This work was supported by the National Institute of Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH) [grant number R01 DC011287] and NIH postdoctoral training grant (T32-DC00014). The content is solely the responsibility of the authors and does not necessarily represent the official views of NIDCD or NIH. The funding agencies had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation or contents of the manuscript.

This method has been approved by the Office of Regulatory Affairs at the University of Pennsylvania. For the research studies described herein, informed consent was obtained from each adult and informed assent from each child seven years of age or older.
1. General Considerations
<ol>
	<li>Conduct the preference test in a comfortable, private room that ideally has a sink for subjects to expectorate solutions during testing. If a sink is not available, give subjects a cup into which to expectorate.</li>
</ol>
2. Test Materials
<ol>
	<li>Obtain 1-L volumetric flasks, 1-L amber glass bottles, and 100 ml amber glass bottles for the preparation, storage, and dispensing of solutions. For testing, obtain the following materials: 30 ml disposable medicine cups for solutions; drinking cups containing water for rinsing in between trials; a stopwatch to monitor inter-pair and inter-series intervals; distilled water for solution preparation and for rinsing; a cup for expectoration (if the testing room does not contain a sink); a sheet of paper labeled with the numbers 1 and 2 representing the order of tasting; and a tracking grid (Figure 1) for recording data.</li>
</ol>
<img alt="Figure 1" src="/files/ftp_upload/54163/54163fig1.jpg" /> 
Figure 1. Tracking grids for recording sucrose preference. The solution presented first is underlined in each grid. <a href="https://www.jove.com/files/ftp_upload/54163/54163fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Clean and sterilize all bottles in an autoclave, and label each with the date and the stimulus label: A, B, C, D, E. Weigh the appropriate amount of sucrose to make solutions A through E (Table 1).</li>
	<li>Making one solution at a time, place the appropriate grams of sucrose (Table 1) in 1 L volumetric flask and fill to the line on the flask with distilled water. Mix to dissolve the sucrose. Once sucrose is dissolved, transfer the solution to the appropriately labeled 1 L amber glass bottle.</li>
	<li>Store the solution-containing bottles in the refrigerator (4 &#176;C) for a maximum of one week. Repeat step 2.3 to make the remaining four solutions. Solutions will be enough to test approximately 25-30 subjects.</li>
	<li>Construct tracking grid to record subject data, using template found in Figure 1. Label each grid with the Series number (1 or 2) and the concentrations of the sucrose solutions, and include space to record the start and end times of each series. Include a column on each grid to record notes as necessary during the test.</li>
</ol>
3. Subject and Testing Preparation
<ol>
	<li>Instruct adults to abstain from eating or drinking and instruct parents to not give child participants anything to eat or drink for at least 1 hr before testing.</li>
	<li>Two hr before testing, remove solutions from the refrigerator, transfer approximately 100 ml of each to the appropriately labeled 100 ml amber glass bottles, and allow the solutions to equilibrate to RT.</li>
	<li>Seat the subject at a table in front of the sheet of paper labeled with the numbers 1 and 2, and allow the subject to acclimate to the testing room and the tester for at least 10 min.</li>
</ol>
4. Psychophysical Method
Note: The preference test is a two-series, forced-choice, paired comparison tracking technique in which subjects are asked to taste (without swallowing) pairs of solutions of different concentrations and to point to the solution they prefer. Below are the introductory verbal instructions given to pediatric and adult subjects at the time of testing, followed by investigator instructions on how to conduct the preference test.
<ol>
	<li>Verbal Instructions to Subjects
	<ol>
		<li>Pediatric Subjects
		<ol>
			<li>Show the cups to the subject and say: &#34;We&#39;re going to play a game with things to taste. Here are two cups. You will taste what&#39;s inside the first cup, swish it around your mouth, but don&#39;t swallow, and I will tell you when to spit it out in the sink (or cup). You will then rinse your mouth with water, and then taste what&#39;s inside the second cup. I will tell you when to spit it out. Then I want you to point to which one you like better-the first one or the second one. You will then rinse your mouth two times with water, and we will do this again. There is no right or wrong answer; we want to know which one you like better.&#34;</li>
		</ol>
		</li>
		<li>Adolescents and Adults
		<ol>
			<li>Show the cups to the subject and say: &#34;We&#39;re going to give you solutions to taste. Here are two cups. You will taste what&#39;s inside the first cup, swish it around your mouth, but don&#39;t swallow, and I will tell you when to spit it out in the sink (or cup). You will then rinse your mouth with water, and then taste what&#39;s inside the second cup. I will tell you when to spit it out. Then I want you to point to which one you like better-the first one or the second one. You will then rinse your mouth two times with water, and we will do this again. There are no right or wrong answers; we want to know which one you like better.&#34;</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Investigator Instructions
	<ol>
		<li>For Series 1, begin by placing two cups, respectively containing 5 ml of solution B and 5 ml of solution D on a sheet of paper labeled with the numbers 1 and 2 in front of the subject: Place solution B on number 1 to be tasted first. Place solution D on number 2 and have the participant taste second. In Series 1, always place the weaker (lower) concentration solution of the pair in the number 1 position. Using the grid in Figure 1, underline the concentration that is presented first (solution B).</li>
		<li>Instruct the subject to taste the solution in position 1 by swishing; after 5 sec instruct the subject to expectorate, to rinse his or her mouth with water, and to expectorate again.</li>
		<li>Instruct the subject to taste the solution in position 2 by swishing, and to expectorate after 5 sec.</li>
		<li>Ask the subject to point to the solution the subject likes better. If the subject says they like both, instruct the subject to again point to the one they like better. Circle the X on the grid (Figure 1) that corresponds to the subject&#39;s preferred concentration.</li>
		<li>Instruct the subject to rinse his or her mouth twice with water and to expectorate. Use the timer to wait 1 min before presenting the next pair of solutions.</li>
		<li>For the second comparison of solutions in Series 1, pair the preferred concentration from the first comparison with the lower adjacent concentration. For example, if the subject prefers solution D to solution B in the first pair, then present the second pair consisting of solutions C and D. Place solution C (the lower concentration) in position 1 and solution D in position 2. Indicate which solutions are being presented by marking X&#39;s on the grid and underline the X that corresponds to the solution presented in position 1 (in this case Solution C).</li>
		<li>Repeat this process until the subject chooses the same concentration when presented with both a lower and higher adjacent concentration (e.g., if the subject chooses C when paired both with B and with D), or when the subject chooses either the lowest (A) or the highest concentration (E) twice consecutively.</li>
		<li>Record each subject&#39;s preferred concentration from Series 1 on the grid, and wait 3 min before beginning Series 2.</li>
		<li>For Series 2, pour 5 ml of each of solutions B and D into disposable cups, and place solution D on number 1 and solution B on number 2 in front of the subject. In Series 2, the stronger (higher) concentration solution of the pair is always placed in the number 1 position. Using the grid, underline the concentration that is presented first (D).</li>
		<li>Instruct the subject to taste and expectorate the solutions following the protocol used for Series 1 as outlined in steps 4.2.2-4.2.8.</li>
		<li>For the second comparison of solutions in Series 2, pair the preferred concentration from the first comparison with the higher adjacent concentration. For example, if the subject prefers solution D to solution B in the first pair, present solutions E and D in the second pair, placing solution E (the higher concentration) in position 1.</li>
		<li>Repeat this process until the subject chooses the same concentration when presented with both a lower and higher adjacent concentration, or when the subject chooses either the lowest or the highest concentration twice consecutively.</li>
		<li>Record the subject&#39;s preferred concentration from Series 2 by circling it on the grid.</li>
		<li>Determine the subject&#39;s preferred level of sucrose by calculating the geometric mean of the concentrations chosen in the two series (the square root of the product of the two concentrations): 
		Geometric Mean = &#8730; (series 1 preference) x (series 2 preference)</li>
	</ol>
	</li>
</ol>

