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Binocular vision gives us a 3D perspective, and two ears let us locate the direction of a sound. But why two nostrils? (continued)

Richard Gregson
via email

For both the hunter and the hunted, knowing the direction of the source of a smell is essential. The directional ability of smell location by humans has been known for a long time. Georg von Békésy, who received the Nobel Prize for his work on hearing, also determined that the direction of an odour can be established by humans to about 7 degrees. Remember that when you feel inclined to break wind in an elevator.

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