Taste Matters: Why We Like the Food We Do | Professor John Prescott

[00:00:10]yeah so having in Gales here we lost mayor's ball in a coma seen as having sale girls here for EVS a Hindi again dr. John Prescott and some us they did to e confirms was imposing or DC super days and food or other side then my goodness t even they stand goal is to profess Prescott hand in to send Bellhorn and would end in for expansion Tsubaki prasanna mango a pipe of killing still shown of angeas Harlan our new zealand of seems the Italian infoset so students gabar Tsubaki of reviving scape another lecture it at him in silence college is closed on forever well well answer or hangout for ferreting bowls America interfere knock some de it already children that taste matters taste matters why we like the food we do I hope it'll be all set to dance so John I'm giving a commercial for your book in very look while I'm introducing you and I do hope that you'll succeed to get this translated into danish it's a book that is really worth while reading and it's a wonderful read it easy read and it's i think is going to be and already is a very important book so be very fortunate to have them John with us today and he is going to tell us about why we like the food we do it's it's a great pleasure and a great honor to be invited you to give a talk at this opening of the center it's not for the first time that the rest of world looks at den markets as well what a sensible thing they're doing and I think cultural and scientific spheres and and you can look at a center for tastes like this and realize that that it's going to be an extremely important center for helping us understand not just I guess basic sciences but the application of their sciences to real world problems like the health of you and your children and so on says it's very impressive and as I say a great honor now I thought I would start off my talk today by it with a quote from well-known Danish royalty Anna and I and I put that quote up because it gives you one example of where we use the word taste in our everyday language or at least when I say we Shakespeare use the word taste and I can't promise you a passionate speech but what I'm going to try and do is to show you in fact I'm an academic so I study taste okay and associated sensors and how food preferences are formed but I'd like to show you that in fact you all know quite a lot about taste already from your your language and I'm going to show you some science but it will show how it relates back to our everyday language and our everyday understandings of taste which not only not at odds with the science but are often a reflection of it so I first went to the Oxford English Dictionary largely because I've got one and you've got to use it you know because it's so thick and inexpensive and and I came up you know really i'm going to go through these each in turn so you'll see these come up again but we've got sort of five main definitions of taste they're tasted all sorts of things and depending on who you ask what what is taste well it's the ability to show good judgment in purchasing furniture is tastes really well how does that relate to you know the stuff that we put in our mouths um I'm hoping to show you exactly how those those sorts of things are linked taste is in fact embedded in our language and I'm hoping that damage is not too different from English I think English borrowed one or two things from Denmark or maybe English gave you everything I'm not sure I can't one way or another but certainly in English we see a lot of fors probably their metaphors for all sorts of emotional experiences and qualities and you don't see this with other any other sensory system there's something about the sense of taste which seems to be related to emotions seems to be related to evaluations so in particular sweetness in English we talk about the sweet smell of success we talk about victory being sweet we talk about a sweet spot so when Roger Federer you know hits book a winner you know the ball has come off the sweet spot of his racket we talk about sweetness as a metaphor for pleasure so we talk about sweet soul music and there's lots of other examples i could give you or desire we call our loved ones sweetheart or my sweet and we use the word sweet to help us overcome some initial fears and poor reactions so that you know if you're a little bit worried about eating awful that the idea was by somebody or other that would be a terrific idea to call them sweet breads and maybe you'll eat them negative emotions too are built into the language and and and and access our knowledge of sweetness so we talk about people becoming embittered by by failure or by loss we talk about bitterness in terms of disappointment and distaste and hatefulness and resentment or sourness people have a sour face and then they're discontented in some way or ill-tempered and we express that in terms of a taste so there's lots of examples but I'm giving you just a few here and i'm going to show you that these these metaphors come out of really what taste is all about so let's let's start off what is taste well our first definition from the oxford english dictionary says it's the action of tasting or perceiving of flavor or the sensation in the tongue or other organ by contact with a soluble substances pretty dull okay I've underlined in the tongue because the sensations don't happen actually in the town or the I they happen in the brain so I I was just correcting them there but when we talk about the taste from an academic point of view the gust the gustatory system we recognize that it has a few small qualities a small number of qualities sweet sour salty bitter have been talked about for at least 2,000 years and stomach Aristotle more recently we talked about a fifth taste called umami which in english language actually has a reasonable translation of savory and i'm sure there's something in the danish language as well we recognize possibly fat people are talking about the taste of fat as being of a primary taste now if you wanted to describe an apple you're going to have trouble if you only