<ol><li>Desor, J. A., Maller, O., Turner, R. E. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aDesor%2C+JA+%22Preference+for+sweet+in+humans%3A+infants%2C+children+and+adults.+In+Taste+and+development%3A+the+genesis+of+sweet+preference%22">Preference for sweet in humans: infants, children and adults. In Taste and development: the genesis of sweet preference</a>. Weiffenbach, J. M. , US Government Printing Office. 161-172 (1977).</li>
<li>Mennella, J. A. Taste and smell. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aMennella%2C+JA+%22Pediatric+Neurology%3A+Principles+and+Practice%22">Pediatric Neurology: Principles and Practice</a>. Swaiman, K. F., Ashwall, S., Ferriero, D. , CV Mosby Company. Ch. 9 135-149 (2006).</li>
<li>Birch, L. L., Anzman-Frasca, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Learning+to+prefer+the+familiar+in+obesogenic+environments%5BTitle%5D)+AND+%22Nestle+Nutr+Workshop+Ser+Pediatr+Program%22%5BJournal%5D)">Learning to prefer the familiar in obesogenic environments.</a> Nestle Nutr Workshop Ser Pediatr Program. 68, 187-196 (2011).</li>
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<li>Li, X. E., Lopetcharat, K., Drake, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Parents%27+and+children%27s+acceptance+of+skim+chocolate+milks+sweetened+by+monk+fruit+and+stevia+leaf+extracts%5BTitle%5D)+AND+%22J+Food+Sci%22%5BJournal%5D)">Parents' and children's acceptance of skim chocolate milks sweetened by monk fruit and stevia leaf extracts.</a> J Food Sci. 80 (5), 1083-1092 (2015).</li>
<li>Guinard, J. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sensory+and+consumer+testing+with+children%5BTitle%5D)+AND+%22Trends+Food+Sci+Technol%22%5BJournal%5D)">Sensory and consumer testing with children.</a> Trends Food Sci Technol. 11 (8), 273-283 (2000).</li>
<li>Popper, R., Kroll, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Conducting+sensory+research+with+children%5BTitle%5D)+AND+%22J+Sens+Stud%22%5BJournal%5D)">Conducting sensory research with children.</a> J Sens Stud. 20 (1), 75-87 (2005).</li>
<li>Leon, F., Couronne, T., Marcuz, M. C., Koster, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Measuring+food+liking+in+children%3A+a+comparison+on+non+verbal+methods%5BTitle%5D)+AND+%22Food+Qual+Prefer%22%5BJournal%5D)">Measuring food liking in children: a comparison on non verbal methods.</a> Food Qual Prefer. 10 (2), 93-100 (1999).</li>
<li>Mennella, J. A., Lukasewycz, L. D., Griffith, J. W., Beauchamp, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Evaluation+of+the+Monell+forced-choice%2C+paired-comparison+tracking+procedure+for+determining+sweet+taste+preferences+across+the+lifespan%5BTitle%5D)+AND+%22Chem+Senses%22%5BJournal%5D)">Evaluation of the Monell forced-choice, paired-comparison tracking procedure for determining sweet taste preferences across the lifespan.</a> Chem Senses. 36 (4), 345-355 (2011).</li>
<li>Coldwell, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gustation+assessment+using+the+NIH+Toolbox%5BTitle%5D)+AND+%22Neurology%22%5BJournal%5D)">Gustation assessment using the NIH Toolbox.</a> Neurology. 80 (11), Suppl 3 20-24 (2013).</li>
<li>Beauchamp, G. K., Cowart, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preference+for+high+salt+concentrations+among+children%5BTitle%5D)+AND+%22Dev+Psychol%22%5BJournal%5D)">Preference for high salt concentrations among children.</a> Dev Psychol. 26 (4), 539-545 (1990).</li>
<li>Cowart, B. J., Beauchamp, G. K. Early development of taste perception. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aCowart%2C+BJ+%22Psychological+Basis+of+Sensory+Evaluation%22">Psychological Basis of Sensory Evaluation</a>. McBride, R., MacFie, H. , Elsevier. 1-17 (1990).</li>
