Out of all the senses, smell is probably the one that strongly brings out emotional memories and experiences. Closely related is our sense of taste, making our experience of food much more potent. Joining us today to dig deep into the future of smell and taste is Dr. Rachel Herz, a neuroscientist and world-leading expert on the psychological science of smell. She helps us understand the variables that affect our relationship with food, particularly that of smell and taste, so we feel the power and control over it rather than food controlling us. She also discusses the difference between supertasters and non-tasters, how taste is defined by genetics, why some people have an aversion to certain smells, and the debilitating effects of losing your sense of smell. COVID has undeniably reminded us of the value of our sense of smell and taste. And Dr. Herz is someone who helps propel the science and research that could shape the future of this area. Tune in as she tells us more about the science of smell and taste and what it can do to better health outcomes.


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The Future Of Smell And Taste – A Conversation With Dr. Rachel Herz

We have Dr. Rachel Herz, who is a neuroscientist and expert in the field of smell, which is something that I’m particularly interested in. Dr. Herz, why don’t you tell us a little bit about how you got here and what it is we’re going to be talking about?

I had one of those circuitous paths of least resistance. Nothing was straightforward. Although I tell the students all the time, “When you do a retrospective on your life history, the narrative makes sense. When you’re in it at the moment, it’s complete confusion and chaos.” My background was in Biology and then merged with Psychology. At the time, there was no such field as Neuroscience. What I was doing was Biopsychology.

After doing an undergraduate degree, taking a year off, and not sure what I was doing with myself, working and traveling during that year, knowing that I was going to graduate school and somehow in this Biopsychology dimension. I’m also Canadian and I was doing this at the University of Toronto, in a lab that was studying spatial memory in black-capped chickadees or birds. I realized while I was doing that research that although it was interesting and I had a fantastic grounding and evolutionary theory and biology during that year, which was important and has stood me well and been a very guiding force throughout my full career that birds themselves, nevertheless, were not completely floating my boat.

In the dark hours of when you’re a graduate student and feeling like you need the passion to keep yourself going, I recognize that this wasn’t for me. What I was interested in was humans and somehow bridging the gap between psychological processes and biological mechanisms and figuring out how they are interwoven. During my PhD research, I read a paper where the authors used smell to manipulate mood. It has never been done before. They gave this one-paragraph explanation about the evolutionary position, anatomical position, and why it was the critical sense to influence emotion in this non-cognitively loaded way.

All of a sudden, the light bulb went off and I thought, “I can make this connection through the sense of smell and look at something I had always been interested in,” which is the connection between smell and emotional memory. Fortunately, my supervisor, although not knowing anything about this topic, was generous enough to say, “Here’s the Roku. Hang yourself. I can’t help you, but go right ahead.” I went to Brown University, which is where I have an adjunct position now.

FSP - DFY | Smell And Taste

At the time, the only person who was studying the Psychology of Smell and the father of it was there. I met with him. He gave me a stack of papers, books, and so forth. I met other people. I went to International Flavors & Fragrances in New Jersey and said, “Can you give me some materials so that I could do my research?” We joke around, “Who is that crazy Canadian graduate student who landed on our doorstep one day?”

I got lucky. I developed a paradigm where I compare sensory experiences in different modalities. For instance, the scent of popcorn versus hearing popcorn kernels popping, reading the word popcorn, singing popcorn, feeling popcorn, and so forth, and pairing them with emotional scenes that people then had to remember several days later. I looked at the accuracy of those memories, a couple of other dimensions relating to that, the emotionality of those memories, and some other dimensions relating to emotion.

What I found was that there was no difference in accuracy. You’re as accurate or not. We’re calling what the image was, whether it was a scent, sight, sound, etc. That’s the trigger, but if the cue that’s recalling, the memory for you is a scent, that memory experience is much more emotional. That separates our sense of smell from other sensory experiences and other memory experiences overall, a special connection between emotion, memory, and emotional experience overall. In any case, that was the beginning. Many years have gone by now, and I’m still working in this sphere as well as relating to many others connected to it over this time.

Let me ask you a question about that. How are you measuring an emotional experience? When you say one experience is more emotional than another, how is that gauge?

In my original studies, I did it both through the written descriptions that people gave and analyzing the text for adjectives relating to emotion, also doing simple scales and people rating the memory for how emotional it was and some other measures that are pure subjective writing scales. Subsequent to that, I have also done FMRI studies looking specifically at how the amygdala is activated during a memory triggered by a smell compared to recalling the same event through a visual modality and also looking at behavioral measures connected to this. How do people behave in the presence of a scent that’s triggering an emotion? Also, looking at the behavior as a measure of their emotional state.

I understand the idea of being a more emotional experience. One of the things that I’ve heard, and I don’t know if this is accurate, is that the smell memory lasts for much longer than other memories. Is that accurate or not? Were you saying that they weren’t the same?

