Why can people distinguish between caraway and spearmint even though their odor molecules are mirror-image forms of carvone?

People can distinguish between caraway and spearmint because they are composed of different enantiomers of the molecule carvone. While enantiomers are mirror-image forms of the same molecule, they are chiral, meaning they are not superimposable on one another.12

The human olfactory system functions through specific olfactory receptor proteins that act like a lock and key; a molecule must fit into a specific "pocket" on the receptor to trigger a response. Because biological systems are themselves chiral—composed of specific, handed amino acids—the receptors interact differently with each mirror-image form of carvone. Just as a right hand interacts differently with a labeled object than a left hand would, the two forms of carvone fit into different receptor pockets, stimulating distinct sets of receptor cells and allowing the brain to perceive them as unique scents.312