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Eye on Psi Chi: Winter 2014
From Desire to Disgust
With Rachel Herz, PhD

By Bradley Cannon, University of Tennessee at Chattanooga

Do you feel the same sensation when you hear about a dirty politician as when you step on a worm with your bare feet? A 25-year expert on the psychological science of smell, Dr. Rachel Herz of Brown University (RI) has published books, numerous research articles, interviews, and more. She works as a consultant to some of the world’s largest aromachemical companies, testifies as an expert witness on smell, and runs two companies, Sniffiggle and RSH Enterprises. Her work has been featured on the Discovery Channel, ABC News, the BBC, National Public Radio, The Learning Channel, and Scientific American.

In 2008, Dr. Herz’s research took a fascinating leap from the study of desire all the way to the study of disgust. About that transition, she laughs and says, "Because I wrote The Scent of Desire: Discovering Our Enigmatic Sense of Smell, a PR person convinced me to be a judge for the National Rotten Sneaker Contest in Montpelier, Vermont alongside the local superintendent and other officials. One of the judges works for NASA and assesses the scent of things before they go into space, and I thought it all sounded cute, so I agreed.”

However, in the months before the contest, Dr. Herz received countless horrified reactions. Many people told her that she could not even imagine how bad the shoes were going to smell. They couldn’t believe she would do such a thing to the extent that she began to worry about her decision too. However, she says, "When I finally got to the contest, the shoes were definitely bad, but they weren’t as bad I had thought. That’s when I realized how much the mind influences what we perceive to be disgusting.” That’s what inspired her to write her next book.

As Dr. Herz began researching for That’s Disgusting, she quickly found that the literature on disgust, and particularly the subtopic of the morality of disgust, is huge. One question frequently asked is whether people feel the same sensation when they hear about a dirty politician as when they step on a worm with their bare feet. On this matter, Dr. Herz believes it is not the same.

To further explore the idea that our culture affects how we feel, not only in relation to smells but also in relation to taste, Dr. Herz conducted a study to see whether moral and visceral disgust would be responded to similarly. For this research, she divided participants into three groups (nontasters, tasters, and supertasters) depending on how strongly they reacted to PROP taste papers supplied by taste expert Dr. Linda Bartoshuk (see Beckman, 2004 to learn more). The results indicated that, indeed, supertasters were more responsive to visceral disgust, but not to moral disgust. In fact, moral disgust sensitivity had no relationship with taste sensitivity, so she concluded that moral disgust does not have the same fundamental connection to taste as visceral disgust does.

"In my experience, it is true that the rejection of some bad tastes, specifically bitter tastes, occurs due to an innate rejection of the taste. For example, if I put something bitter on your tongue and on the tongue of a newborn, your reactions would be the largely the same. This is an adaptive response, because most bitter things are poisonous, and we don’t want to ingest poisons. However, if I asked you to eat seal eyes—a delicacy to the Inuit people, your reaction may be the same as tasting something bitter, but an Inuit may be very pleased. This is because of the meaning of seal eyes to you versus the Inuit. You likely find the idea repulsive, but to the Inuit, it’s a treat. This shows how culture and learning determine most of what we find to be disgusting or not.

The role of meaning ties the emotion of disgust with our perception of smells and what odors we like and dislike. The aromas we like are those which we have acquired a positive meaning toward, and the ones we don’t like we have learned a negative meaning for. Our associations to odors also determine how we will behave or physiologically respond to the presence of a given smell. For example, Dr. Herz has found that an aroma can indeed make you feel calmer because of your cultural and personal association with what you smell, but not, as many aromatherapy proponents suggest, because the scent has drug-like power over you. Dr. Herz says, "If you have formed an invigoration association with peppermint aroma, it can in fact enliven you—it may increase your reaction time, or enable you to run faster or even do more pushups. By contrast if you don’t have any associations with lavender it will not have any affect over you, or if you have a negative association to peppermint it could make you feel unmotivated.”

Moreover, the meaning of odors is very strongly guided by language and we tend to believe our eyes and ears more than our noses. For example, one study subjected participants to either (a) neroli, which in aromatherapy terms is supposed to be stimulating, (b) lavender, which is construed as relaxing, or (c) no scent at all. All participants were told that a scent was present, though it could be very mild so that they might have difficulty perceiving it. Subjects were never told the name of the odors and instead were either told that the scent present (even when nothing was there) was either stimulating or relaxing. The results showed that, regardless of what they were exposed to including clean air, what they were told the scent was supposed to do them is what happened. If they were told the scent was stimulating, their heart rates went up, and if they were told that the scent was relaxing, their heart rates went down.

Outside of the lab or classroom, Dr. Herz sometimes applies this knowledge about human perceptions of smell as an expert witness. Mainly, this occurs when someone loses their sense of smell, and the insurance company does not want to pay much for compensation. "That’s when I’m brought in to demonstrate that this person’s life has been significantly derailed. Many people are much more disturbed by losing their sense of smell than most of us would predict.”

Another situation that leads Dr. Herz to the courtroom happens when people complain about a malodor, usually from an industry they don’t like being in their neighborhood. However, these cases are not always simple. "What’s interesting is that sometimes there’s no odor at all. Sometimes people see smoke towers emitting odorless steam, and they just think they smell something they don’t like. In these cases, I explain to the jury how and why people have this false belief. I explain that they aren’t crazy but that their perception is due to a psychological response, not due to the physical presence of a malodor.”