That’s different from accuracy. In the studies I’ve done, I’ve looked at autobiographical memories from people’s past, but in this particular study, there was a 3 and 2-day lag. The time factor wasn’t involved. However, it is the case that memories that are connected to a smell tend to be from further back in our past when it’s not a biographical memory and they tend, even when they’re learned newly, to last longer than memories that are connected to something visual something, auditory, and so forth.

The reason for that has to do with the distinctiveness of scent because in our daily lives, we encounter many sights, sounds, and all kinds of other information bombarding us. Many of it is the same. For instance, when this is the case with smell, it’s also the case that these memories don’t last particularly long and they’re not particularly poignant. For example, the smell of coffee is unlikely to be associated with a specific autobiographical point from many years ago in your past. Because you experience coffee so often, it gets overwritten, rewritten, and reconnected all the time, but it’s often the case that we will experience a particular set only in one situation.

It’s only until we come across that scent again that it brings us back. It has to do with the distinctiveness, rarity of the scent, and the lack of being overwritten over time. The fact that when we are first experiencing smells is when we’re first learning about them. Many of our first experiences with smell come from childhood like with everything else. With everything else, it tends to be repeated many times and lost in the wash, whereas, with smell, it tends to not get overwritten nearly as much and bring us back to earlier times in our lives.

I remember I was walking along and I had a distinct smell that reminded me of my grandparent’s house. I hadn’t been there in 30 years, but I still remember that exact smell of a closet in their house long ago. That experience was fascinating for me because I don’t remember very much from that young of an age.

Honestly, if you were to ask me my elementary school teachers, I couldn’t rattle them all off for you. There’s only a handful that had a profound experience with me that I could remember but that smell lasts. It wasn’t even that same scent specifically. It was something that reminded me of that scent, which I thought was interesting because you don’t have that experience with other memories.

Another thing that I wanted to talk with you about is the idea of not only the emotional or memory experience but specifically how it relates to taste because I know that’s a big focus of your work. It’s something that I’ve been diving into myself. I read this interesting book, Neurogastronomy. It was talking about all of the different chemical reactions from when you experience the taste and how it goes through and is interpreted by the brain. The smell receptors are totally different from other receptors. It’s something that’s not as well Illustrated in their exact physiology as other receptors. Tell me a little bit more about that, about how smell and taste are interrelated.

I want to give a little explanation to the book Neurogastronomy, which was written by Gordon Shepherd. He coined that term. Unfortunately, he passed away, but he began the field of Neurogastronomy. I’m on the organizing committee for The International Society for Neurogastronomy, which he formerly was involved with and started. He has left a real legacy in this field.

What is neurogastronomy? It is the combination of a variety of different life experiences, commerce, agriculture, nutrition, medicine, etc., the senses and neuroscience of how it is that we perceive food and flavor. To go back to your point about taste and smell, taste, as a sensory system, is very simple. It’s salt, sour, sweet, bitter, and Umami depending upon the arguments and the camp that you’re in. That’s it.

From the point of view of the sensations that you get purely from your mouth, that is to do with your tongue, the receptors that are directly inside your mouth, those are very simple experiences. Everything else we experience when it comes to the experience of food is through the nose. I should say that there’s also the case of the feel of fattiness and creaminess or the burn of a hot pepper. Those are tactile sensations that also occur within the mouth.

In terms of telling the difference between cured bacon and cured salmon, that is through our nose because otherwise, the taste is salty and maybe it also feels a little fatty. Everything else that we experience has to do with our sense of smell. That’s because there are two roots to smelling. We think about smell normally in terms of sniffing like, “I’m sniffing the rose,” or something like that. That’s the scent coming through our nostrils and hitting the olfactory epithelium, which is where the sensory neurons are also right at the level of our eyebrow. That’s coming from our nostrils directly as we inhale.

Everything else we experience when it comes to the experience of food is through the nose.

There’s another route that also brings aroma chemicals to the sensory neurons in the same place. That’s through our mouth. That’s because, as anyone knows, from having a cold, maybe bad allergies or something like that, when your nose is blocked, food doesn’t taste right or maybe when you were a kid and like making your sibling or your friend laugh and they had something in their mouth and then it came out their nose, if you’ve ever had any experience relating to that, then you know that there’s this open system between our mouth and our nose.

This open system this open airway passage, which is at the back of the mouth, enables us to experience the aromatic chemicals that are from the food we’re eating at the same time as the taste and it has to do very critically with being able to breathe. If you can’t breathe, you’re not going to be able to experience this. We inhale while we have food in our mouth and the aromatic chemicals go up through the back of the mouth, into the nose, and get to that same spot with the sensory neurons, then we exhale. That whoosh of air out is creating that sensation that we get the full aroma. It’s happening simultaneously as we’re experiencing salty, sour, sweet, and whatever.

The brain then fuses those experiences together and we get a flavor, but because the food is in our mouth physically, we always think that it’s coming from our mouth. Because we know that taste is in the mouth, people always say like, “The taste of bacon, chocolate, and caramel salted ice cream,” but the only thing that you’re tasting is salt, sweet, bitter, or sour. Everything else comes from our noses.

