The sense of smell is such a powerful memory enhancer that at one time people in the training business tried to capture its potential.  However, the difficulty with using smell to help people retain what they had learned is that very few smells are considered neutral. Most smells carry an association, either with something pleasant, or unpleasant. And people do not always agree on feelings evoked  by particular smells.

For example many people enjoy the pungent smell of vanilla, especially combined with sweet overtones such as in vanilla cookies. However, long ago when I was in college, I was approached by a shuffling, old man in a grocery store as I pondered which fresh fruit would best supplement the rather insipid, college cafeteria food. There was a familiar pungent smell exuding from him as he kept pestering me.  Then, I realized what it was when the stock boy shooed him…