Why have spices always been so precious to human beings? Consider that in Roman times, a pound of cinnamon oil cost a Centurion’s salary six times over, according to NYTimes writer Alex Halberstadt reporting on spices.

For one thing, the pre-Renuzit world, certainly the first cities, were ripe with putrefying odors.

Secondly, aromas lock into the emotions like no other sensory information. Olfactory messages are an expressway to your heart, with thanks to The Soul Survivors circa 1967. Srini Pillay, a psychiatrist at Harvard Medical School who studies the neurological effects of spices, comments that olfaction is the only sense that communicates directly with the cortex in the brain without pausing at the relay station — the “switchboard”–of the thalamus.

This is part of why smells have such a potent effect on how we feel, and why essential oils in aromatherapy products for the shower can quickly improve mood and alter energy levels.