If you have your nose blocked or people lose their sense of smell, which has happened so much more frequently since COVID or as a function of COVID, then that experience of the food is lost. There’s no way to tell the difference between an apple and a potato, for example, if you have your eyes closed because the sensory experience is only this bland, slightly sour, melee, or slightly sweet experience, but everything else comes from your nose.

I like the distinction he made in the book between orthonasal smell and retronasal smell. I felt like that was something that clicked for me. Now, I feel like I have some awareness of it. My experience with food is different. It’s much more layered and I enjoy so much more about it. That’s something that I credit this book for, but I know that’s some stuff that you’re looking into also. Can you tell us about the enjoyment of food and how smell relates to that?

My book is called Why You Eat What You Eat: The Science Behind Our Relationship With Food. It breaks Neurogastronomy, the book that you read down to them so much more approachable and goes into all the different dimensions, not just the sensory and the neuroscience but also the emotional, social, environmental, and much more of the experiential end of things. There is a lot that goes into our emotional experience and our enjoyment of food. It depends on 1,000 different things at any given moment, for example, who you’re eating with. How does the food look? What is the situation for eating it?

Is it a special celebration? Is it that you’re giving yourself a reward for having done something or giving yourself a special treat? Is it food that someone you love prepared for you, like the comfort food idea, or eating food because it’s connected to the food that you ate when you were a child, which is comfort food or you have to eat a meal with people that you don’t like? Is the situation something where the music’s loud and clamoring and you’re like, “I have to get out of here?”

There are many features that go into our experience of food that we often have no idea about. One of the things that I wanted to do in my book is to give people the awareness, knowledge, and understanding of all the variables that are affecting them so that they can feel that they have power and control over their relationship with food and then don’t feel like food is controlling them. Understanding all the different vectors that are hitting us all at once when we’re experiencing something goes way beyond sweet and the smell of chocolate, for example, if you’re eating something chocolate.

For example, sugar and fatty foods trigger the reward center in our brain and can also trigger the analgesics that have an opioid system in our brain. If you stub your toe and have some high-end European chocolate that’s both sweet and high in fat, there’s an analgesic effect to that. Likewise, if you’re in a depressed state emotionally, food does not taste as fatty or as sweet, so we can eat more of it in a way to get that sensory experience for craving because the neurotransmitters that are being activated as a function of our being depressed suppress the sensations of pleasure like sweetness and fattiness.

The idea of supertasters and the difference in skill level it tastes is super interesting. I wouldn’t say skill level, but there are people who are supertasters. They tend to have a better BMI and overall physiology when it comes to that stuff. I wonder if it’s because people who are not able to have as strong of a taste sensation experience what you’re experiencing where it’s not as fatty or sugary to them. Therefore, they eat more of it to get that same satiation. Do you have any research in that field at all?

Supertasters, tasters, and non-tasters are something you’re born with. It’s purely genetic. There’s nothing that you can do to hone that or get that in any changed way. Interestingly, though, what you’re saying, most chefs tend to be supertasters. However, I know of one very famous chef who is a non-taster and that he feels has helped inform him because of the way that it breaks down and in the population in terms of the percentage of people who are tasters, non-taste, or supertasters is approximately in thirds. It depends. There are a couple of other things.

Racial genetic backgrounds can alter this in terms of specific ethnicities and populations. There’s a little bit of a difference also between males and females, but in terms of a gross sense, it’s 1/3 of the population. The fact that the majority is not a supertaster, means that, for instance, people coming to your restaurant are not potentially tasting the food or experiencing the food the same way as a chef who’s a supertaster is.

He feels like being a non-taster gives him a different perspective. Regardless, what you’re saying is correct that the extensory experience of food for a super taste or as much more intense. Salty is saltier, sweet is sweeter, and bitter, in particular, is much more aversive. Fattiness is much more creamy, the burn of hot pepper is more stinging, and so forth. That tends to mean that people who are supertasters need less of whatever it is to get the maximum experience for them.

That being said, interestingly, the one area where supertasters overdo it is with salt. From the point of view of health factors that connect to being a supertaster or non-taster, it is the case that overall, BMI tends to be lower in a healthier range for people who are supertasters. This is on average compared to non-tasters. Non-tasters also possibly have the potential to be more susceptible to certain drugs of abuse like alcohol and smoking because both of those substances are burning in the mouth. If you didn’t have very much burning, then when you were a kid, it was easier to empty your parent’s vodka than it is if you’re like, “That hurts. I’m not going to do it.”

Those kinds of things tend to be where the health vulnerabilities of non-tasters fall, but supertasters, because they find bitter aversive, avoid the healthy leafy greens. They’re more susceptible to several types of cancers, especially cold cancer. Because saltiness blocks bitter taste, they are used to putting a lot of salt on their food, and using a lot of salt can lead to hypertension. There are non-perfection aspects of vulnerabilities for being a supertaster versus a non-taster. Tasters, which are the Goldilocks middle group, probably are the best overall because they get the taste. It’s not quite as strong as the supertasters, but they don’t have the substance susceptibilities that some non-tasters could have.

