THE POWER OF SENSORY DISCRIMINATION METHODS REVISITED

An overlooked compound contributing to boar taint and consumer rejection of meat products: 2-Aminoacetophenone

Mainly skatole and androstenone have so far been considered causative for boar taint. Using a mixed methods approach it is shown herein that 2-aminoacetophenone (AAP) affects human perception of pork, too. We explored the importance of AAP in four trials: (1) chemical analyses of 221 fat samples from boar carcasses revealed that AAP occurs, on average, in similar quantities as skatole while the levels of androstenone being four-fold. (2) ranking tests with mixtures of androstenone and/or skatole with AAP presented on smell strips to trained sensory assessors showed that AAP amplifies boar odour. In order to study AAP's importance in meat products, four experimental variants of Lyon type sausage were then produced: a control, a product with added skatole (0.075 μg/g fat tissue), with added AAP (0.075 μg/g fat tissue), and with addition of both compounds. (3) results of a consumer discrimination test panel (n = 71) showed that, when added to a sausage system, APP causes a sensory difference of similar size as skatole while the methodology chosen affects the effect size: tetrad tests proved to be more sensitive than duo trio difference tests, in the tetrad test a sensory difference expressed as d' (d-prime) of 1.0 was reached. (4) a hedonic consumer test (n = 121) finally revealed that APP decreased consumer liking of the APP-spiked sausage - even to a stronger extent than skatole. APP caused significant drops in smell, taste, mouth-feel, after-taste and overall liking in Lyoner. Overall the findings suggest that, in the context of pork meat, AAP is of similar olfactory importance as skatole.

Fibre4life: Investigating older adults dietary fibre preferences and the role of targeted educational materials on modulating future dietary fibre intake

The UK has an ever-increasing ageing population; hence, promoting balanced nutrition can have fundamental health and cost benefits. In addition, the majority of older adults' dietary fibre intake is below recommendations and this is despite its well-cited benefits; therefore, more emphasis should be placed on identifying viable age-suitable strategies to overcome the associated dietary fibre-related knowledge gap. Accordingly, one hundred and seventy older adults (65-87 years) were recruited to partake in two survey related studies: (1) initial insights (e.g., dietary fibre-related knowledge, awareness, attitudes and behaviour as well as information preferences) were captured to inform the design of educational materials; and (2) the impact of two targeted educational materials on modulating older adults' future dietary fibre intake was tested. Older adults were willing to learn more about dietary fibre and requested additional information relating to its benefits, recommendations and food-based examples in a clear and accessible format. Therefore, two educational materials (factsheet and practical tips) were developed encompassing key themes. Overall, older adults engaged with the educational materials (regardless of topic and format); thus, demonstrating the potential benefits of this approach going forwards. There was strong agreement with all variables: learning something new, change future dietary fibre intake, format liking, content engaging and share with others as well as the overall experience being cited as useful/helpful. Going forwards, importance should be placed on measuring dietary fibre consumption post engaging with educational materials. In addition, utilising a holistic approach incorporating support from different sources (e.g., health professionals, government, food companies, supermarkets and community) could be fundamental in helping older adults to consume more dietary fibre and subsequently contributing to positive health outcomes.

Sensory Analysis and Consumer Preference: Best Practices

Sensory science is a multidisciplinary field that encompasses a wide variety of established and newly developed tests to document human responses to stimuli. Sensory tests are not limited to the area of food science but they find wide application within the diverse areas of the food science arena. Sensory tests can be divided into two basic groups: analytical tests and affective tests. Analytical tests are generally product-focused, and affective tests are generally consumer-focused. Selection of the appropriate test is critical for actionable results. This review addresses an overview of sensory tests and best practices.

