People know how to sniff for traces

People also have the ability to trace the smell on a lawn like a crane, and this ability will be significantly improved through training, US scientists claim.

Jess Porter, Noam Sobel and scientists at the University of California, Berkeley (USA) pour chocolate solution along a 10 m long track on a lawn. They then asked 32 volunteers to use their noses to follow this path. The results were unexpected: Two-thirds of the volunteers discovered the chocolate solution's path.

The team selected 4 volunteers and taught them how to sniff for 2 weeks, 3 days a week and 3 times a day. After training, these 4 people can determine the chocolate solution's path with almost double the accuracy of the previous one.

Experimental results help scientists better understand mammalian smelling behavior. Many biologists believe that mammals can determine the direction of odor by comparing the lightness of odor on each side of the nostril, just like the direction of sound with two ears. However, many biologists object to this hypothesis.

Compare sugar smelling chocolate of people (right) and of dogs, chickens (left) through the field (Photo: Newscientist)

Many species, such as lobsters, determine the direction of odor by brandishing an antenna whenever a smell is smelled. But many experts believe that the nostrils of mammals are too close to determine the exact direction of the odor by distinguishing its darkness in each nostril.

Porter's group asserted, in fact, two nostrils took air from two separate areas, not overlapping each other, in the space in front. Researchers say the ability of volunteers to sniff at the lowest level when a nostril is blocked and when they are wearing a device that functions as a virtual nostril. This device mixes two air currents through two nostrils into a single thread.

"It seems that the mechanism of determining the smell of animals, from insects to humans, is the same," said Matthias Laska, an expert in animal sensory research at Linköping University (Sweden). identify.

When asked whether humans are capable of sniffing as well as dogs, the researchers think the biggest difficulty for us is not being able to move quickly when hitting the ground. They plan to find out if humans can trace the smell when standing upright.

Viet Linh