John Hopton for redOrbit.com – @Johnfinitum
Our human ancestors relied heavily on smell for hunting and even mating, and early sailors told yarns about using smell for navigation.
Humans can navigate purely using remembered smells, a new study from the University of California, Berkeley has found. The discovery is evidence that we have a kind of olfactory GPS system and our sense of smell is more powerful than previously thought.
“What we’ve found is that we humans have the capability to orient ourselves along highways of odors and crisscross landscapes using only our sense of smell,” said study lead author Lucia Jacobs, a UC Berkeley psychology professor, quoted in a EurekAlert report.
“Olfaction is like this background fabric to our world that we might not be conscious of, but we are using it to stay oriented,” she added. “We may not see a eucalyptus grove as we pass it at night, but our brain is encoding the smells and creating a map.”
Plenty of animals use scent for navigation, of course. Search and rescue dogs are one obvious example, and rats and pigeons, for instance, orient themselves using odor maps, or “smellscapes.” But this is the first in-depth study of the process in humans, who generally rely on visual aids for orientation, and the presence of such an advanced smell-based positioning system was surprising to researchers.
Testing the system
The researchers gave orientation and navigation tasks to 24 young adults, whose hearing, sight, or smell was blocked. They were tested in a 25-by-20-foot room using 32 containers with sponges placed around the edges. The sponges were used in pairs and infused with essential oils such as clove, sweet birch, or anise.
To test how much smell played a role in navigation, the participants wore earplugs, blindfolds and headphones and were led into the room one by one before being walked in circles to disorient them. They inhaled a combination of two fragrances for one minute, at a certain point on the grid. They were disoriented once more, and then asked to sniff their way back to the point at which they had smelled the two fragrances.
Having tested the blockage of different senses, overall smell was judged to be an effective means of navigation. Furthermore, the participants were not only following one scent, but using information from both scents to guide themselves toward a location on the odor grid.
Olfactory bulbs, which are positioned between the nasal cavity and the brain’s frontal lobe, have a strong neural link to the brain’s hippocampus, which creates spatial maps of our environment. However, Jacobs said, “We never thought humans could have a good enough sense of smell for this.” Now, though, she says the results are “as obvious as the nose on my face.”
This summer, Jacobs will explore the mechanism further as a scientist on the team of the National Science Foundation’s “Cracking the Olfactory Code” Ideas Lab.
—–
Follow redOrbit on Twitter, Facebook, Google+, Instagram and Pinterest.
Comments