What’s interesting to me is that taste is also defined by genetics. I feel like my experience with vision, touch, and all of these other senses that we have, even hearing, is pretty well regulated. Granted, there are outliers like color blindness and things like that, but it’s pretty consistent throughout the population. There’s much variability when it comes to taste. Do you have any comments on that?

There’s not that much variability with taste. The genetic component has primarily to do with supertaster or non-taster. That has to do with a difference of an allele at one place on a particular chromosome. You either have 2 sets of 1 heterozygous, 1 of each, or 2 sets of the other. However, smell is the most vastly variable genetics of any experience. Everyone has a unique nose. What I mean by that is that the specific receptors that are expressed in every individual for being able to detect smells are ever slightly different because of the genetics behind it for every single person except potentially if you have an identical twin.

This is something that makes a sense of smell individualistic. The sense of taste, because it’s simpler from that perspective, other factors are involved with some of the genetics behind taste. Genetically speaking, taste is still relatively simple but combined with smell, because that’s what food is and flavor, you do get this huge variability.

The perception of chocolate that you and I are both consuming is not going to be the same for each of us, even if we’re both supertasters, because our sense of smell is different, and our experience of the flavor is going to be at least slightly, if not even more than that, different between the two of us, plus our subjective experiences go behind what it is that led us to liking or disliking these flavors, foods, and so on are going to have an impact, the circumstance in the situation, and a lot of other things in how hungry we are of course.

When you hear about findings like cilantro tasting differently to different people or Umami being different in different populations, is that more due to smell or taste?

Umami is taste. The reason why people either love or hate cilantro is because they are missing or are not missing a specific olfactory receptor. The cilantro experience is all about smell. Interestingly, people who hate cilantro are missing a specific receptor. They only get the soapy notes of cilantro, whereas people who have the receptor that’s responsible for the herbaceous delicious quality, if you have it and you like cilantro, have that receptor which blocks most of the soapiness. They don’t get so much soapiness.

That’s a very specific attribute. Are there other specific attributes of smell that have been identified like that?

There’s a whole set of specific anosmias. That is to say, you have a normal sense of smell, but it’s like being color blind for something very specific. You can’t smell freesia flowers or one of the most common ones in a certain type of musk. There’s a whole set of these things. A slightly funny example, people who eat asparagus, and afterward, if they go to the bathroom, may or may not notice a particular scent. That has to do with two things. 1) Whether or not they have the olfactory receptor to detect that scent, which is in pee, and also whether or not they’re what are known as expressors to say that they metabolize that asparagus into the constituents that lead to this particular scent. That’s genetic as well.

If you are both an expressor and you also have the olfactory sensory neuron to detect it, then after asparagus, you can make jokes with your friends, but if you don’t metabolize it that way, which is one particular thing, you may not know that or not or don’t have the receptor, then it’s going to be something different. Not to get gross, but if you want to find out if you were not metabolizing or if you didn’t have the olfactory receptor, someone who you know that does metabolize asparagus can go to the bathroom and then you can walk in afterward and test your nose.

It’s super interesting. It’s something that I hadn’t thought of before until I happened to come across your TED Talk. I did this deep dive into it because I feel like in my area of expertise, it is the head and neck. I feel like it’s a very often neglected, A) Sense but B) Area of Understanding. For example, if somebody comes in to see me and has a facial fracture, and then they lose their sense of smell because of that, it’s something that they lose and move on. It’s not given the credit that it’s due. I didn’t realize the depth of the human experience that was determined by smell.

I appreciate you getting the word out because I feel like, especially in 2023, the whole purpose of this show is to look toward the future. One of the things that has been a common thread is the dynamic of the human experience is going to be increasing a lot of this technology that’s coming down the road is going to make us more hopefully connected and more time with our family and friends. That’s the best-case scenario, but then there are whole subjects that are not given what they’re doing. Smell is one of them.

The whole reason I got into this is because the Nobel Prize was given to somebody who determined these smell receptors. I didn’t know anything about them. I did a deep dive into it. That’s how I got from one point to the other but a very secure circuitous route similar to what you’re saying. Have you noticed a lot more focus on smell or is it still very much underrepresented?

A couple of things I want to backtrack a little bit on what you’ve said. First of all, yes. Linda Buck and Richard Axel did that work, published, and sold when I first started my PhD research. It’s very gratifying that they got the Nobel Prize in 2004 for this discovery of the genetics of the olfactory receptors. What you’ve said about your experience with patience is meaningful to me because my first book, which is called The Scent of Desire, came out of this.