<li>Mennella, J. A., Pepino, M. Y., Reed, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Genetic+and+environmental+determinants+of+bitter+perception+and+sweet+preferences%5BTitle%5D)+AND+%22Pediatrics%22%5BJournal%5D)">Genetic and environmental determinants of bitter perception and sweet preferences.</a> Pediatrics. 115 (2), 216-222 (2005).</li>
<li>Mennella, J. A., Pepino, M. Y., Lehmann-Castor, S. M., Yourshaw, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sweet+preferences+and+analgesia+during+childhood%3A+effects+of+family+history+of+alcoholism+and+depression%5BTitle%5D)+AND+%22Addiction%22%5BJournal%5D)">Sweet preferences and analgesia during childhood: effects of family history of alcoholism and depression.</a> Addiction. 105 (4), 666-675 (2010).</li>
<li>Mennella, J. A., Finkbeiner, S., Lipchock, S. V., Hwang, L. D., Reed, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Preferences+for+salty+and+sweet+tastes+are+elevated+and+related+to+each+other+during+childhood%5BTitle%5D)+AND+%22PLoS+One%22%5BJournal%5D)">Preferences for salty and sweet tastes are elevated and related to each other during childhood.</a> PLoS One. 9 (3), e92201(2014).</li>
<li>Kim, J. Y., Prescott, J., Kim, K. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Patterns+of+sweet+liking+in+sucrose+solutions+and+beverages%5BTitle%5D)+AND+%22Food+Qual+Prefer%22%5BJournal%5D)">Patterns of sweet liking in sucrose solutions and beverages.</a> Food Qual Prefer. 36, 96-103 (2014).</li>
<li>Pepino, M. Y., Mennella, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Factors+contributing+to+individual+differences+in+sucrose+preference%5BTitle%5D)+AND+%22Chem+Senses%22%5BJournal%5D)">Factors contributing to individual differences in sucrose preference.</a> Chem Senses. 30, Suppl 1 319-320 (2005).</li>
<li>Mennella, J. A., Finkbeiner, S., Reed, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+proof+is+in+the+pudding%3A+children+prefer+lower+fat+but+higher+sugar+than+do+mothers%5BTitle%5D)+AND+%22Int+J+Obes+%28Lond%29%22%5BJournal%5D)">The proof is in the pudding: children prefer lower fat but higher sugar than do mothers.</a> Int J Obes (Lond). 36 (10), 1285-1291 (2012).</li>
<li>Pepino, M. Y., Mennella, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+of+cigarette+smoking+and+family+history+of+alcoholism+on+sweet+taste+perception+and+food+cravings+in+women%5BTitle%5D)+AND+%22Alcohol+Clin+Exp+Res%22%5BJournal%5D)">Effects of cigarette smoking and family history of alcoholism on sweet taste perception and food cravings in women.</a> Alcohol Clin Exp Res. 31 (11), 1891-1899 (2007).</li>
<li>Schmidt, H. J., Beauchamp, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Adult-like+odor+preferences+and+aversions+in+three-year-old+children%5BTitle%5D)+AND+%22Child+Dev%22%5BJournal%5D)">Adult-like odor preferences and aversions in three-year-old children.</a> Child Dev. 59 (4), 1136-1143 (1988).</li>
<li>Temple, E. C., Hutchinson, I., Laing, D. G., Jinks, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Taste+development%3A+differential+growth+rates+of+tongue+regions+in+humans%5BTitle%5D)+AND+%22Brain+Res+Dev+Brain+Res%22%5BJournal%5D)">Taste development: differential growth rates of tongue regions in humans.</a> Brain Res Dev Brain Res. 135 (1-2), 65-70 (2002).</li>
<li>Mennella, J. A., Bobowski, N. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+sweetness+and+bitterness+of+childhood%3A+Insights+from+basic+research+on+taste+preferences%5BTitle%5D)+AND+%22Physiol+Behav%22%5BJournal%5D)">The sweetness and bitterness of childhood: Insights from basic research on taste preferences.</a> Physiol Behav. , (2015).</li>
<li>Bertino, M., Beauchamp, G. K., Engelman, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Long-term+reduction+in+dietary+sodium+alters+the+taste+of+salt%5BTitle%5D)+AND+%22Am+J+Clin+Nutr%22%5BJournal%5D)">Long-term reduction in dietary sodium alters the taste of salt.</a> Am J Clin Nutr. 36 (6), 1134-1144 (1982).</li>
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</ol>