Acids in brewed coffees: Chemical composition and sensory threshold

Coffee brewed on light, and very light-roast coffee beans have emerged as a recent trend among specialty coffee drinkers. The acidity of such light-roast coffee, and coffee in general, is an important sensory characteristic, as there is demonstrated a clear correlation between the roast level and perceived acidity in brewed coffee. The acidity is believed to be strongly linked to the content and composition of organic acids in coffee. Still, there is limited literature on acid content in brewed coffee and on the relevance of specific acid concentrations to sensory perception. In this study, we determined concentrations of acids and sugars in French-press brewed specialty coffee. We used varying roast degrees in the light to very light range using five coffees from different geographical locations (Brazil, Bolivia, and Kenya) and determined the sensory detection threshold and recognition for selected acids. The concentration of all individual acids except one (formic) either significantly decreased (citric, malic, and chlorogenic acid) or increased (acetic, lactic, phosphoric, quinic, and glycolic acid) systematically with an increasing roast degree, while no systematic trends were found between the different coffee samples. The sugar content decreased with an increasing roast degree. The sensory detection threshold for malic, acetic, and lactic acid was determined to be above the actual concentration of said acids in the coffee and just below for phosphoric acid, indicating that these compounds are unlikely to individually be perceived in coffee. Only citric acid can be clearly detected in the threshold test (not identified by experts in coffee) in concentrations above the measured concentrations, as the detection threshold was below (<0.16 g/L) the concentration found in the investigated coffees (0.23-0.60 g/L). The measured citric acid concentration was found to be much higher for the Brazil coffees (0.49 ± 0.08 g/L) compared to the Bolivia coffee (0.40 ± 0.11 g/L), and the Kenya coffees (0.30 ± 0.07 g/L). Furthermore, none of the acids added to the coffee were correctly recognized by coffee experts when spiked with measured average concentrations. Combined, the results question the direct relation between individual organic acids and acidity in coffee and point towards a more complex understanding of perceived acidity.

Umami detection threshold among children of different ethnicities and its correlation with various indices of obesity and blood pressure

Sensitivity to savory taste has been linked to high consumption of savory foods and increased risks of obesity and hypertension. However, there are limited studies that investigate whether obesity indices are correlated with the differences in umami taste perception, particularly in children. This study aimed to investigate the umami detection threshold among children of different ethnicities and the threshold's correlation with obesity indices and blood pressure. A total of 140 subjects were recruited and consisted of a nearly equal distribution of children from three main ethnicities (37.2% Malays, 31.4% Chinese, 31.4% Indians). Umami detection threshold was measured using the two-alternative, forced-choice staircase procedure. Body weight, height, waist circumference and blood pressure of children were measured. Body composition was assessed using bioelectrical impedance analysis (BIA). Mean umami detection threshold was 1.22 ± 1.04 mM and there were no observable differences attributable to the subjects' ethnicities. Body fat percentage was negatively correlated (r = −0.171, p < 0.05), while lean body mass percentage was positively correlated (r = 0.171, p < 0.05) with umami detection threshold. These findings revealed that umami taste perception correlated with children's body composition, but not other anthropometric indicators and blood pressure. Future studies should explore the correlation between umami taste perception and children's total dietary intake.

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The average umami detection threshold of Malaysian children was 1.22 ± 1.04 mM.

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No gender or ethnic differences in umami detection thresholds were observed.

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Umami taste perception was correlated only with children's body composition.

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It is worth to consider umami taste threshold in designing low-sodium food products.

The paired A-Not A design within signal detection theory: Description, differentiation, power analysis and application

Signal detection theory gives a framework for determining how well participants can discriminate between two types of stimuli. This article first examines similarities and differences of forced-choice and A-Not A designs (also known as the yes-no or one-interval). Then it focuses on the latter, in which participants have to classify stimuli, presented to them one at a time, as belonging to one of two possible response categories. The A-Not A task can be, on a first level, replicated or non-replicated, and the sub-design for each can be, on a second level, either a monadic, a mixed, or a paired design. These combinations are explained, and the present article then focuses on the both the non-replicated and replicated paired A-Not A task. Data structure, descriptive statistics, inference statistics, and effect sizes are explained in general and based on example data (Düvel et al., 2020). Documents for the data analysis are given in an extensive online supplement. Furthermore, the important question of statistical power and required sample size is addressed, and several means for the calculation are explained. The authors suggest a standardized procedure for planning, conducting, and evaluating a study employing an A-Not A design.

