Increasing olfactory memory strengthens memory in general.

Taste and scent detection greatly overlap.

Our olfactory system, which originated millions of years ago, evolved to detect small changes in the chemical composition of the environment and thereby serve as a protective mechanism. Such a use remains operative today by enabling us to smell telltale odorants that may precede such things as an explosion secondary to a gas leakage.

But the olfactory system comes with good things too: Responding to such pleasurable odorants as flowers or the aromas of newly cut grass. Chemicals are the key. But a smell can’t always be predicted from its chemical composition or the order of its molecules. D-Carvone smells like caraway seeds, whereas its mirror image, L-Carvone, smells like spearmint. One scent stimulates a specific firing pattern in one part of the olfactory bulb; other molecules stimulate other firing patterns, with most molecules failing to stimulate any pattern at all.

But when a scent—a specific brew of chemicals—arouses our attention, our response differs according to the molecules involved. Smelling bergamot in our Earl Grey tea stimulates one activation pattern in the olfactory bulb; smelling Lattafa Asad perfume stimulates another. Scents are composed of chemicals with unique chemical signatures corresponding to the medley of chemicals in a particular odorant.

Unique among the five senses, olfaction is the only sensory receptor that links directly to the limbic system, which processes emotion. As a result of this direct connection, smell surpasses any of the other senses in evoking emotions.........

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