WELL, IN THE MODERN WORLD, IT’S LESS USEFUL AND MORE LIKELY TO BE ANNOYING: People’s sense of smell may be declining, study suggests. And some of it is just mental filtering. Most people’s sense of smell is much better than they think. Richard Feynman used to have a parlor trick where he’d have someone take a book off a shelf and put it back. Most people could tell which book by smelling the shelf, and which person by smelling hands.

Most people can see and hear a lot more than they realize too. Modern society encourages filtering this data.