Taste
March 5, 2008
Category: Research • Taste
Any serious wine drinker will tell you she can distinguish between inexpensive, low-quality wine and the fancy premium-priced stuff. She may also claim the ability to discern the difference between wine made from different grapes, or produced in different regions of the world. Yet some studies have found that even so-called experts are unable to figure that "red wine" was actually a white wine dyed red, and nearly everyone seems to be swayed by the label on a wine bottle. Wouldn't we all just be better off if we simply kept an old empty bottle of fine vintage wine and refilled it as necessary with the cheapest boxed wine we could find?
Not necessarily. Ordinary individuals can be trained to tell the difference between wines along a number of different dimensions. One key aspect of the flavor of a wine is "mouth feel," which, as you might guess, describes the feeling of a wine inside of the mouth, before it is swallowed, and independent of smell. Can ordinary individuals be trained to discern wines solely based on mouth feel? Does everyone "feel" wine the same way?
Researchers have known for some time that not everyone has the same ability to detect tastes. Some people -- "super-tasters" -- are especially sensitive to a wide range of tastes. As it turns out, whether or not you're a super-taster may come down to your ability to detect a single molecule: 6-n-propylthiouracil, or PROP for short. Those who can taste PROP find it incredibly bitter, but super-tasters are also extra sensitive to saltiness, sweetness, and even tactile sensations in the mouth.
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Posted by Dave Munger at 2:53 PM • Comments (13)
January 15, 2008
Category: Development / Aging • Research • Taste
At least once or twice a week at dinnertime, our family has what we call a "harmony meal." Jim and Nora are good eaters with broad tastes, but they both (along with me and Greta) also have some foods they don't like. A harmony meal is a meal where everyone in the family likes every dish we serve. These aren't necessarily the healthiest meals (spaghetti with meat sauce and garlic bread is a favorite), but it's nice to have a meal where everyone's happy about what's being served.
When we're not having a harmony meal, we all still manage to find something we'll eat -- and our kids understand that if they don't want to eat dinner, then they'll just have to wait until breakfast. But everyone knows horror stories of kids that simply won't eat anything except for McDonalds' French fries, or Dad's macaroni and cheese, or Grandma's cookies, when their parents would really prefer chicken piccata with couscous and asparagus. Were these kids just raised badly? Or do they literally have different tastes than their parents?
It turns out that researching the relationship of parents' tastes with those of their kids is a difficult proposition. Some researchers have tried presenting families with lists of foods and asking them to rate how much they like and dislike each food. The parent's tastes might correlate with those of their kids (and they did, in several studies), but does that reflect parental influence on the child, or the larger influence of society on the entire family? And isn't any list of food by definition limited?
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Posted by Dave Munger at 3:00 PM • Comments (20)
December 19, 2007
Category: Face perception • Research • Taste
Do smells have an impact on how we judge people? Certainly if someone smells bad, we may have a negative impression of the person. But what if the smell is so subtle we don't consciously notice it? Research results have been mixed, with some studies actually reporting that we like people more when in the presence of undetectable amounts of bad-smelling stuff. How could that be?
A team led by Wen Li believes that the judges might have actually been able to detect the odor, and then accounted for it in their response -- giving a face the benefit of the doubt when there's a hint of bad odor.
But odor detection is a tricky thing. Sometimes you're not sure if your milk or wine has gone bad, even after giving it a good whiff. The researchers felt that controlling the odors for a study would be the key to getting good results.
They first determined the odor detection threshold for each of 39 student volunteers. This was done by having each person sniff bottles containing progressively stronger solutions of three different compounds: Citral ("lemon"), anisole ("ethereal"), and valeric acid ("sweat"). The threshold was determined by when they could detect the odor. Then, for the actual experiment, bottles that were about 100 times more dilute were used.
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Posted by Dave Munger at 5:00 PM • Comments (1)
November 14, 2007
Category: Research • Social • Taste
Both Greta and I are big wine fans. Despite Jonah's recent extremely popular post, I, at least, believe that I can tell the difference between good and bad wines. I'm still convinced that a good wine is more than just an attractive label (though I'm a sucker for labels with Zinfandel puns like "Zen of Zin" or "Amazin"). That said, the research suggesting that labeling has a lot to do with wine preference is also quite convincing.