It was the first time I was ever an expert witness, which was for a woman who lost her sense of smell in a car accident. That was pretty bad and she’d gone through several reconstructive facial surgeries as a function of being in this traumatic car accident. By the time I met her, which was about a year and a half later, she was all put back together again but had realized that the damage that had been done in this accident and I don’t know if maybe part of it was also to do with the surgery, probably not or to do with what happened in the accident itself, but in any case, she was left without a sense of smell.

Her entire life was turned upside down and going downhill very quickly. It was all to do with her smell loss. She was beside herself because she had never put any stead into her sense of smell before. She’d never paid any attention to it. She never cared about it. She had no idea that it was influencing anything. Most people are realizing, “Food is something that had an impact. I couldn’t smell the gas,” if that had happened with the smoke, but it affected everything.

She was the poster child for me at that moment. I felt then I had to get the word out to have people recognize the gift that they have. They have a sense of smell to stop, smell the roses, and appreciate it because she is newly married. She felt like she couldn’t be intimate with her husband anymore. She had wanted children. She felt like she couldn’t be a good mother because she couldn’t bond with her child.

She wouldn’t be able to smell her child and worried that she was going to burn the house down if she was baking cookies and wouldn’t be able to smell them. Her sense of being able to be out in the world, she started to get paranoid about her odor and her sense of socializing. She felt like she couldn’t connect with other people, so she started to become more reclusive. She had a high-level analytical job.

Because of where in the brain smell is processed, it’s involved in our spatial memory learning analysis capabilities. Those sorts of things start faltering when you don’t have information on your sense of smell at the neuroanatomical mechanics level. The same thing with emotion. She was going into a spiraling, ever-worsening depression. It was everything about her life. This is what happens to people, not necessarily 100% of all the factors and not for everybody who’s lost their sense of smell, but variations of the disconnect that people experience in their life with other people and even themselves.

It is emotionally deafening or they can’t get the vibrancy that they had before. Their experience of a whole variety of walking outside, smelling like fall, or whatever the case might be. All those kinds of things are gone when people lose their sense of smell. It has become a serious issue because of COVID. First of all, especially in the first variance, loss of smell is a great symptom indicator that you have COVID. We did a study that showed that loss of smell preceded showing a positive PCR test for COVID in the first version of it by two whole days. It was an incredible diagnostic having this smell loss.

For most people, it was transient that they got their sense of smell back. Dozens of millions of people worldwide still have long-term long COVID version, with smell loss being the critical symptom that has been maintained. I have great hope. There’s real optimism for the future in terms of medicine in and of itself. First of all, there’s a possibility that they will get their sense of smell back naturally and there are things they can do from the comfort of their homes, like smell exercises, literally sniffing deliberately, and so forth. Doing that a lot can help bring back the sense of smell.

In coming down the pipeline in the pharmaceutical, neurological, and world of medicine, there are going to be real treatments for people who have smell loss. I’m optimistic that those people will get solutions and get their sense of smell back in the not-too-distant future, but this is because many people experience, even if it was transient, what life is like without a sense of smell. It did increase appreciation and awareness of this sense.

I did a study that data was collected in the spring of 2021. It was still at the height of COVID and things like that. We had two groups of the population as it were, so participants. One was college students. I had 200 or so college students, and then we had another group of 200 and 40-somethings and looked at how they valued their sense of smell relative to the other senses and compared to various common commodities.

We didn’t compare the other senses in that particular study. Subsequently, we’ve gone on to replicate this. We have it in seven different languages across the globe and thousands of data points now getting very similar findings, but in any case, right then and there, what we found is that sense of smell ranked way down compared to vision and hearing. Vision and hearing ranked similarly. This was the headline finding, 25% of college students would rather give up their sense of smell than their cell phone. Nearly 50% of women would rather give up their sense of smell than their hair.

One of the things that I’ve said is it would have been interesting if we had done this study in 2015 to compare it to the data that we collected from 2021. Maybe in 2015, 50% of college students would have given up their sense of smell for their cell phones. As this study is done again and again, I’m hoping that we see a shift further in favor of the sense of smell. In any case, it’s still a real indictment for people not recognizing the importance of smell.

This whole show is about giving people an optimistic view of the future. That’s something that I see in my own family members, their addiction to their cell phones. I hope that it’s a good thing. I do like face-to-face interaction more now that I have this digital presence. I value it more. I hope that in the same way that these other things have come up, maybe we’ll value our sense of smell more because there are other things that provide a significant distinction between an in-person interaction. That’s not something you can replicate. You can replicate vision or audio like we’re talking, but you can’t do the sense of smell.

FSP - DFY | Smell And Taste


It’s a different scenario, but I wanted to talk with you more about the taste and oral connection because that’s one of my areas of focus. Certainly, when I reconstruct somebody, and they lose half of their mandible or something like that, their quality of life plummets. They still have their sense of taste but the ability to chew and make those volatile particles that hit the back of the throat that proceed with smell receptors. They’re not able to do that. When we’re talking about the oral and taste connection, that that’s a significant thing, but that’s coming from my perspective. What is your perspective on it?