Children's perceptions of fluid milk with varying levels of milkfat

Schools participating in federal meal programs are limited to serving skim or low-fat (≤1%) flavored and unflavored milk. Few studies have directly addressed child perceptions and preferences for milk containing different amounts of milkfat. The objective of this study was to determine whether children can differentiate between flavored and unflavored fluid milk containing varying levels of milkfat and whether preferences for certain levels of milkfat exist. Flavored and unflavored milks containing 4 different percentages of milkfat (≤0.5, 1, 2, and 3.25%) were high-temperature, short-time processed, filled into half-gallon light-shielded milk jugs, and stored at 4°C in the dark. Milks were evaluated by children (ages 8-13 yr) following 7 d at 4°C. Acceptance testing and tetrad difference testing were conducted on flavored and unflavored milks with and without visual cues to determine if differences were driven by visual or flavor or mouthfeel cues. Child acceptance testing (n = 138 unflavored; n = 123 flavored) was conducted to evaluate liking and perception of selected attributes. Tetrad testing (n = 127 unflavored; n = 129 flavored) was conducted to determine if children could differentiate between different fat levels even in the absence of a difference in acceptance. The experiment was replicated twice. When visual cues were present, children had higher overall liking for 1% and 2% milks than skim for unflavored milk and higher liking for chocolate milks containing at least 1% milk fat than for skim. Differences in liking were driven by appearance, viscosity, and flavor. In the absence of visual cues, no differences were observed in liking or flavor or mouthfeel attributes for unflavored milk but higher liking for at least 1% milk fat in chocolate milk compared with skim was consistent with the presence of visual cues. From tetrad testing, children could visually tell a difference between all unflavored pairs except 2% versus whole milk and could not detect consistent differences between milkfat pairs in the absence of visual cues. For chocolate milk, children could tell a difference between all milk fat pairs with visual cues and could tell a difference between skim versus 2% and skim versus whole milk without visual cues. These results demonstrate that in the absence of package-related flavors, school-age children like unflavored skim milk as well as milk with higher fat content in the absence of visual cues. In contrast, appearance as well as flavor and mouthfeel attributes play a role in children's liking as well as their ability to discriminate between chocolate milks containing different amounts of fat, with chocolate milk containing at least 1% fat preferred. The sensory quality of school lunch milk is vital to child preference, and processing efforts are needed to maximize school milk sensory quality.

Application of tetrad testing to the evaluation of blinding strategies for ancillary supplies used in controlled clinical trials

BACKGROUND/AIMS

Ensuring verum and placebo cannot be visually distinguished from each other is a critical aspect of blinded controlled clinical trials. Our objective was to propose a rational approach to the visual evaluation of placebo matching candidates.

METHODS

Verum and placebo samples were prepared in clear clinical ancillary supplies (intravenous bags, syringes and administration lines) covered at different levels using opaque sleeves. Triangle and tetrad tests, two sensory discriminative testing methods widely used in the food industry, were applied to assess visual differences between verum and placebo.

RESULTS

Triangle and tetrad test results allowed defining the level of opaque coverage required to ensure blinding for three biological drug molecules of therapeutic interest. While the limited number of panelists did not allow a statistically sound comparison of triangle and tetrad test methodologies, tetrad test has a theoretical higher power than triangle test, meaning fewer panelists are needed to reach the same statistical conclusion.

CONCLUSION

Tetrad test offers a rational approach to define a blinding strategy for ancillary supplies used in a controlled clinical trial.

Investigation of human flavor perception and discrimination of the fat content in food using DR A-Not A and 3-AFC methods

This study examined human flavor perception and discrimination of powdered milk samples with various fat contents using two different sensory discrimination methods, DR A-Not A and 3-AFC. DR A-Not A was expected to be more effective. Using skim milk and whole milk powder, five different samples with various fat contents were prepared. An independent samples design was used to compare DR A-Not A and 3-AFC. Each subject performed 24 repeated tests consisting of comparisons of four different test samples from the reference sample. Signal detection d' results showed that sample discrimination was possible using DR A-Not A, but not 3-AFC. Moreover, the just noticeable difference (JND) was calculated using the results of DR A-Not A. The calculated JND was 0.47% (w/v), and the Weber fraction was 0.82. These results confirm that the DR A-Not A method is more effective for studying the human sensitivity to the fat content in food.