Several studies suggest that we expect to prefer wines from certain vineyards or regions, and in many cases wine drinkers will actually rate the identical wine higher when it's presented in a fancier bottle. These results apply not only to wine, but to a variety of foods. Restaurateurs have known this for years, placing special emphasis on the presentation of the food in addition to the actual preparation and ingredients.
So if presentation matters, then perhaps the presentation of wine could actually affect the taste of the food it's served with. This is the premise of a study by Brian Wansink, Collin Payne, and Jill North.
In their first experiment they served 49 graduate students cheese and one of two types of wine as they arrived at a reception. The wine -- in both cases the identical cheap Cabernet -- was served in bottles labeled as being from California or North Dakota. Prior to drinking the wine, they rated its expected tastiness on a scale of 1 to 9. After sampling both wine and cheese, they rated both of them for actual taste. Here are the results:
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Posted by Dave Munger at 2:16 PM • Comments (6)
November 1, 2007
Category: Emotion • Perception • Research • Taste
This article was originally posted on May 10, 2006
Recent research suggests that one of the reasons that as many as 97 percent of women and 68 percent of men experience food cravings is because of visual representations of food. When we picture food in our minds, our desire for the food increases. So why not just distract the visual system? One research team attempted just that, tempting volunteers with pictures of chocolate, and then distracting them with either a randomly changing visual image or an auditory task. The participants who watched the visual image experienced fewer food cravings.
I've attempted to reproduce the type of display these researchers suggest may distract you from your cravings (click on the image to start the animation).
The original research, however, didn't take into account whether participants were hungry. Perhaps if you're already hungry, the visual distraction won't help.
Read on »
Posted by Dave Munger at 2:24 PM • Comments (8)
April 18, 2007
Category: Perception • Research • Taste
One "trick" dieters often use is to put their food on a smaller plate. The idea is to fool yourself into thinking you're eating more food than you really are. But doesn't our stomach tell us how full we are?
Actually, it doesn't. Brian Wansink has devoted his career to studying how perception of food intake relates to actual eating behavior. Together with James Painter and Jill North, he's come up with a dramatic demonstration of how wrong our stomachs can be.
Volunteers were recruited to participate in a soup-only lunch in a room adjoining the school cafeteria. They filled out a form asking about color preferences, then were seated a table with four different-colored bowls. The colors were just a distraction: the real purpose of the study was to see how much people would eat when their soup bowls refilled automatically.
Two of the participants ate from self-refilling bowls; the other two had their bowls refilled by a server. Everyone was encouraged to eat as much as they wanted. The self-refilling bowls involved a fair bit of cooking technology -- plastic tubes connected a soup pot next to the table to the underside of each bowl. The refill rate of the bowls was adjusted so that the bowls could be filled completely in 20 minutes -- the duration of the study. Technically the bowls could be nearly empty by the end of the session, but each bowl held 18 ounces of soup, so this would have required consuming over a quart of soup!
Despite the fact that everyone's bowls were refilled, the people eating from self-refilling bowls ate 73 percent more soup. Even more surprising is that they didn't feel any different from people who ate from manually-refilled bowls:
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Posted by Dave Munger at 2:00 PM • Comments (7)
November 2, 2006
Category: Development / Aging • Research • Taste
Conventional wisdom has it that giving young children chocolate will cause them to become fidgety. This belief is so pervasive that many parents won't give their kids candy within several hours of bedtime, convinced their children won't be able to sleep. After Halloween, many parents ration their kids' candy consumption, again based at least partly on the belief that too much candy will cause kids to go bonkers.
But when Michelle Ingram and Ronald Rapee became interested in the phenomenon, they were surprised to find that in fact very little research has been done on the effect of chocolate on children's behavior. While several studies have found very small behavioral effects of artificial flavoring and coloring, the limited research on sugar consumption has found no effects. Some studies have found that exposing children to large quantities of caffeine does affect behavior, but the amounts involved substantially exceed what is found in a typical candy bar.
Despite this lack of evidence, when Ingram and Rapee approached five preschools to ask them to participate in a study of the effects of chocolate on behavior, two schools turned them down because they were certain that the chocolate would adversely affect the kids. Nonetheless, they persisted, and the resulting study of 26 four-year-old preschoolers is the largest study of the effect of chocolate on children.
