UC Berkeley research shows that smell plays part in human navigation

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People can map a landscape based on just its various smells, according to a team of UC Berkeley researchers.

The researchers — supervised by Lucia Jacobs, a professor in UC Berkeley’s psychology department — discovered that people can identify and locate an arbitrary space based on the combination of smells in that location relative to the surrounding area. The study, published June 17 in the journal PLOS ONE, is the first of its kind and may change how scientists think about humans’ use of the sense of smell.

Previously, it had been assumed that olfaction, or the sense of smell, was used as a means of finding and identifying specific objects rather than as a means of mapping and navigating space, according to Jacobs, the lead author of the study. Whereas research has demonstrated the ability of many animals — humans included — to track objects based on smell, there was no evidence of the ability to map a location based on the mixture of smells in the area.

“You may not realize it,” Jacobs said, “but you’re identifying each space by the smells of the space, and that may be a big part of how you map that space.”

For the study, the researchers blindfolded and earplugged 45 undergraduates, even giving them headphones to definitively cut out their hearing and leave them only with a sense of smell. They used two smell-soaked sponges placed on the edges of the test room to create an “odor landscape.” The students were given a minute to familiarize themselves with the smell of a specific location and then had to attempt to find their way back after being disoriented.

While they were free to use all of their senses to find the old location, the students knew only its smell.

Participants were able to more accurately return to the target location when using smell compared with participants in the control setting, where sight, smell and hearing were all blocked, according to Jennifer Arter, a research assistant at UC Berkeley’s Helen Wills Neuroscience Institute who worked on the study.

“The human olfactory system is a very underestimated system,” Jacobs said. “It’s very understudied — that’s why we can do this simple study and have it be the first of its kind.”

This research opens a new realm for future studies on the use of olfaction in navigation among different species and settings, she said.

Arter said the next steps for research on this topic would be to flesh out the effects of olfaction on previous studies of mental mapping and navigation, which did not control for the odors present during those studies. Additionally, further research is needed to examine the brain’s olfactory bulb, which may have functions different from what was previously thought, she said.

Contact Ethan Walker at [email protected] and follow him on Twitter @ethannwalker.