Whey Protein Derived Mouthdrying Found to Relate Directly to Retention Post Consumption but Not to Induced Differences in Salivary Flow Rate

Whey protein is fortified into beverages to provide functional benefits, however, these beverages are considered mouthdrying. To date whey protein derived mouthdrying has not been quantified using a 'physical measure' in parallel with rated perception. Saliva flow could also relate to whey protein derived mouthdrying, however this has not been previously tested as an intervention. Accordingly, volunteers (n = 40) tested mouthdrying in different whey beverages and the sensory profile was evaluated by a trained sensory panel (n = 10). Volunteers also rated mouthdrying combined with collection of saliva samples post beverage consumption to measure retention to the oral cavity. To modulate saliva flow rate, volunteers both chewed on parafilm (to increase saliva flow) and used cotton wool (to remove saliva) before tasting beverages and rating mouthdrying. Both the volunteers and sensory panel rated whey protein beverages (WPB) as significantly more mouthdrying than the control beverage (whey permeate). The significantly higher rating of mouthdrying from the volunteers coincided with significantly higher protein concentration in saliva samples post WPB consumption, supporting mucoadhesion as the mechanism. Modulating saliva flow did not lead to any difference in rated mouthdrying and future work would be beneficial to evaluate further the influence of natural variation in salivary flow rate.

Consistent Effects of Whey Protein Fortification on Consumer Perception and Liking of Solid Food Matrices (Cakes and Biscuits) Regardless of Age and Saliva Flow

Although there are numerous high protein products on the market, they are typically not designed with, or for, older consumers. This is surprising considering that dietary guidelines recognise the need for higher protein intake in later life. Protein fortified products are, however, associated with negative sensory attributes and poor consumer acceptance. This paper investigates the extent of mouthdrying sensations within a high protein solid food matrix, along with the effect of age and saliva flow. Solid models using cakes and biscuits, with or without protein fortification, were investigated. The sensory profile and physical properties were analysed and two volunteer studies (n = 84; n = 70) were carried out using two age groups (18–30; 65+). Volunteers rated individual perception and liking of products, and salivary flow rates (mL/min) were measured. Unstimulated salivary flow rates were significantly lower (p < 0.05) in older adults, although this was not found to influence product perception. Protein fortification of cakes and biscuits significantly increased (p < 0.05) perceived mouthdrying, hardness and “off” flavours, and significantly reduced (p < 0.05) melting rate, moistness and liking compared with the control versions. There is a clear need to address negative sensory attributes associated with protein fortification of cakes and biscuits to ensure product suitability for older adults.

Paired preference tests and placebo placement: 1. Should placebo pairs be placed before or after the target pair?

One type of paired preference test uses the 'target' pair of stimuli under consideration to record the measured preferences (prefer A, Prefer B, 'no preference') and a second putatively identical control pair, the 'placebo' pair (AA or BB) to indicate 'false' preferences, unrelated to the target pair, elicited by the effects of the testing situation. From the literature there is disagreement regarding whether it is important to place a placebo pair before or after its corresponding target pair, to elicit a greater proportion of 'no preference' responses. This is important, because the higher the frequency of 'no preference' responses in the placebo pair, the more powerful will be the chi-squared style analysis, which determines whether the target pair displays a significant preference or not. It has been hypothesized that placing the placebo pair after the target pair would elicit more 'no preference' responses in the placebo, because the consumers would have had a chance to experience the difference in sensory characteristics of the two stimuli in the target pair. Using a related samples design, the hypothesis was confirmed although the difference between placebos placed before and after the target was not always significant. It was hypothesized that this lack of significance was caused by greater variance among the items being assessed, making it more difficult to decide whether a putatively placebo pair, in the context of the experiment, was really 'identical'. Psychological adjustments in the consumers were discussed in terms of difference and preference tau criteria. A boost in the proportion of 'no preferences' was observed for the placebo pair built into the triadic preference test, this was explained by the experimenter gaining some control over the consumers' preference tau criteria.

Paired preference tests and placebo placement: 2. Unraveling the effects of stimulus variance

From the literature on paired preference testing, there has been disagreement regarding whether a placebo pair would have a significantly higher frequency of 'no preference' responses if it were to be placed for assessment after its corresponding target pair rather than before. This can be important, because the higher the frequency of 'no preference' responses in the placebo pair, the more powerful will be any chi-squared related analysis, which determines whether the target pair indicates a significant preference or not. In the first paper in this series, it was shown, that indeed a placebo placed after the target pair induced a higher proportion of consumers to respond with a 'no preference'. However, the response was uneven. For some stimuli, the response was strong and significant, for others it was weaker and not significant. It was hypothesized that the weak response could be due to greater variance among the individual stimuli in the placebo sample to be tasted. The effect was confirmed using a priori chosen high and low variance stimuli. Further evidence was obtained from predictions for preference tau criterion levels and frequency of preference changes between two target pairs. All these indicated that the weaker response of some stimuli was due to a higher level of variance among the individual stimuli.