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Posted by Dave Munger at 4:10 PM • Comments (14)
October 11, 2006
Category: Research • Social • Taste
Cognitive Daily would not exist without chocolate. Every week, I buy a bag of chocolate covered raisins, and I portion them out precisely each day so that I've finished them by all by (casual) Friday. I try to time my consumption to coincide with the most difficult part of the job: reporting on peer-reviewed journal articles. The little news items, Ask a ScienceBlogger responses, and other miscellaneous announcements can be completed unassisted by chocolate, but then there wouldn't be much reason to visit the site. Sometimes even the chocolate raisins aren't enough, and I head for the nearest coffee shop for a cookie or other chocolate treat to further lubricate the writing apparatus.
While I can anecdotally say that chocolate helps me write, actual research on the impact of chocolate consumption tends to focus on negative effects: cravings, effects on weight, or tiredness. But Michael Macht and Dorothy Dettmer have partially rectified that problem with a simple little experiment on the emotional effects of chocolate consumption.
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Posted by Dave Munger at 3:53 PM • Comments (6)
October 3, 2006
Category: Research • Social • Taste
Tired of all the hoopla about the Blogger SAT Challenge? Do you not want to hear another word about Booker T. Washington and why he is or is not like George W. Bush? Then have I got a study for you: Yolanda Martins and Patricia Pliner have conducted a fascinating experiment about food preferences -- or, rather, what precise attributes make food disgusting.
Though disgust has long been considered to be a "basic emotion," there has been surprisingly little research on what foods evoke disgust (hopefully by now you've figured out that you probably don't want to read this post too close to a meal). The general consensus until Martins and Pliner's experiment was that the key to disgust was the "animal" elements of food. Researchers typically found that the more a food reminded people of animals, the more likely they were to be disgusted.
In some ways, it made sense: people chop meat into unrecognizable pieces, they avoid blood or offal, and they even name meats with new words: "beef" and "pork" instead of "cow" and "pig." But sometimes, the analysis didn't make much sense: theorists had to argue that people are disgusted by a slimy cucumber because it reminds them of a slimy animal.
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Posted by Dave Munger at 4:16 PM • Comments (9)
June 7, 2006
Category: Research • Taste
Synesthesia -- the ability to experience a sensation like vision in another mode, like hearing -- is thought to be quite rare. Yet all of us have the ability to combine sensory modes, and we do it every day. The modes we combine just happen to be ones we don't think about as often: taste and smell.
While vision gets the lion's share of attention in perception research, research on olfaction and taste has begun to be more prominent. However, though we know that the senses of taste and smell interact, few studies have explored the interaction between the two sensory modes. The problem is that chemical reactions can occur within the nose and mouth which actually affect the smell and taste of the substance being consumed, so it's unclear how to measure the impact of aroma versus taste on overall flavor.
A team led by Johann C. Pfeiffer has perfected a method to study the interaction of smell and taste while controlling for any chemical changes in the substance being tested: they measure the actual chemicals present within the taster's nose. If a chemical reaction occurs during tasting, the researchers can take this into account in their analysis.
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Posted by Dave Munger at 2:02 PM • Comments (1)
June 1, 2006
Category: Research • Taste
Several studies indicate that the brain regions responsible for taste overlap the areas responsible for detecting pain.
However, Dana Small and A. Vania Apkarian noted that little research has been conducted on the relationship to taste sensitivity and pain. They developed a simple experiment to see if there was a relationship.
Eleven volunteers with chronic back pain were matched with 11 normal volunteers, of similar age, gender, and education backgrounds. Each person was tested separately for sensitivity to four different kinds of tastes: bitter, salty, sweet, and sour. They each sampled a small cup of water with each of the four flavors, rating them on a scale of 0 to 100 for the strength of the taste sensation. Here are the results:
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Posted by Dave Munger at 12:30 PM • Comments (6)
May 24, 2006
Category: Research • Taste
We've discussed implicit attitudes on Cognitive Daily before, but never in the context of food. The standard implicit attitude task asks you to identify items belonging to two different categories. Consider the following lists. Use your mouse to click on items which are either pleasant or related to Genetically Modified foods (GM foods). (Clicking won't actually do anything, it's just a way of self-monitoring your progress)
Horrible
Good
Transgenic
Nasty
Crops
Wonderful
dislike
GE livestock
Now with this next list, do the same task, only click on items which are either unpleasant or related to GM foods.