The authors declare they have no competing financial interests.

The Monell two-series, forced-choice, paired-comparison tracking technique detailed here has been consistently used to determine sweet taste preference among nearly 2,000 racially and ethnically diverse subjects as young as 5 years of age. The preference test, which for children is embedded within the context of a game, is sensitive to the cognitive limitations of children and is a much-needed method to fill the gap in age-appropriate psychophysical research methods for pediatric populations. If completed as described, w...

The sense of taste controls one of the most important decisions we make: whether to eat something or not. From birth, humans show a strong liking for sweet taste1-it attracts the newborn to mother&#39;s milk and signals the presence of calories from nutrient-dense foods (e.g., fruits)2. Although this inborn trait confers an advantage for survival in an environment of scarcity, an individual&#39;s liking for sweet coupled with a food environment that supplies sugar in abundance has resulted in overconsumption of sweetened foods3. Current estimates suggest that 13.1-17.5% of children&#39;s and 11.2-14.5% of adults&#39; total energy intake is derived from added sugars4; in both cases, levels are well above national and international dietary recommendations5,6.
Despite the importance of taste in determining food choice and intake, and the association between diet and health, methodologies to accurately assess taste hedonics are limited, particularly for use with pediatric populations7-9. One of the methods most commonly used with children is hedonic category scaling10-12, which involves choosing a response from a series of discrete alternatives that signify increasing preference. These alternatives are often depicted with smiley faces10 or with verbal descriptors ranging from &#34;super bad&#34; to &#34;super good&#34;13, and are useful for determining whether a child likes the taste of a stimulus or not. Ranking procedures, in which a subject is required to order several choices by how well they are liked (e.g., from most to least liked), are also frequently used and are intended to convey information on relative liking of stimuli13,14. Although both methods provide valuable information on two separate dimensions of hedonic response, neither directly assesses taste preference, specifically the concentration of a stimulus perceived to be of optimal palatability. The method described herein was specifically developed to determine an individual&#39;s most preferred level of a tastant through direct comparisons of pairs of stimuli of varying concentrations, bypassing the need to infer preference from ratings of stimuli evaluated individually in a sequential monadic manner, as is often practiced in psychophysical testing.
Here, we detail the protocol for the Monell two-series, forced-choice, paired-comparison tracking technique for determining sweet taste preferences15,16. The method was first developed for measuring salt preference17,18. It was later modified for measuring sucrose preference19,20, tested for measures of both reliability and validity15, and selected for the National Institutes of Health Toolbox Assessment for Neurological and Behavioral Function as the method of choice to assess children&#39;s sweet taste preference for clinical, epidemiological, and longitudinal studies16. The method, which typically takes no more than 15 min to complete, has been used to measure the most preferred level of sucrose among hundreds of children, adolescents, and adults15,19-25. In a study of 949 subjects, only 5% of the 356 children tested were unable to complete both series of the sweet preference test due to unfocused behavior or failure to understand the task15, highlighting the appropriateness of the method for pediatric populations.
In brief, following a 1-hr fast, consenting subjects are presented with pairs of sucrose solutions of varying concentrations (3-36%) in a two-series test, with the lower concentration presented in the first position in each pair in the first series. Subjects taste the pair of solutions and are instructed to point to the solution they prefer. Subsequent pairs of solutions are presented based on the subject&#39;s preferred concentration in the previous pair. The test continues until the subject selects the same sucrose concentration twice relative to both a lower and a higher concentration, or until the subject selects the lowest (3%) or highest (36%) concentration twice consecutively. The protocol is then repeated in reverse order, with higher concentrations presented in the first position in each pair. On average, the method requires 7 presentations of solution pairs16.
The described method is particularly effective for use with children because it accounts for several methodological concerns often overlooked in other psychophysical tests: (1) the method is short in duration and does not require a sustained attention span; (2) the two-series protocol in which solution concentrations are counterbalanced between the series controls for position bias; (3) the forced-choice procedure circumvents children&#39;s inclination to answer questions in the affirmative26; (4) use of a whole-mouth instead of a regional-tasting protocol accounts for age-related differences in the growth and size of the tongue27; and (5) instructing children to point to their most preferred concentration of sucrose addresses potential cognitive limitations by eliminating the need for a verbal response19.
Since its development, the Monell two-series, forced-choice, paired-comparison tracking technique has revealed consistent differences in sweet taste preference as a function of age15,28 , race/ethnicity15,23, taste receptor genotype19,24, family history of alcoholism20,25, and depressive symptomatology among pediatric populations20. In addition, sweet taste preference as measured by this method is associated with preference for sugar in foods and beverages15,19,21,22, providing evidence of criterion-related validity and a measure of insight into the association between an individual&#39;s sweet preference and their dietary sugar intake.