use those tastes okay because we know it's sweet and it's our it's not salty it's not could be bitter i guess not really very much amami not very savory not very fatty so in other words a complete description of an apple is something which is salty which is sour and sweet and clearly that's not true if you want to describe this is what people in sensory about food center evaluation do they describe things like apples in terms of stewed flavor and honey flavor and flour innocent grassy over and so on and I show you this example simply because this idea of taste actually from the dictionary is really to say that that we don't perceive tastes alone in food what we perceive in food is flavors okay and flavors include taste they always include Tate but there's something more so in other words we often talk about the taste of an apple but actually what you mean by that is a flavor and you're quite right because flavors are really what foods are all about and they include taste but they also include odors often they include tactile sensations from the mouth some people would say that they include sights and sounds I wouldn't but some people say that but what we need to understand is the brain assembles it takes information from the taste system and from the olfactory system our sense of smell and assembles flavors into the brain and you can actually even identify using brain scanning techniques where a flavor is located and it's not the same as places to taste and it's not the same place as an odor it's a unique sense and in fact if you go back as I say at the bottom there you can you can actually that the whole idea of flavors is actually very old this is a 17th century definition that flavor is a quality perceived by taste aided by smell nowadays would say smell is a very very big part of it and that as I say is consistent with our everyday thinking the important thing for you to know about this is that and and if you're not in the signs you may not know about things like this got the pointer I don't know that I do Arthur thank you so in fact when we perceiving flavors it's not a very clear slide I'm sorry but but you know the odors and the taste our piece of Apple goes in the mouth there and is chewed and the the tongue is responsible for tastes of course you know that but the the volatile chemicals from the Apple go through the back of the mouth and reach the the smell receptors the same smell receptors when we're sniffing but if this is a different way of getting to them and that combination in of the taste and the smell in the same place leads us to perceive flavors and leads as I say there to development of preference which I'll be getting on to now there are some very obvious examples and I won't dwell on this too much obvious examples of of the consequence of combining tastes and odors together and I guess it's true in Danish as it is in England English if you smell something like strawberries or caramel or vanilla the most common word in English we would use is to say that smells sweet and the reason that's happened is because the brain is combining the taste and the smell together okay and it doesn't really distinguish it's all about the flavor of the strawberry and likewise for a lemon or for vinegar you say smell sour and that's because in the past these smells the odors and the tastes have always been experienced together and that's why vanilla always smell sweet because you never experienced vanilla and salty well you might in the Nordic food lab or at nomura somewhere but in the real world you don't and and this has been well known i mean the the the the french sort of philosopher of taste jean health umbrella sovereign it's a wonderful book called the physiology of taste it's not about physiology at all but he sort of musings and meditations about taste and he said in 1825 i am tempted to believe that smell and taste are in fact but a single sense whose laboratory is the mouth and whose chimney is the nose and in science to now we think about the flavor sense alright so that's one sense in which we we think about taste the next one is another definition there's a blend of two words tangere and Gus gastar a so touch and taste okay that's where the word taste comes from well isn't touch sip separate from taste what do you of course you can say that you don't have to use the taste system but I put these little babies photographs to show you and anybody's ever had any dealings with a young baby will know that one of the one of the things they do is they spend their time exploring the world through their mouth and the reason is because there's much more they're up it's much more heavily innovated with receptors in the tongue and the lips than it is in the hand it's a better place to explore the world with you've got more nerve cells there and so we think about the tongue as a as a place where we we manipulate food and we also you know experience taste on there but in fact the tongue if you cut it open don't try it at home you'd find that there are lots and lots of receptors and nerves that to do with the sense of touch and the sense of temperature and so on then there are actual taste nerves and if we look here at the this is a surface of the tongue which has been stained and what sits up here are these little structures and they contain the taste buds and you can look at those in the privacy of erin hamlin tonight if you like in the mirror but but they contain not only the taste buds but they contain the fibers that that to do with a touch when we have a nice curry and we find it very very hot it's these these these fibers from this system it's called the trigeminal system that are actually being stimulated not our taste buds but actually they're in the same structures here so in fact this is absolutely correct that that really it's almost impossible to taste without touching and the two are completely interlinked and so the the baby is a reflection of what the baby is doing is exploring the world through the sense of touch and will later come to explore the worlds for the sense of taste a next definition is of taste and yet more yet