Has our sense of smell evolved based on what is good and bad for us?

Has our sense of smell evolved based on what is good and bad for us?

Something that smells so rotten surely can't be good for you, right?


Asked by: Tom Russell, Democratic Republic of the Congo

Yes, we have evolved a higher sensitivity to smells that indicate poison or danger. Rotten fish, for example, smells so disgusting because it's teeming with bacteria, and we've evolved to interpret the odour as a warning that eating the fish would likely make us ill.

It's true that we become more sensitive to some smells after we learn to associate them with a bad experience. But cadaverine and putrescine, which are produced by decaying corpses, smell revolting even if you have never smelled a dead body before. This aversion is shared with lots of animals and evolved at least 420 million years ago.

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