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psychophysical tracking method to measure taste preferences in children and adults

The Monell two-series, forced-choice, paired-comparison tracking method provides a reliable measure of sweet taste preferences from childhood to adulthood. The method, which is identical for children, adolescents, and adults, is of short duration (&#60; 15 min), does not rely on sustained attention or place demands on memory (which would yield spurious age differences), and minimizes the impact of language development, making this method amenable to the cognitive limitations of pediatric populations. In this whole-mouth tasting method, subjects are asked to taste (without swallowing) pairs of solutions of different sucrose concentrations and to point to the solution they prefer. Each subsequent pair contains the participant&#39;s preceding preferred concentration and an adjacent stimulus concentration. The procedure continues until the subject chooses either a given concentration of sucrose when paired with both a higher and a lower concentration, or the highest or lowest concentration two consecutive times. Subjects are prevented from reaching response criteria on the basis of first or second position bias by the two-series design of the method, which counterbalances the order of solution presentation within each pair between the series (the weaker concentration is presented first in Series 1, second in Series 2). The geometric mean of the two sucrose concentrations chosen in Series 1 and 2 is an estimate of the participant&#39;s most preferred level of sucrose. Sucrose preference as determined with this laboratory-based measure has been shown to be associated with preference for sugars in foods and beverages and with taste receptor genotype, family history of alcoholism, and race/ethnicity, as well as depressive symptomatology among pediatric populations. The method has real-world relevance and has been applied to determine most preferred level of other tastes (e.g., salt), making it a valuable psychophysical tool.

Figure 2 contains the tracking grid results from one representative subject. This subject&#39;s most preferred level of sucrose, 4.2% w/v, was determined by calculating the geometric mean of the sucrose concentrations chosen in Series 1 (6% w/v) and Series 2 (3% w/v). In cases where the subject only completes one of the series, the geometric mean obviously cannot be calculated. Further analysis can focus on data obtained from Series 1 separately from Series 215...

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Psychophysical Tracking Method to Measure Taste Preferences in Children and Adults

Sweet taste has powerful hedonic appeal among people of all ages, particularly children. Described herein is a reliable and valid method that can be used to determine the level of sweetness most preferred, making it a valuable psychophysical tool for scientists.

The Monell two-series, forced-choice, paired-comparison tracking method provides a reliable measure of sweet taste preferences from childhood to ...

psychophysical-tracking-method-to-measure-taste-preferences-children

Research

JoVE Journal

Behavior

17.7K Views.  Monell Chemical Senses Center. Sweet taste has powerful hedonic appeal among people of all ages, particularly children. Described herein is a reliable and valid method that can be used to determine the level of sweetness most preferred, making it a valuable psychophysical tool for scientists.