more Shakespeare here an old-fashioned definition perhaps but but very very accurate what is taste it's a test or an examination and leah says he wrote this but as a test of my virtue he was testing my virtue by writing something okay a taste of my virgin but he meant a test well that's extremely accurate our taste sense is large our responses to taste anyway are largely in eat it's the only sensory system that's true of weed not born liking the color blue okay or the sound of a violin or anything it is only in the taste system that we're born with inbuilt likes and dislikes we're born liking sweet tastes and you can see that's a little baby that's never been fed this hasn't received any feeding from its mother and scientists was allowed in to do his dirty work and gave the baby some sugar on the tongue and what does it do licks its lips what does a rat do licks it slips on the other hand you put a bit of quinn een that's the sort of bitter substance in tonic water and what does the baby do it does it say exactly the same as you or I would do if we found it too bitter and what does the rat do exactly the same and you can show that with a lot of mammalian species our taste preferences are innate and they're also interestingly and I'll come back to this later either interestingly the earliest sources of pleasure pleasure and pain that we experience as humans and I'm going to try and make a case for why that's important later cross culture you can you can show that tastes are or at least provide evidence that tastes are all our response to taste their independent of diet so here's three groups Australians and Japanese and Chinese very different diets but yet when you give them some these are increasing concentrations of sweet taste and a bitter taste of caffeine and when you ask them how much they like them you get exactly the same patterns across three cultures with vastly different dietary experiences so this suggested something in native about taste well if you've if you are born with a fixed response to something that the only question to ask is why is that what what's happening what's the advantage of that in other words from in evolutionary terms and we sort of think that we know we've evolved to respond to basic tastes because of their survival value and this is why the taste system itself actually acts as a test because it's a test of nutrients and toxins that's exactly what our taste system is doing its testing for the presence of nutrients and toxins so in the case of sweet we know that the only mammals that respond to sweet substances by and large are the ones that eat plants and they get carbohydrates from plants cats are indifferent to sweet tastes whereas we quite like them dogs like them and so on and if if you're at all inclined to eat plants in your evolutionary history then you sense taste and you'd like it because it's a signal for calories sourness is typically disliked particularly at higher levels and we think that as a signal for ripeness rightness spoilage and clearly when fruit is unripe or fruit is overripe it's much more sour and so it's a signal telling us at what point we should be eating food saltiness which is light of course it's very easy to explain because if you don't take it's the only mineral if you don't take into in your diet you will die and you will die very quickly and so it makes norma's evolutionary sense well bitterness if we're in the forest if our ancestral in the forest and came was hungry and came across something that was bitter that almost inevitably they would have rejected it now it's not an absolute test but it's a good signal if something is bitter than actually might be poisonous umami this fifth taste well in certainly in foods it's highly light that's one of the reasons why we add all sorts of things like tomatoes mushrooms palmer's and cheese to our dishes because we're we're throwing in amami we're not quite sure about this but the preeminent explanation is that it's telling us about the presence of amino acids or proteins again which are important to take in the diet and fat if it is a taste and we're not quite sure again is a bit like sucrose in that fat is a tremendously high source of energy which will help us survive so that's what I taste the sims earrings testing its environment testing the foods testing things that comes across to see if any of these things are present another definition is a small portion or a sip of a food or drink to be tasted as a sample it's a bit likely what the royalty used to do in medieval Europe they'd have a taster to see if something was poisoned it's an experiment as it's trying to work out whether something is good or bad before you actually take in the whole lot and the taste system is exactly like that now I'm going to illustrate that point by looking at some of the things that stop us from eating and I hope that would become clear it looks like on the surface of it you know if you look at the things that we eat cross-culturally it looks like we eat anything okay so here's two examples from one from Iceland and and one from Finland I've gone all you know Scandinavian on you but you could pick examples from anywhere I particularly like this because it's a couple of quotes see the Anthony Bourdain who's a famous American chef the single worst most disgusting and terrible tasting thing he's ever eaten Gordon Ramsay and you can look this up on YouTube and I suggest you put in the word her car and Gordon Ramsay and he tastes it I he doesn't say bloody hell he says something else ok but it's the same sort of exclamation of surprise and shock and then he asks some of you quickly get a bucket and the vomits so it's nice but the Icelandic people love it apparently and of course we've got this finished licorice which I haven't tried but it doesn't sound particularly pleasant and yet the fins adore it it just shows you what the fins are like so it looks like we can almost eat anything but in fact there's lots of things that stop us you know there's lots of things we take advantage of that the taste system broadly including our eyes our sensors generally to