by Playfuls Staff |
18th December 2006
Dogs are well appreciated for their powerful smelling abilities but it seems human olfactory ability is wrongly deemed modest.
[more]
Researchers at the University of California at Berkeley conceived an experiment of their own which, though it looked funny at times, came up with some serious evidence. It appears people can follow a scent surprisingly well, having nothing else to rely on but their noses. Those who participated in the experiment were blindfolded and asked to wear sound-muffling headphones as well as thick gloves, kneepads and elbow pads.
A line of string was dipped in chocolate scent and then embedded in the grass, and the participants crawled away on all fours, trying to follow the track (this being the funny part of the research); they couldn’t see the string or feel it.
The serious part came when researchers found that their subjects were actually close on the trail – slowly but surely the people followed the scent and even took turns as the trail did.
The purpose of the experiment was to ascertain whether having two nostrils spaced slightly apart helps track a scent, just as having two ears enables the brain to locate the source of a sound.
The reason human beings were involved in the research instead of dogs, was that the latter cannot report their experience and are also reticent to having things placed in their nostrils. It seems psychology department undergraduates were much more compliant. As it turned out, when their ability to smell independently with each nostril was blocked, the students' scent-tracking accuracy dropped dramatically.
Another surprise was that the participants spontaneously mimicked some of the behavior that tracking dogs manifest, such as sniffing faster and zigzagging. A theory for the zigzagging is that it’s done in order to establish the boundaries of the scent, so as to better keep the trail.
The study indicates that there is a strong purpose for humans having precisely two nostrils: the human brain compares data it gets from each nostril to get clues about where a smell is coming from. The Berkeley study demystifies the theory that says human nostrils are too close together to get distinct signals.
Noam Sobel of the University of California-Berkeley says, “We debunked that”. He and graduate student Jess Porter and others reported their findings on the Web site of the journal Nature Neuroscience. The work will appear in the journal's January issue.
By revealing how noses locate smells, scientists hope to lay the groundwork for electronic noses that could detect hazards like land mines. The work was funded in part by the Army Research Office.