Video: Psychophysical Tracking Method to Measure Taste Preferences in Children and Adults

The Crossmodal Congruency Task as a Means to Obtain an Objective Behavioral Measure in the Rubber Hand Illusion Paradigm

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden hand is touched. If the viewed and felt touches are given at the same time then this is sufficient to induce the compelling experience that the rubber hand is one's own hand. The RHI can be used to investigate exactly how the brain constructs distinct body representations for one's own body. Such representations are crucial for successful interactions with the external world. To obtain a subjective measure of the RHI, researchers typically ask participants to rate statements such as "I felt as if the rubber hand were my hand". Here we demonstrate how the crossmodal congruency task can be used to obtain an objective behavioral measure within this paradigm.
The variant of the crossmodal congruency task we employ involves the presentation of tactile targets and visual distractors. Targets and distractors are spatially congruent (i.e. same finger) on some trials and incongruent (i.e. different finger) on others. The difference in performance between incongruent and congruent trials - the crossmodal congruency effect (CCE) - indexes multisensory interactions. Importantly, the CCE is modulated both by viewing a hand as well as the synchrony of viewed and felt touch which are both crucial factors for the RHI.
The use of the crossmodal congruency task within the RHI paradigm has several advantages. It is a simple behavioral measure which can be repeated many times and which can be obtained during the illusion while participants view the artificial hand. Furthermore, this measure is not susceptible to observer and experimenter biases. The combination of the RHI paradigm with the crossmodal congruency task allows in particular for the investigation of multisensory processes which are critical for modulations of body representations as in the RHI.

We demonstrate how an objective measure can be employed in the widely employed rubber hand illusion paradigm. This measure is obtained by modifying the well-established crossmodal congruency task. This task allows the investigation of multisensory processes which are critical for modulations of body representations as in the rubber hand illusion.

The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants' own hidden ...

A Method to Quantify Visual Information Processing in Children Using Eye Tracking

Visual problems that occur early in life can have major impact on a child's development. Without verbal communication and only based on observational methods, it is difficult to make a quantitative assessment of a child's visual problems. This limits accurate diagnostics in children under the age of 4 years and in children with intellectual disabilities. Here we describe a quantitative method that overcomes these problems. The method uses a remote eye tracker and a four choice preferential looking paradigm to measure eye movement responses to different visual stimuli. The child sits without head support in front of a monitor with integrated infrared cameras. In one of four monitor quadrants a visual stimulus is presented. Each stimulus has a specific visual modality with respect to the background, e.g., form, motion, contrast or color. From the reflexive eye movement responses to these specific visual modalities, output parameters such as reaction times, fixation accuracy and fixation duration are calculated to quantify a child's viewing behavior. With this approach, the quality of visual information processing can be assessed without the use of communication. By comparing results with reference values obtained in typically developing children from 0-12 years, the method provides a characterization of visual information processing in visually impaired children. The quantitative information provided by this method can be advantageous for the field of clinical visual assessment and rehabilitation in multiple ways. The parameter values provide a good basis to: (i) characterize early visual capacities and consequently to enable early interventions; (ii) compare risk groups and follow visual development over time; and (iii), construct an individual visual profile for each child.

A method is described to quantify the quality of visual information processing based on reflexive eye movements in response to specific visual modalities. Reaction times and fixation output parameters are used to characterize visual performance in children with and without visual impairments from 6 months of age.

Visual problems that occur early in life can have major impact on a child's development. Without verbal communication and only based on observational ...

Measuring Oral Fatty Acid Thresholds, Fat Perception, Fatty Food Liking, and Papillae Density in Humans

Emerging evidence from a number of laboratories indicates that humans have the ability to identify fatty acids in the oral cavity, presumably via fatty acid receptors housed on taste cells. Previous research has shown that an individual&#39;s oral sensitivity to fatty acid, specifically oleic acid (C18:1) is associated with body mass index (BMI), dietary fat consumption, and the ability to identify fat in foods. We have developed a reliable and reproducible method to assess oral chemoreception of fatty acids, using a milk and C18:1 emulsion, together with an ascending forced choice triangle procedure. In parallel, a food matrix has been developed to assess an individual&#39;s ability to perceive fat, in addition to a simple method to assess fatty food liking. As an added measure tongue photography is used to assess papillae density, with higher density often being associated with increased taste sensitivity.

Oral chemoreception of fatty acids and the association with diet and fatty food preferences may enable the identification of mechanisms involved with the development of obesity and why dietary changes may be difficult for many individuals.

Emerging evidence from a number of laboratories indicates that humans have the ability to identify fatty acids in the oral cavity, presumably via fatty ...