tell us whether something is likely to be okay to take in and one criterion that we use that's very very important is if we can't predict the taste of something then we tend to reject it out of hand and I've got two examples here the one on the left is you got that sort of pink colored now if you were given that and you were told that that was a smoked salmon mousse and it was then you think I was very nice if you were given that and you were told it was ice cream and it still tasted like smoked salmon it's still the same substance but in fact it's likely that the surprise you experience would lead you to reject it and that's exactly what my colleague Martin Yeomans in collaboration with the chef heston blumenthal showed that his rated pleasantness and he was the food label when it was labeled ice cream versus when it was labeled savory mousse or just something neutral that you can see there when it's labeled ice cream it was chilled and so on people rejected it they found it very very unpleasant despite the fact that that the flavor was exactly the same so that's a key thing that if our expectations aren't met it's possibly a signal of danger of unfamiliarity unpredictability and that's a problem okay we want the familiar here's another example on the right hand side and this was done by the guardian newspaper sometime late last year where they took some pringles new flavor of Pringles crisps around in a shopping centre and filmed them and and as it will taste this and they film people's expression it's a potato crisp right but this one's clearly showing absolute disgust at that and why well the answer is that the flavor was chocolate mint now it's not the chocolate mints a terrible flavor it's not the chocolate mint per se says god this could be you know it could be dangerous but it's the unpredictability which is is is a problem to our brains we don't like that in fact one man in this film clip said actually chocolates my favorite flavor but he still had that same expression when when in the context of a crisp so the context is is almost everything well as I said a moment ago it looks like we eat almost everything but in fact that's simply not true we can eat almost everything but we're presented with a thing called The Omnivore's Dilemma and we're very lucky just like rats that we can eat meat some mechanic plants and you know things that the Nordic food lab throws at you you can eat probably in the wild you can eat almost anything but almost anything is almost certainly going to include things which are toxic that could poison you so it's a great advantage and one the one hand great lots of sources of food but on the other hand also increases your source of potential danger by contrast an animal like this when we could include other animals we can include the koala we can include the panda animals that only one thing never worry about it and have an omnivores dilemma you know blood is never going to poison them that's all they eat so they but they're limited if blood isn't available they die so they're very limited so it's a trade off and on the whole I'd rather be an omnivore now this dilemma has one consequence and that is that we develop a thing called food neophobia now anybody who's ever had small children probably knows a lot about food neophobia and it's characterized by children typically standing about the age of two give or take where a child will say oh I don't like that but you've never tried it no but I don't like it and what they're saying to you is I don't like it because I've never tried it these two things aren't a coincidence they're saying I'm not eating that because I've never tried it and the mother will always say well come on you know you please just give it a try no no it's a problem and the reason is is that this developmental stage that children go through is a way of protecting themselves again think about our evolutionary history in the wild about two years old would be the time that humans started to wander away they can now walk you can now wander away from your parents and you can now come into contact with things which again potentially dangerous and so how do you deal with that you become very very very conservative about what you what you is that 15 minutes did you say okay okay you very become very very conservative in your in what you eat and that helps you survive now of course some people adults still have high levels of food neophobia and but the important thing to note is that the fear of taste fear of a bad taste is the mechanism and in you know as a corollary the remedy is actually creating expectations of a good taste we can also look at the omnivores dilemma in terms of how cultures are actually deal with it so if you're in a culture and your food supply changes what's to prevent you from rejecting foods which are now novel and and you know possibly dangerous you don't know well so cultures develop these things called flavor principles and they help us to make things familiar so if you're in Vietnam and you normally eat chicken and your chicken is not available you have to eat pork which you've never had how do you stop people rejecting it well you cook it in fish sauce lemon grass and coconut and become instantly part of your culture it's you it's a Vietnamese dish shrimp from then on and so these flavor principles are the way of not an air culture expressing itself but actually of maintaining a flexibility in sources of protein particularly that come into the society so well the other thing which is particularly a taste related emotion is this idea of disgust and again that's a motion which is helping us here you see two people a tribesman modern-day tribesman who's at very little contact with the west from New Guinea and somebody from the 19th century expressing the same emotion we don't know it what in the case of this gentleman but he's just been told to imagine that he's seen a dead pig in the road that's been lying there for a week in the hot Sun and he's disgusted by it now why why do we have that emotion well the thinking is really that it's helping us to avoid foods we're testing