Research taking place at two major United States universities suggests that humans have a better sense of smell than previously realized and that training olfactory senses can turn many people into experts on specific aromas. It may explain why some people are able to detect subtle differences between wines, beers and spirits, and are able to spot flaws more readily.
Researchers at Northwestern University's Feinberg School of Medicine and the University of California-Berkeley have been engaged in separate research studies looking at how the brain tells the difference between certain smells, how we learn the differences between thousands of odors during childhood and if humans can detect small amounts of lingering odors in the same way that bloodhounds do in tracking a scent.
At Northwestern study subjects were asked to smell either a mint or floral odor for 3.5 minutes. After the exposure the researchers found the study participants were much better able to detect differences between either a range of various minty or floral odors, depending on which single smell they had been exposed to in the category. The new experts in mint or floral smells retained this ability for at least 24 hours.
The Northwestern researchers used functional MRI techniques measuring subject brain activity to find that prolonged odor exposure generated increased brain activity in the orbitofrontal cortex and created an enhanced response to the smells. The study, which will be published in the journal Neuron, suggests that the information stored in that area of the brain is constantly updated during our lives. The more activity in this part of the brain, the better the sense of smell.
In the Berkeley study, undergraduate students were placed in a field wearing blindfolds and headphones to muffle sounds. They were then asked to play human bloodhounds and crawl along the ground to follow a trail of chocolate perfume. The students were able to accurately track the faint odor. The researchers also found that humans smell in stereo. When the researchers blocked the participants ability to smell independently through each nostril, the ability to track odors dropped significantly.
The Berkeley study, which will be published in the journal Nature Neuroscience, was partially funded by the U.S. Army. The hope is that an electronic nose can be created to help located hidden explosives and land mines.