Biology

The Human Nose Can Detect 1 Trillion Odours

According to a recent study in the US, the human nose can detect one trillion different smells, far more than we first thought.  A long held belief was that we can sniff about 10,000 smells. This new estimate has been published in “Science” and suggests that the human nose actually outperforms the nose and ears, in terms of the number of stimuli that it can tell the difference between.

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The human eye actually uses three light receptors to work together and see up to 10 million colours, whilst the ear can hear almost half a million tones.  Until now it was believed that the nose, with 400 receptors could detect only 10,000 different odours. Apparently they set out to test this idea dating back to 1927 that actually was never scientifically investigated. They devised experiments to see how good people are at distinguishing between cocktails of 128 different odour molecules, representing a large range of smells from grass to citrus. These molecules where mixed into groups of 10,20 and 30 to create unfamiliar smells.  The 26 people were then asked to identify a scent from three samples – two that were the same and one that was different. Scientists say that this is the first time we can really say how good humans actually are!

 

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