It’s interesting to me that you’ve shared this as I had no idea that chewing was now going to be impaired for people who’ve had this lower mandible surgery or if they have a loss at that bone. It made complete sense. It is a problem. One of the things that I would maybe say is that spending more time and using the correct terms, orthonasally sniffing while eating would be helpful for those people. For instance, the food is in front of them. They can smell it if it’s in front of them because their sense of smell still works so they can sniff the creamy potatoes and the charred or grilled whatever it is that they’re eating.

They can spend more time, maybe deliberately sniffing. Once the food is in their mouth, they aren’t able to do as much chewing, but then that brings up a question I have, “Does that mean those people have to have soft foods only and a liquid diet?” In a way, what I said wouldn’t be so much of a solution. I would still say even if it were liquid and liquids at least were things that they liked, then spending more time sniffing the liquids to get some of that pleasure from what they wrap those liquids represent. I don’t know if they’re savory ones as well. Hopefully, there are sweet ones and so forth.

To spend a little bit more time being present with the aroma that they’re sniffing even though they’re not able to get them much. It is the case that we do get retronasal olfaction from beverages. It’s not as strong because the time in the mouth is much faster. Typically, we take a sip and we swallow pretty quickly. We get less, but drinking wine, other things, even coffee, or hot chocolate, you are getting the retronasal and the aroma from the mouth.

One of the things might also be to keep whatever food is in your mouth a little bit longer before swallowing or being a little bit like not chugging things back, not just drinking the food for the nutrition and of itself, and not paying any attention to anything else. Maybe spend a little bit more time with the drink so that you can appreciate the flavors that are in it a little bit more and maybe get some pleasure out of it. I can see that probably in situations like this, not only are the food’s liquid, but they’re probably not that variable.

You have pretty much a lot of the same thing over and over again. That in and of itself creates pleasure as it were with whatever we’re consuming. There’s something quite well-known called sensory-specific satiety, which is related to food and it is not the same thing that can happen with beverages, but eating the same thing over and over again, you satiate on the sensory aspect of it and you lose the pleasure from the sensation.

This happens to all of us all the time. I use chocolate because I love chocolate. You get a fantastic piece of chocolate cake. You take the 1st bite, “It’s amazing,” 2nd, 3rd, 4th, or maybe by the 5th bite, though it’s lost, it’s fantastic. That’s because you’re satiating on the sensory characteristics, the aroma of chocolate, the sweet taste, and the creamy feel. You’re physiologically adapted to it so it is less intense.

Especially, if diets are very consistent because of being forced to only have a pretty small or narrow repertoire of what you can consume, I can see that that would be quite problematic. What ends up happening when people have very monotonous diets is they end up typically not eating enough, losing weight, or not getting enough nutrition because the food is monotonous. I can see that would be a problem for patients who were forced into a liquid diet and didn’t have the opportunity for that variety that keeps the engagement going with the food that they’re eating.

When people have very monotonous diets, they end up typically not eating enough, losing weight or not getting enough nutrition.

The function of chewing, I feel like, is something similar to smell that has been underrepresented in health literacy. The reason is that I can make someone look normal, but if they don’t have the ability to chew, they come to me and complain about how terrible their life is. If I can make someone look okay, but I can give them the function to chew and enjoy your food, very few complaints. That’s something I’ve noticed in my practice.

So much of our identity as humans is wrapped up in food. In this Neurogastronomy book, he was saying that the evolution of smell was different for humans and other animals. Some people describe one of the distinctions as that our pleasure for food grew our brain capacities so much so that now we are where we are. I see it daily when my patients come into me and the ones that aren’t able to chew, they’re not able to enjoy food because a certain amount of texture and the way it fits in your mouth is part of the taste overall flavors sensation.

For people who have lost their sense of smell, some things that help make food more pleasurable is having things with variable texture. Crunchy, creamy, and like a grape that’s popping in your mouth at the same time. Getting a lot of dynamics from texture can help people who have smell loss try to experience the pleasure of food again, but something that I write about in Why You Eat is the fact that humans are unique in having this open airway between their mouth and their nose which gives us the ability to experience flavor.

Humans actually are unique in having this open airway between their mouth and their nose, which gives us the ability to experience flavor.

Even animals that have exquisite senses of smell. For instance, your dog. You may drop a piece of bacon on the floor. They’re at it in the nanosecond, but all they’ve experienced in their mouth is the saltiness. They have smelled the bacon aroma before they get to it, but then in their mouth, it’s the saltiness. Unlike us, we get the full aromatics of it while we’re eating. The fact that we have this open-airway system is how we are also able to have language.

The complexities of what we are able to do with speech and create sounds that are intelligible and all the different meanings of language across the globe have to do with having this open airway system and the risk of having this open airway system with eating is choking. Other animals do not have to worry about choking while they’re eating because of the fact that they’re talking at the same time. For instance, inhaling why you have food in your mouth can end up lodging a piece of food in your windpipe then with the opportunity of potentially choking.