Neuroscience

Denver Papillae Protocol for Objective Analysis of Fungiform Papillae

The goal of the Denver Papillae Protocol is to use a dichotomous key to define and prioritize the characteristics of fungiform papillae (FP) to ensure consistent scoring between scorers. This protocol builds off of a need that has arisen from the last two decades of taste research using FP as a proxy for taste pore density. FP density has historically been analyzed using Miller &#38; Reedy&#8217;s 1990 characterizations of their morphology: round, stained lighter, large, and elevated. In this work, the authors forewarned that stricter definitions of FP morphology needed to be outlined. Despite this call to action, follow up literature has been scarce, with most studies continuing to cite Miller &#38; Reedy&#8217;s original work. Consequently, FP density reports have been highly variable and, combined with small sample sizes, may contribute to the discrepant conclusions on the role of FP in taste sensitivity. The Genetics of Taste Lab explored this apparent inconsistency in counting and found that scorers were individually prioritizing the importance of these characteristics differently and had no guidance for when a papilla had some, but not all, of the reported qualities of FP. The result of this subjectivity is highly variable FP counts of the same tongue image. The Denver Papillae Protocol has been developed to remedy this consequence through use of a dichotomous key that further defines and prioritizes the importance of the characteristics put forth by Miller &#38; Reedy. The proposed method could help create a standard way to quantify FP for researchers in the field of taste and nutritional studies.

Here we present a protocol to measure fungiform papilla density from digital photographs. This method builds prioritization and objective characteristic metrics into the original descriptive work on fungiform papillae by Miller &#38; Reedy (1990).

The goal of the Denver Papillae Protocol is to use a dichotomous key to define and prioritize the characteristics of fungiform papillae (FP) to ensure ...

Taste Preference Assay for Adult Drosophila

Olfactory and gustatory perception of the environment is vital for animal survival. The most obvious application of these chemosenses is to be able to distinguish good food sources from potentially dangerous food sources. Gustation requires physical contact with a chemical compound which is able to signal through taste receptors that are expressed on the surface of neurons. In insects, these gustatory neurons can be located across the animal's body allowing taste to play an important role in many different behaviors. Insects typically prefer compounds containing sugars, while compounds that are considered bitter tasting are avoided. Given the basic biological importance of taste, there is intense interest in understanding the molecular mechanisms underlying this sensory modality. We describe an adult Drosophila taste assay which reflects the preference of the animals for a given tastant compound. This assay may be applied to animals of any genetic background to examine the taste preference for a desired soluble compound.

Taste Preference Assay for Adult Drosophila

Taste is an important sensory process which facilitates attraction to beneficial substances and avoidance of toxic substances. This protocol describes a simple ingestion assay for determining Drosophila gustatory preference for a given chemical compound.

Olfactory and gustatory perception of the environment is vital for animal survival.  The most obvious application of these chemosenses is to be able to ...

New Methods to Study Gustatory Coding

The sense of taste allows animals to detect chemicals in the environment, giving rise to behaviors critical for survival. When Gustatory Receptor Neurons (GRNs) detect tastant molecules, they encode information about the identity and concentration of the tastant as patterns of electrical activity that then propagate to follower neurons in the brain. These patterns constitute internal representations of the tastant, which then allow the animal to select actions and form memories. The use of relatively simple animal models has been a powerful tool to study basic principles in sensory coding. Here, we propose three new methods to study gustatory coding using the moth Manduca sexta. First, we present a dissection procedure for exposing the maxillary nerves and the subesophageal zone (SEZ), allowing recording of the activity of GRNs from their axons. Second, we describe the use of extracellular electrodes to record the activity of multiple GRNs by placing tetrode wires directly into the maxillary nerve. Third, we present a new system for delivering and monitoring, with high temporal precision, pulses of different tastants. These methods allow the characterization of neuronal responses in vivo directly from GRNs before, during and after tastants are delivered. We provide examples of voltage traces recorded from multiple GRNs, and present an example of how a spike sorting technique can be applied to the data to identify the responses of individual neurons. Finally, to validate our recording approach, we compare extracellular recordings obtained from GRNs with tetrodes to intracellular recordings obtained with sharp glass electrodes.

We present three new methods to study gustatory coding. Using a simple animal, the moth Manduca sexta (Manduca), we describe a dissection protocol, the use of extracellular tetrodes to record the activity of multiple gustatory receptor neurons, and a system for delivering and monitoring precisely timed pulses of tastants.

The sense of taste allows animals to detect chemicals in the environment, giving rise to behaviors critical for survival. When Gustatory Receptor Neurons ...

Taste Exam: A Brief and Validated Test

The emerging importance of taste in medicine and biomedical research, and new knowledge about its genetic underpinnings, has motivated us to supplement classic taste-testing methods in two ways. First, we explain how to do a brief assessment of the mouth, including the tongue, to ensure that taste papillae are present and to note evidence of relevant disease. Second, we draw on genetics to validate taste test data by comparing reports of perceived bitterness intensity and inborn receptor genotypes. Discordance between objective measures of genotype and subjective reports of taste experience can identify data collection errors, distracted subjects or those who have not understood or followed instructions. Our expectation is that fast and valid taste tests may persuade researchers and clinicians to assess taste regularly, making taste testing as common as testing for hearing and vision. Finally, because many tissues of the body express taste receptors, taste responses may provide a proxy for tissue sensitivity elsewhere in the body and, thereby, serve as a rapid, point-of-care test to guide diagnosis and a research tool to evaluate taste receptor protein function.

