We explore how your brain creates smell memories

Jonas Olofsson is a professor of psychology at Stockholm University. Together with his research group, he seeks to understand how the sense of smell affects our experiences, memory, and emotions. He is also an author, writing about his research in popular books and magasines.

Why is the sense of smell such a hot topic right now? 

“The pandemic made many people aware of what it means to lose their sense of smell or experience a distorted sense of smell. There were those who got up and smelled ground coffee every morning to see whether they could smell or had to isolate themselves. This has led many to think about smells differently now.”

What constitutes a smell? 

“Each odour is unique. The aroma of coffee, for instance, contains around 50 different molecules. The brain receives reactions in the nervous system from each of these molecules and assembles them into a pattern we interpret as the smell of coffee.”

How does this process work? 

“In the roof of the nasal cavity, there is a mucous membrane containing two olfactory epithelia with nerve fibres that extend into the mucosa. When we breathe in or out, scent molecules enter and make contact with these fibres. But smelling is just as much about psychology. Research shows that our sense of smell is more of a thinking process than we previously thought. It is learned. Our brain recognises that certain molecules belong together and interprets them within a given context. But how exactly does this work? That is what we are investigating.”

We have the largest psychology department in Sweden, with expertise spanning nearly every area of psychology. There is something for everyone interested in the subject.

Are there good and bad smells? 

“Yes, because that is how our brains are wired, but exactly which smell we like or dislike is subjective. It's not set in stone. Take, for example, the smell of durian, a fruit that many find overwhelmingly pungent. Yet, for some, it evokes feelings of happiness. The meaning of a scent depends on the context in which it is perceived. Depending on the sensory input the brain receives from other senses, a smell can take on different meanings.”

Is the sense of smell more dependent on other senses than, for instance, vision? 

“Yes, I think so, and in my research I have done my best to answer this question.”

How do you research the sense of smell?

“Many researchers in the natural sciences base their conclusions on studies of other animals, such as fruit flies or mosquitoes, to infer how the human sense of smell works. This perspective often assumes that smell molecules themselves determine reactions. My hypothesis, however, is that our psychology determines how we perceive scents. 

As cognitive scientists, we draw insights from experimental psychology, neuroscience, linguistics, and philosophy, using observations of behaviour in experimental settings to understand mental processes.”

What does teaching mean to you? 

“I find it incredibly rewarding for me as a researcher. I learn a lot myself. When you have to explain things, you realise what you know and and how well you know it. It's a good way to get better.

Interacting with students helps you grow. They ask smart questions and expect you to be able to provide meaningful answers. This sharpens your knowledge and sparks creativity. It is also simply great to be around young adults who are eager to learn and interested in their field of study–it is rewarding.”

Why study psychology at Stockholm University? 

“We are the largest psychology department in Sweden, with expertise spanning nearly every area of psychology. There is something for everyone interested in the subject.”

What is your research group currently working on? 

“Our primary focus is on how smells are connected to memory. Right now, we are investigating words used for scents in different languages. Why is it so difficult to describe a smell? And how does the brain keep track of different scents across various memory systems?”

What do the Gösta Ekman Laboratories mean for your research? 

“They are an important meeting place for researchers studying perception linked to our senses, such as vision, hearing, smell, taste, and touch. In the high-tech sensory labs, you can study everything from eye movements, to three-dimensional sound environments and scents in custom-developed VR environments.”

What is next?

“One question currently intriguing me is whether people in different parts of the world experience smells in the same way. Another question is the relationship between lower and higher sensory processes in the brain. Does memory process scent in the same way as other sensory inputs, or does the brain have separate pathways for different senses?”

Jonas Olofsson’s favourite smells

• His son, coffee in the morning and the sea
• Another one is the scent of old books. It may not be objectively pleasant, but when I find an early edition of a book I’ve been looking for in an antiquarian bookshop, and stick my nose in it, it brings a sense of joy.