Whereas if you don’t have this open airway system, then that’s not a risk, but evolutionarily speaking the benefits of language for humans outweighed the risk of choking while talking anything at the same time, which is why if you learn when you were a kid, “Don’t talk with your mouth full.” That is not just for the manners of the table but to keep you alive because if you’re eating and talking with your mouth full, then you have a good chance of choking. This is what gives humans the unique ability to experience flavor and have language.

Honestly, this was interesting, and I wish I could talk to you for more. Before we get into our last three questions, I feel like a lot of what you were saying was descriptive. I’ve learned a lot from talking to you. If you could give me a proscriptive talk about how I make my patients healthier through their sensation of flavor, taste, and smell, what would you say to that? I know that’s part of the research that you’re doing as well. It is more of a holistic interpretation of food so that we can have better health outcomes.

Understanding all the things that go into our experience of eating and not to mention my book Why You Eat but all those things that we don’t pay attention to understanding no how it is that the person you’re with, the mood that you’re in, the environment, the colors around you and the way things look. All those things are interacting with your experience with food. I don’t like the term mindfulness. It’s overused and abused as well.

If we could be mindful in the moment, it’s paying attention to our experience with eating, then we get so much more out of it. We get so much more intense flavor. It will taste stronger when you’re paying attention to it than if you’re not. I’m sure that your readers have had the experience of having a bowl of potato chips, candies, or something beside your computer or in front of you while you’re watching TV or whatever and you are eating away. All of a sudden, you notice that A) The bowl is empty and B) You didn’t even get any of the goodness like, “I was looking forward to eating those chips and what? I already ate them. No way. It’s not possible.”

We pay attention to the food that we’re consuming, we get much more hedonic pleasure from consuming it. We get more satiated. That is to say, we feel more full because we’ve engaged with eating it. We go, “I did eat that bowl. It is empty for a reason. I got you know real pleasure from it.” We are much more in the moment, which is a good thing in any case. It’s important as a basic principle for health in general and eating not to eat while doing other things, especially with screens.

It’s good to eat with other people. It is also the case that the more people we eat with, the more we tend to eat and the less we are aware of what we’re eating. Thanksgiving is coming up. It’s a time when we all eat a great deal for several reasons. There is so much variety. The more variety there is the more we’re going to consume and it relates to that sensory-specific society that I mentioned before.

“I finished with the Cranberries now, I’ve got this sweet potatoes and then I have the baked potatoes and I move on to the stuffing,” and all these different things that we have room for because it’s different. That’s awesome in the case that we’re eating with a lot of people, usually a lot more than we usually eat with.

The conversation and the distraction of being with those people also take us away from what it feels like to eat whatever it is, “I’m getting some pleasure from this. I’m getting the specific flavors, the nuances, and everything else.” It is good to have food as part of our social existence and it is so much part of our social existence, it’s also important to pay attention to the sensory, emotional, hedonic, and holistic experience of what it is that we’re consuming to get the most out of it and to have a healthier experience with that.

FSP - DFY | Smell And Taste

Speaking of Thanksgiving, do you think it’s because there are many options? I feel like when I go to Thanksgiving, I want to try a little bit of everything, which makes me end up eating more. Is that the case or is it more so that you’re with around a lot of people? What would you say is the reason behind that?

The number one reason is the variety. The other people being there is a contributing factor, but Thanksgiving is like the all-you-can-eat buffet. If you ever go to a restaurant which hasn’t have an all-you-can-eat buffet, you could be there by yourself. The same thing happens. It’s like, “I’ll have a little bit of this. I’ll have a try a little bit of that.” You want to try everything. The fact that everything tastes at least a little bit different means that you’re going to eat at least some of it before you move on to the next thing and often, we eat all of it.

We often go back for more. One of the things I talked about in Why You Eat is that if you want to resist going back for seconds or thirds at an all-you-can-eat buffet, sit as far away from the buffet display as possible because humans are reasonably lazy. If we don’t see it and it’s not an arm’s length away, we’re less likely to get up and go get more. On Thanksgiving, you don’t have to move anymore. Typically, it’s right there on the table. It’s easy to say, “I’ll have another scoop of those mashed potatoes. You’re passing the stuffing around again. Sure, I’ll have another.” That’s one of the problems with Thanksgiving.

That’s a very timely way to leave this program. Before we go to the end of our show, we’re going to talk to you a little bit about the three questions that we ask all of our guests. One is what do you gain inspiration from? When you went down this path of deciding to spread the word about smell and taste, for me, when I do this show, science fiction is something that I gain inspiration from. I want to have that utopian view of the future that is available and that many different science fiction outlets, but for you, what is it that you look towards for your inspiration?

Sharing and talking with other people gives me a lot of inspiration and energy. When I talk to other scientists, what’s happening now in the field of smell is incredible. We are on the fastest-rising trajectory both in medicine and technology than we’ve ever been before. What’s coming is exciting. I’m inspired by that. I’m very inspired by my dog, who’s spent a lot of her time sniffing. I look at her and think, “She’s taking in the moment. She’s learning things.” She’s on her social media apps as we’re taking walks, sniffing, and various places. That’s inspiring to me.