This protocol measures human taste responses and includes a brief anatomical assessment, a short taste test, and a validation method using the subject&#39;s reported sensation and taste receptor genotype.

The emerging importance of taste in medicine and biomedical research, and new knowledge about its genetic underpinnings, has motivated us to supplement ...

Medicine

Psychophysical Tracking Method to Assess Taste Detection Thresholds in Children, Adolescents, and Adults: The Taste Detection Threshold (TDT) Test

This paper describes a two-alternative, forced-choice, staircase, tracking procedure, called the Taste Detection Threshold (TDT) test, that provides a reliable measure of sweet, salty, and umami taste detection thresholds from childhood to adulthood. Advantages of the method include procedures that are identical for children and adults, thus allowing the determination of age-related and individual differences in taste perception, if any, and tasks that can be completed in a relatively short time frame, do not rely on continuous attention or require memorization, control for subjective response biases, and minimize the impact of language development. After a 1 hour fast, participants are presented with pairs of solutions; in each pair, one solution is water, and the other solution contains varying concentrations of the tastant.
Using a whole-mouth tasting method, participants taste each solution (without swallowing and with rinsing between tastings) and then point to the solution with a taste or that tastes different from water. The concentration of the stimulus in the subsequent pair increases after a single incorrect response and decreases after two consecutive correct responses. A reversal occurs when the concentration sequence changes direction. The task is deemed completed after the occurrence of four reversals, provided there are a maximum of two dilution steps between two successive reversals, and the series of reversals do not form an ascending pattern. These additional criteria ensure greater reliability in outcomes. The TDT is then calculated as the geometric mean of the concentrations of the four reversals. This method has real-world relevance as it provides information on a dimension of taste perception that is independent of hedonics, and that can change with aging and certain disease states, making it a valuable psychophysical test.

Psychophysical Tracking Method to Assess Taste Detection Thresholds in Children, Adolescents, and Adults: The Taste Detection Threshold TDT Test

Psychophysical tools measure the functionality of the taste system for both research and health assessment purposes. This paper describes a method to measure taste detection thresholds that can determine the lowest concentration of sucrose, sodium chloride, or monosodium glutamate that can be tasted by individuals as young as 6 years.

This paper describes a two-alternative, forced-choice, staircase, tracking procedure, called the Taste Detection Threshold (TDT) test, that provides a ...

A Novel Method for Enhanced Analysis of Insect Taste Neuron Activity

Base Recording: A Technique for Analyzing Responses of Taste Neurons in Drosophila

Insects taste the external world through taste hairs, or sensilla, that have pores at their tips. When a sensillum comes into contact with a potential food source, compounds from the food source enter through the pore and activate neurons within. For over 50 years, these responses have been recorded using a technique called tip recording. However, this method has major limitations, including the inability to measure neural activity before or after stimulus contact and the requirement for tastants to be soluble in aqueous solutions. We describe here a technique that we call base recording, which overcomes these limitations. Base recording allows the measurement of taste neuron activity before, during, and after the stimulus. Thus, it allows extensive analysis of OFF responses that occur after a taste stimulus. It can be used to study hydrophobic compounds such as long-chain pheromones that have very low solubility in water. In summary, base recording offers the advantages of single-sensillum electrophysiology as a means of measuring neuronal activity - high spatial and temporal resolution, without the need for genetic tools - and overcomes key limitations of the traditional tip recording technique.

Author Spotlight: Advances in Chemoreception &#8211; From Insect Odor Receptors to Non-Coding RNAs

A rarely used method of electrophysiological recording, base recording, allows analysis of features of taste coding that cannot be examined by conventional recording methods. Base recording also allows the analysis of taste responses to hydrophobic stimuli that cannot be studied using traditional electrophysiological methods.

Insects taste the external world through taste hairs, or sensilla, that have pores at their tips. When a sensillum comes into contact with a potential ...

Taste Preference Assay: A Method for Measuring Feeding Behavior in Drosophila

Source: Bantel, A. P. and Tessier, C. R. <a href="https://www.jove.com/video/54403/" target="_blank">Taste Preference Assay for Adult Drosophila</a>. J. Vis. Exp. (2016).
This video describes the taste preference assay, a behavioral method used to measure attraction or avoidance towards colored solutions that taste differently by assessing the fly&#39;s abdominal coloration after ingestion of the preferred substance. The featured protocol demonstrates the procedure used to measure flies&#39; preference towards solutions of varying sucrose concentrations.

Source: Bantel, A. P. and Tessier, C. R. Taste Preference Assay for Adult Drosophila. J. Vis. Exp. (2016).
This video describes the taste preference ...

Psychophysical Tracking Method to Measure Taste Preferences in Children and Adults

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