Happy
Bad
GM plants
Likeable
Engineered salmon
Terrible
Modified tomatoes
Excellent
Which task was harder? I'm including a poll below the fold for you to register your results.
Read on »
Posted by Dave Munger at 2:00 PM • Comments (4)
May 10, 2006
Category: Perception • Research • Social • Taste
Recent research suggests that one of the reasons that as many as 97 percent of women and 68 percent of men experience food cravings is because of visual representations of food. When we picture food in our minds, our desire for the food increases. So why not just distract the visual system? One research team attempted just that, tempting volunteers with pictures of chocolate, and then distracting them with either a randomly changing visual image or an auditory task. The participants who watched the visual image experienced fewer food cravings.
I've attempted to reproduce the type of display these researchers suggest may distract you from your cravings (click on the image to start the animation).
The original research, however, didn't take into account whether participants were hungry. Perhaps if you're already hungry, the visual distraction won't help.
Read on »
Posted by Dave Munger at 4:47 PM • Comments (10)
January 23, 2006
Category: Development / Aging • Research • Taste
When I was a kid, school lunches didn't offer choice. I paid $1.10, and I was given four plops of foodlike substance. The entrees had names like "salisbury steak," "lasagne," or "beef stroganoff," but they all tasted about the same. Our "vegetable" was usually overcooked peas or green beans. There was a "starch," like mashed potatoes or a roll, and a dessert -- Jell-O or a cupcake -- typically the only edible item on the tray. If our lunch money wasn't stolen on the way to school, we were at least in theory presented with a balanced meal.
By the time my kids were in school, cafeteria philosophy had changed. Instead of serving up glop that no one ate, kids were given "healthy choices." They had charge accounts (no more stealing lunch money), and could select whatever they wanted to eat from a variety of options. What I don't understand is how the school nutritionists didn't realize that most kids were going to take three Jell-O's, two chocolate milks, and skip everything else. Jim regularly racked up charges of almost $10 a day. Needless to say, it didn't take long before we started resorting to homemade lunches.
I've finally found a study that addresses my concerns about putting children in charge of their own nutrition. A team led by Leonard H. Epstein gave 10- to 12-year-olds "budgets" to buy food in a laboratory setting. Then they varied the price of the foods to see if kids would modify their behavior: If we make junk food more expensive than healthy food, will kids substitute healthier foods?
Read on »
Posted by Dave Munger at 12:59 PM • Comments (7)
September 9, 2005
Category: Perception • Research • Taste
Taste is a notoriously difficult sense to study. My son Jim can't stand baked potatoes, but I can't get enough of them. I don't like watermelon, but the rest of my family gobbles it up. Even more perplexingly, I do like watermelon candy. With all the individual differences in taste, how can scientists learn anything specific about how the sense works?
The difficulties in taste study are compounded by the fact that taste is intimately associated with the sense of smell. Every kid knows to plug his nose when trying a food he or she doesn't like. Researchers must be constantly aware that differences in taste may also be due to smell. So when they want to answer a question like "how does the texture of a food impact its taste?", they know it will not be a simple matter to explore.
A group of scientists led by David Cook wanted to examine just that question. Initially, the problem seems simple enough: just cook up a bunch of food with different textures but the same amount of flavoring, and see how people perceive the taste. But then the problems come in: how do you vary texture? Will the texturing agents themselves change the food's flavor? What about individual differences between tasters? Do foods with different textures smell different?
The team started by trying two different flavors: sugar and iso-amyl acetate—a banana flavoring. They diluted each flavor in water, and then progressively varied the viscosity of each solution by mixing with three different tasteless thickening agents: guar gum, carageenan, and hydroxypropylmethyl cellulose (HPMC). (Now you know what about half the ingredients listed on your Hostess Twinkie are for!)
First they controlled for smell having taster smell and taste each sample and then place their nostrils on a device that physically measured the concentration of odorant that remained in their breath. In this way, they could determine how much odorant was present while the samples were being consumed, instead of relying on the tasters' perception of smell. They found no systematic difference in odor across the range of samples.