At another level where I get my downtime thinking, I love mysteries. From a reading perspective, I’m all about reading and listening to mysteries because I spend a lot of time outside walking my dog, looking at her, sniffing, and then listening to books. That’s probably part of it. I try to also pay attention to my own experience as much as I can, like, “What was that that I had?” I get inspiration and gratification when I see the light bulb go off in someone else and they go, “Smell is important. I never realized that,” and I do get that with teaching with students and that’s extremely rewarding and gratifying.

One of the things that you hinted at was that there are some breakthroughs coming down the pipeline for smell and taste. What are the ones that you’re most excited about?

There’s a lot I’m excited about. I’ve already mentioned that in medicine and therapeutics, there are things that are going to change the world for people who have lost a sense of smell. You mentioned that, with screens and everything, we don’t have that sensory dimension, but that’s going to be changing very soon as well. In coming to smartphones, tablet, or laptop in the near future, you are going to be able to have a small add-on or piece of hardware that will enable you to smell, create different smell,s and share smells.

For example, you and I were separated by the screen. You said you’re in New York. I’m in Rhode Island. Behind you is the universe. If you and I, for instance, both had a scent cartridge on our tablets or laptops, and we tuned it to the same scent, you would be and I would be experiencing the same smell. Even though we have different noses, we would be sharing that scent experience in real time.

That would give us another level of connection. It breaks this fourth wall of the screen between us in a very visceral and emotional way. That’s completely different than what we’re sharing even though we have two senses. This third one will be so much more emotional and visceral because that is what distinguishes the sense of smell from everything else. It will give us a level of interconnectedness that we probably don’t realize which is extremely intense and would change a lot.

Last question, where do you see us in ten years? Do you see us as a species having more focus on smell, maybe having a better sense of taste? I’d love to know your thoughts on what you see coming down the pipeline for us.

Utopian only, then what I talked about with respect to technology, science, and medicine will enable, first of all, more people to smell. One of the other things that’s critical is as we get older, our sense of smell, like with vision and hearing, tends to get worse. Along with it, there’s an extremely important interaction between our ability to smell and our cognitive capabilities. Keeping our sense of smell healthy as we get older, and as the population is aging, will keep us smarter, more mentally active, and also be important for our physical health.

There’s an extremely important interaction between our ability to smell and our cognitive capabilities. Keeping our sense of smell healthy as we get older and as the population ages will actually keep us smarter and more mentally active.

Being able to smell has tremendous spillover into both our mental, neurological, and physical health. The technology and therapies that are being developed will enable that. That’s something that I’m excited about. The fact that our technologies will have smell as part of them, even though we may be separated by computers, will still going to be a lot more connected than we are now because the census will give us this interconnectedness that will change things in a positive way.

I like that utopian vision. I look at it as that now, more than ever, people are focusing on what they’re eating, tasting, and smelling. That produced good results. The food that I had now was better than the food that was available to me many years ago. I feel like there’s a new focus on better ingredients, health, and a whole wellness industry that didn’t exist many years ago. I appreciate that. A lot of it has to do with people understanding themselves and how we operate better. Thank you so much for joining us. To all of our readers, please like and subscribe. We will see you again in the future. Thanks, everybody. Have a good day.

Thank you.

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About Rachel Herz

FSP - DFY | Smell And TasteRachel Herz, PhD is a neuroscientist and world leading expert on the psychological science of smell. She has been actively conducting research on the senses, emotion, perception, motivated behavior and cognition since 1990. Dr. Herz is a TED speaker, has published 100 original research articles to date, and has received numerous awards and grants. She is on the faculty at Brown University, a professional consultant to various aromachemical industries, and is frequently called upon as an expert witness in legal cases involving the sense of smell.

Dr. Herz is also actively involved in outreach, advocacy, and education on the senses of smell and flavor, and is a founding advisory board member of Fifth Sense, and Smell and Taste Association of North America, Innovation Advisor to The World Taste and Smell Association, Chair of the Strategic Planning Committee for AChemS, and the Chief Scientific Advisor for OVR Technology. Additionally, Dr Herz is the author of a number of academic and popular science books including: the leading college textbook on Sensation & Perception; The Scent of Desire: Discovering Our Enigmatic Sense of Smell (2007; Harper Collins), which was selected as a finalist for the “2009 AAAS Prize for Excellence in Science Books”; That’s Disgusting: Unraveling the Mysteries of Repulsion (2012; W.W. Norton & Co), a New York Times Book Review “Editor’s Choice”; and Why You Eat What You Eat: The Science Behind Our Relationship with Food (2018; W.W. Norton & Co), which was a finalist for the “2018 Readable Feast Awards” and ranked among the “Best Food Books of 2018” by The Smithsonian and The New Yorker.


By: The Futurist Society