food helping us to avoid them because they might contaminate us so its inbuilt disease avoidance mechanism now from the point of view of this band-aid on the pizza or the rotting role there that you think well that's fair enough you know you wouldn't want to eat that but think about the problem you have in some of the issues that the New Nordic food lab is is dealing with is how do you get people to eat something like insects chopsticks or now I'm not eating a grasshopper I'm going to have to go very quickly because I've given been given such a short time by out by our Chairman unreasonably the but I'm going to go quickly because I just want to talk about the mechanisms of how taste preferences developed and I'll go through these quite quickly well there are three main mechanism where do our preferences actually come from well the first one is very simple just exposure but the important thing to know the practical thing to know is the exposure starts prior to birth in utero and the interesting thing about it I just talked about flavor principles well how does it how does a culture maintain the same flavor principles and how does it passed on from generation to generation well the flavors this fetuses exposed to those in the mothers diet and what is the mother eating she's eating the foods of that culture and what happens to this child when she's born and later on is that the flavors the mother was exposed to become preferred so even at two years later you can show that the mothers diet while pregnant influences the the child so simple exposure is a very very important mechanism the next mechanism want to talk about is we like things when we pair them with something that's already liked now I'm going to skip a lot of detail here because of time constraints but for example soft drink manufacturers know that when you put lots of sugar in something we like sugar our bodies like it and the taste of sugar is very pleasant and we pair a weird flavor like the flavor of coca-cola with it we actually end up liking that flavor because it's been paired with something good and you can see an example here from an experiment where we just impairing an odor together with sucrose and you know in solution and the these odor becomes more liked now there again there are lots of examples not just these sorts of experimental examples but friggin what do important people do so pairing of somebody who is important with a food or a beverage pair it with adults with our peers with role models with celebrities of course that's what advertising does all the time something which is liked paid with something which is new somehow the positive aspect gets transferred over the items new and this these data here show simply that a child who is exposed to an adult role model cleaning a red drink at a selection of different colors will choose the red drink more often comfort foods what do we mean by that well the foods that help us feel better why what is what is all that because through associations once again so our chicken or our pastor and so on the flavor of that has been associated with something highly positive namely our family our friends our home our half our culture our country and the final mechanism and these all go together but we can distinguish them final mechanism really helps us explain why we tend to eat things which are bad for us and things like fat things like salt things like sugar and the answer is very simple if you remember the why we like salt and why we like sugar and why we like fat because the body wants them their source source of energy in the case of sugar and and and and fat and you can show that in fact when you pair a flavor with a nutrient that the body values in this cases its monosodium glutamate and the body values that that in fact this is a change in liking for a soup with which has been repeatedly paired it becomes very very liked how do we know that this is because the body values it well on the right hand side I'm showing that these pairings work very well when you're hungry and much less well when you're not hungry and if the if the pairing if you're pairing a flavor with aspartame for example instead of sucrose actually there's not much change because it doesn't provide the body with any energy ok I'll wrap it up now let's see what else you don't want to say well of course we can do the converse and that is we compare things with an unpleasant experience like Quinn Ian and produce dislikes but I I don't have time to go in that one final point i'd like to make because this is an important point to do with health and that's this when we pair a flavor with a nutrient something the body values we get to like it but the other thing that happens we now know is that that that flavor can induce hunger and in conduce increased intake in other words the body is telling us that the flavor is now signal for something we should be eating eat it now eat more of it and as a result what happens is that anything that's paired with something the body likes gets to be a signal for something we should eat I don't have time to go into that that study now but sorry I wanted to point out that simply sensory cues that are associated with ingested nutrients like fat like sugar come to induce what is now being called hedonic hunger and this is one reason why diets don't work at all because the diet says well we want you to reduce those things that the body craves namely things with fat with sugar in them things that give you pleasure I think that's a warning for me / 22 22 I think the bolt of lightning is coming next but the things that give you pleasure other things that we crave because we crave them hedonic lee we crave them for pleasure and if you don't think about the fact that people eat for pleasure you can't possibly understand how you can get the meat to eat healthier healthier diets leaves do not satisfy her Donna can go by the way I just thought I'd mention that look I'm going to I'm going to leave it there I think I'm over time I hope you found it interesting and if you'd like to ask me any questions I'd be happy to to answer them thank you I you