Next, a set of tasters who were trained and had two or more years' experience tasting food tried each sample, cleansing their palate with crackers and water between tastings, and rating them separately for "banana flavor" and "sweetness." As previous research had indicated, perception of flavor decreased as the solutions thickened. But why? Earlier studies had suggested that flavor diminished in proportion to the concentration of the thickening agent. While Cook et al.'s data confirmed this, they obtained different results for each thickener:
As the concentration of thickener increased, the perceived sweetness of solutions thickened with carrageenan decreased less than the other solutions. Perhaps concentration of thickener was not the best way model the impact of a thickener. So the team turned to the model of Jozef Kokini, who in the 1970s and 1980s developed a mathematical representation of how the mouth determines the viscosity of a substance. There's no reason to believe humans have detectors for carrageenan concentration in their mouths, but we do have nerves that can detect the sensation of touch. Perhaps we approximate viscosity by pressing food against the roof of our mouths with our tongues. Kokini developed a complex mathematical formula to model this method of determining "oral shear stress," or the amount of force it takes us to compress a thick liquid in our mouths. Cook et al. then applied this formula to their solutions and compared it to perceived sweetness:
Now, the results for each thickener follow a nearly identical path. Similar results were obtained for the banana flavoring.
Cook et al. conclude that we not only consider information from our taste buds and sensory organs in our noses, but also the feeling of the food in our mouths to determine flavor. While this research doesn't explain why Jim doesn't like potatoes, it does get us closer to understanding the many processes involved in the sensation of taste.
Cook, D. J., Hollowood, T. A., Linford, R., & Taylor, A. J. (2003). Oral shear stress predicts flavour perception in viscous solutions. Chemical Senses, 28, 11-23.
Posted by Dave Munger at 4:09 PM • Comments (1)
July 18, 2005
Category: Perception • Research • Taste
Baby rats, only 5 days old and still very much reliant on their mothers for food, can be artificially dehydrated by injecting them with a saline hypertonic solution. If a source of water is placed very close to the rat's snout, it will drink. But 21-day-old rats who have just been weaned from their mothers and who readily eat and drink on their own can be injected with the same saline hypertonic and won't drink any more than non-dehydrated rats the same age. The difference is that the older rats still have to decide to drink—the water is available in their cages, but they still must actively seek it in order to consume it. It's the difference between consummatory and appetitive behavior—to have an appetite, we must seek out food and water, not just consume it when it's placed in front of us. By the age of 35 days, rats have learned to drink when dehydrated:
W.G. Hall, H. Moore Arnold, and Keven P. Myers, in a study in Psychological Science, systematically tested rats by injecting half them with the saline hypertonic and removing the water from their cages for 60 minutes. When the water was returned, the dehydrated 21-day-old rats drank at the same rate as non-dehydrated rats their same age. But dehydrated 35-day-olds quickly consumed over four percent of their body weight in water. Clearly, in the two extra weeks following weaning, somehow the 35-day-olds had learned to detect when they were dehydrated. But how? Both 35-day-olds and 21-day-olds readily consume both dry food and water without assistance. Why don't 21-day-olds know when they're thirsty?
Hall and his colleagues suspected that 21-day-olds know to drink water under normal circumstances because their mouths feel dry after eating rat chow. When they are artificially dehydrated, they have no way of knowing they're thirsty, because they've only ever had to use dry mouth as a cue to thirst. They devised a clever experiment to test this theory. They raised rats from the time of weaning to the age of 35 days on a liquid-only diet and repeated their experiment, this time comparing 35-day-old chow-reared and liquid-reared rats. Here are their results:
Now dehydrated 35-day-old rats who had been raised on a liquid-only diet didn't drink significantly more than rats who weren't dehydrated. So the dry mouth associated with eating chow must have been the cue for rats to drink. When they never had that cue, they never learned to drink when they were dehydrated.
Interestingly, if the same rats were dehydrated artificially again after this experiment, they drank as much as the chow-reared rats. It only takes one experience with dehydration for rats to figure out what to do about it.
This study offers additional support for the study we discussed earlier about how amnesia patients don't realize they are full. Clearly building up an appetite involves more than sensing how much food and water is in our bodies—memory also plays a crucial role.
W.G. Hall, H. Moore Arnold, and Kevin P. Myers (2000). The acquisition of an appetite. Psychological Science 11(2), 101-105.
Posted by Dave Munger at 9:07 AM • Comments (0)
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