Of course, knowing that our reactions are so easily manipulated has led many to wonder if it is possible to manipulate our senses intentionally. In other words, how can I increase my sensitivity to smells?

In response, Dr. Herz says, "There’s a very simple thing you can do, and that’s to pay more attention. Literally stop to smell the roses because we’re constantly surrounded by smells, though we don’t usually focus on them unless we’re eating or testing perfume. By actually taking the time to recruit more of the brain, you will be able to smell more and even perceive things at lower intensities. You just have to focus your mind on what smells are around you because there really is no such thing as an odorless environment.”

In order to help you improve your sense of smell, especially in the kitchen, Dr. Herz helped to create a company called Sniffiggle. The leading product of this company is The Educated Palate, a kit of 25 vials of herbs and spices in a tasteless edible oil. "People use this product by opening a vial and smelling and tasting the oil inside, and then they learn the connection between a specific scent and flavor and the name of what it is; rosemary, oregano, or whatever else. The Educated Palate can be used by gourmets as a fun way to augment their palate and culinary skills, but it is most helpful for chefs so that they can build a consistent language to communicate with each other. That way, when one person talks to another or comes up with a recipe, not only can they practice by mixing the scents from the vials, but they can also have the necessary language to communicate.”

"The idea came from the fact that no one teaches you to smell and tell— we just go along and, through experience, learn to associate a label with a scent, but often our experiences and labels are very different from each other. Are we smelling different things when you call garlic tomato sauce but I call it garlic or do we just have different names for the same scent perception? So far, we’ve gotten really good feedback from chefs and others. It’s a great learning tool, and anyone who enjoys cooking also likes it because it enriches the flavor creativity of their culinary world.”

Dr. Herz isn’t the only one who wants to influence your sense of smell. She has also worked with numerous companies on various levels. She’s spoken with chemists in an educational format about emotion, memory, and language. From a PR perspective, she’s written articles and taken part in interviews. Right now, she’s working with Glade, who want to rebrand themselves away from the image of removing bad smells and toward the image of creating best emotions through scent.

As anyone can see, Dr. Herz is involved in many unique projects, which is because she was inspired to develop many skillsets when she took a year off before graduate school to travel through the Middle East and Europe. "When I was abroad, I had a number of really incredible and eye-opening experiences with seeing how people in poor areas lived. It woke me up to the fact that I am super privileged, and that I hadn’t been taking that very seriously. It made me realize how important my next steps were, not just to do justice to myself, but to the privilege itself. I realized that if I didn’t have a passion for it then I shouldn’t be doing it..”

"While I was traveling I found out that I have been accepted for graduate school at the University of Toronto. The research I first started doing was because I was offered money from a specific supervisor to be his student, and this was his research interest. But I soon realized that what I was doing wasn’t really floating my boat. I learned that this wasn’t for me, so I got out. I switched around a lot, and actually that experience really helped because it broadened my knowledge-base and because you shouldn’t waste your privilege on something you’re not interested in.”

Dr. Herz’s most recent article on moral disgust and taste had just been published in Behavioral Neuroscience. (Herz, 2014). Currently, she is working on a new book on the neuroscience, psychology, and culture of food and eating in 21st century North America that will be published in 2016 by W.W. Norton & Co. She’s teaching a course at Boston College on this topic too, and development has begun for a more advanced version of The Educated Palate and a version for wine tasting too. She looks forward to all of these things and encourages you to do the same. She says, "Don’t be afraid to change your mind and try different things. And don’t force yourself to stay working at a research topic if you don’t have a passion for it.”

Beckman, M. (2004) A matter of taste. Are you a supertaster? Just stick out your tongue and say "yuck.” Retrieved January 31, 2014, from

Herz, R. S. (2007). The scent of desire: Discovering our enigmatic sense of smell. New York, NY: William Morrow/HarperCollins Publishers.

Herz, R. S. (2011) PROP taste sensitivity is related to visceral but not moral disgust. Chemosensory Perception, 4, 72–79. doi:10.1007/s12078-011-9089-1

Herz, R. S. (2012). That’s disgusting: Unraveling the mysteries of repulsion. New York, NY: W.W. Norton and Company.

Herz, R.S. (2014). Verbal priming and taste sensitivity make moral transgressions gross. Behavioral Neuroscience, 128, 20–28. doi:10.1037/a0035468Insert text

Rachel Herz, PhD, is a neuroscientist and leading world expert on the psychological science of smell. She has been conducting research on the sense of smell, emotion, perception, motivated behavior, and cognition since 1990. Dr. Herz has published over 70 original research papers, coauthored several college textbooks, and is an adjunct professor at Brown University and part-time faculty at Boston College. She is also a professional consultant to various industries regarding smell, taste, food, and flavor, and is frequently called upon as an expert witness in legal cases involving olfaction. Dr. Herz is the author of The Scent of Desire: Discovering Our Enigmatic Sense of Smell which was selected as a finalist for the 2009 AAAS Prize for Excellence in Science Books, and That’s Disgusting: Unraveling the Mysteries of Repulsion, which received numerous accolades and analyzes the emotion of disgust from culture to neuroscience. She is currently working on a new popular science book exploring our psychology and passion for food.

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Copyright 2014 (Volume 18, Issue 2) by Psi Chi, the International Honor Society in Psychology



Eye on Psi Chi is a magazine designed to keep members and alumni up-to-date with all the latest information about Psi Chi’s programs, awards, and chapter activities. It features informative articles about careers, graduate school admission, chapter ideas, personal development, the various fields of psychology, and important issues related to our discipline.

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