How the nose sniffs out danger

March 28th, 2008 - 1:29 pm ICT by admin  

New York, March 28 (IANS) The human nose encounters hundreds of thousands of scents daily. Many of them are identical, so how do we learn to tell critical ones apart? A single negative experience linked to an odour rapidly teaches us to identify that odour and discriminate it from similar ones, according to a new study.

In the study, subjects were exposed to a pair of grassy smells, nearly identical in their chemical makeup and virtually indistinguishable.

Findings of the study have been published in the latest issue of the journal Science.

They received an electrical shock when they were exposed to one scent, but not when they were exposed to the other similar one.

After being shocked, the subjects learned to discriminate between two similar smells. This illustrates the tremendous power of the human sense of smell to learn from emotional experience.

Odours that once were impossible to tell apart became easy to identify when followed by such an event.

“It’s evolutionary,” said Wen Li of Northwestern University and co-author of the study.

“This helps us to have a very sensitive ability to detect something that is important to our survival from an ocean of environmental information. It warns us that it’s dangerous and we have to pay attention to it.”

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