The Scent of Desire
Rachel Herz's book The Scent of Desire: Discovering our Enigmatic Sense of Smell is hands-down the best summary of the modern understanding of the human sense of smell.
Dr. Rachel Herz is a leading olfactory researcher, inventor, and is an extraordinary communicator of the science of scent. She has a blog on the psychology of smell called Smell Life at Psychology Today. at Her book is a fascinating exploration of
- the mechanism of scent;
- the central role of neural perception;
- the relationship of taste, smell, and flavor;
- the primacy of scent among all the senses;
- the role of scent in health and disease;
- and much more than I can list here!
Here are just a few things you can learn by reading this book:
- Besides the strictly olfactory stimuli that are transmitted through the olfactory nerve (CN I), most smells also have a "feel" to them that stimulates the trigeminal nerve (CN V). For example, menthol feels cool and ammonia has a burning feeling.
- Smells that "stink" only have that effect if we learn that the smell is unpleasant. Herz notes that she loves the scent of skunk because her mother taught her that it was a pleasant scent.
What really stinks? What really smells great? Your first impression of a scent (such as associating it with a pleasant or unpleasant feeling) will usually stick with you forever.
- Students who learn something in the presence of a certain odor are likely to recall it more efficiently during the test if the same odor is present. (Perhaps we should have pizza sitting out during exams?)
- Your major histocompatibility (MHC) genes determine your unique "odorprint" that differs from everyone else. This odorprint is what is detected by dogs. But we also each other's odorprint . . . we seem to be able to distinguish people that are genetically similar to us and those who are genetically different. This talent in useful when trying to find a nonrelated sexual partner. Dr. Herz explains that smell is central to our sex life . . .
- The product OdorScreen blocks the scent of decaying tissue (as experience by rescuers at disaster sites) by stimulating adaptation of the olfactory receptors involved before the stink of decay is encountered—thus the nauseating scent is not smelled. Herz describes how this works in the book. Here's a clip from CSI . . .
- When you smell food coming toward your mouth, you experience orthonasal olfaction. When you smell it again as you chew and swallow it (as the scent enters the nasal cavity via the pharynx), you experience retronasal olfaction. Click here for an image and brief explanation of this phenomenon. Retronasal olfaction is in large part what we often think of as taste. In case you need some off-putting scientific jargon at your next dinner party.
- People that lose their sense of smell often become extraordinarily depressed and despondent . . . much more so than when people lose other senses such as sight or hearing.
- We often use scents, more than photos or recordings, to recollect people who are absent from us. We recognize family and friends by smell more than we consciously realize.
OK, I'm going to stop there. The books is just FULL of interesting stories that convey fascinating information.
And now for something completely different. . . we apply what we've learned to "real life."