the world. Ashley dissects the extraordinary ways animals and plants detect threats and communicate, the surprising power of smell in social insect communication, and interesting theories about the evolution of human behaviors like kissing and hand-shaking. They dive into animal behavior and group decision-making, including swarm intelligence and the dynamics of animal hierarchies in this fascinating exploration of animal behavior and sensory experiences.

*unSILOed Podcast is produced by University FM.*

Episode Quotes:

Can we train ourselves to smell fear and excitement?

08:53: So, there's a huge value to interacting directly with other people, and an awful lot of cues are provided that go beyond the visual and hearing when we communicate by language. As to whether we can smell fear and excitement, the evidence suggests that we do produce different chemicals when we are in an aroused emotional state, such as when we're terrified by something or when we're thrilled about something. And those kinds of subtle cues can be collected by other animals. Dogs are an obvious example. And we might think that we're simply not capable of this. Our sense of smell, let's say, is not sophisticated enough to pick it up, but it does vary enormously from person to person. And there are people who have such an exquisite sense of smell that they can start to pick up these cues.

Information is a vital currency to animals

47:20: Information is a vital currency for all animals, and by pooling that information in whichever way, they can develop much, much better strategies. That applies to humans: If we're trying to make excellent decisions, then the best way to do that is to take a broad view of the information that's out there. Now, there are two ways of getting that information. You can either go out there and collect it all yourself, which is incredibly time-consuming. Often, in many cases, totally impossible, or you can use social information, which is readily available and relatively cheap, and as long as you get enough of it, it's very accurate. This is what the animals are doing. 

Decoding scents

38:51: Our perception—our sensation of smell—is produced by a mosaic of different activations in the receptors. We have 400 different smell receptors, and each smell is a composite of different activation patterns. Receptor numbers 189, 157, and 14 might all be activated, giving you the smell of a tangerine. But if it's not 14, 15, then maybe that's a lemon or something. And that's the difficulty. There are so many different permutations of inputs that go into each smell. There's a very difficult matter to untangle that and find the exact right receptor activation pattern which corresponds to each different smell.

Taste complexity across species

43:30: The pattern is that the more carnivorous an animal is, the fewer the different kinds of tastes, the less sensitive its sense of taste is, and the more herbivorous an animal is, conversely. The more complex and sophisticated their sense of taste is. So cows have a much better sense of taste than we do. We sit somewhere in the middle. We have approximately the same complexity in our sense of taste as a pig does. We're more complex than cats and dogs. We're less complex than rabbits and cows.

Show Links:

Recommended Resources:

• Movie Theaters Smell Like People’s Feelings
• Hand Shaking and Smell
• Quorum Decision-Making in Foraging Fish Shoals
• Convoy battles of World War II
• Jack the Railway Baboon
• Assateague Island
• Bayesian inference
• Synesthesia

Guest Profile:

• Faculty Profile at The University of Sydney
• Ashley Ward's Website
• Ashley Ward on LinkedIn
• Ashley Ward on X

His Work:

• Where We Meet the World: The Story of the Senses
• The Social Lives of Animals
• Questions and Answers on Saltwater Aquarium Fishes: Understanding Behavior for Successful Fishkeeping
• Questions and Answers on Freshwater Aquarium Fishes: Everything You Need to Know to Successfully Raise Healthy
• Google Scholar Articles
• ResearchGate Articles