An Investigation of the Influence of Age and Saliva Flow on the Oral Retention of Whey Protein and Its Potential Effect on the Perception and Acceptance of Whey Protein Beverages

Protein fortified products are regularly recommended to older adults to improve nutritional status and limit sarcopenia. However protein fortification can elicit negative sensory attributes such as mouthdrying. Sensitivity to mouthdrying can increase with age, yet the influence of saliva flow and mucoadhesion remain uncertain. Here, two studies tested different whey protein beverages (WPB); 22 healthy younger volunteers completed a pilot and 84 healthy volunteers from two age groups (18-30; 65+) completed the main study. In both studies salivary flow rates (mL/min) were measured and saliva samples were collected at time intervals post beverage consumption to measure mucoadhesion to the oral cavity, where protein concentration was analysed by Bradford Assay. Volunteers rated perception and acceptability of WPBs in the main study. WPB consumption resulted in significantly increased protein concentration (p < 0.0001) in saliva samples compared with a control whey permeate beverage. Older adults had significantly lower unstimulated saliva flow (p = 0.003) and significantly increased protein concentration (p = 0.02) in saliva samples, compared with younger adults. Heating of WPB significantly (p < 0.05) increased mouthdrying and thickness perception and reduced sweetness compared with unheated WPB. Mucoadhesion is concluded to be a true phenomenon in WPBs and increases with age.

The 9-point hedonic scale: Using R-Index Preference Measurement to compute effect size and eliminate artifactual ties

214 consumers used the verbal 9-point hedonic scale to assess 4 types of flavor coated peanuts and 4 types of flavored teas. They used the traditional ANOVA/LSD analysis to provide mean values derived from the 9-point hedonic scale along with measures of significant difference. However, these data did not provide effect sizes. They did not give direct measures of the strength of preference between the various products, which was the main interest. Accordingly, effect sizes were computed. For this, each consumer had also ranked their preferences as they made their ratings on the 9-point hedonic scale. From these, R-Index values were computed to provide the percentages of consumers, who preferred each product to every other product. These direct measures of effect size completed the analysis begun by the ANOVA analysis of the set of mean scores. Also, the measures were nonparametric and avoided issues of the validity of a parametric statistical analysis. They also avoided the problem with the traditional analysis when products in the same scale category are attributed the same scores, when they are not equally liked. Experiment 2, using 207 consumers indicated that this problem was only serious enough to reduce the power of the traditional analysis, compared with the R-Index Preference Measurement, when the number of products being tested approached a dozen say, for product optimization.

Beverage Complexity Yields Unpredicted Power Results for Seven Discrimination Test Methods

The power of discrimination tests is crucial in determining sample size and resources needed for testing. Although research has been conducted on the power analysis of several discrimination testing methods, much of the previous research has focused on basic taste solutions, which may not be directly applicable to food and beverage systems. The objective of the current study was to compare the power of seven discrimination tests: Panelist-Articulated-2-Alternative Forced Choice (PA-2-AFC), triangle, triangle with partial presentation, duo-trio, duo-trio with partial presentation, 4-category rating methods for R-index measure, and same-different pairwise comparison for R-index measure using commercial-type beverage products. Sixty-one prescreened panelists participated in the study. Six product comparisons were performed using tea, tomato juice (three comparisons), citrus-flavored carbonated soda, and cola-flavored carbonated soda. The tests were randomized over two testing sessions for each product comparison. Triangle testing methodologies were found to be overall the most powerful methods across product categories. The PA-2-AFC method was found to be the least powerful across all products. Thurstonian modeling predicts that the PA-2-AFC method would be the most powerful method contrary to the findings of the current study. The products tested were complex in both basic formulations and in changes made between control and variant samples. Complexity of the products may have influenced the discriminability by the panelists using different discrimination tests. Further research should be conducted to characterize the specific influence of sample complexity on the power of discrimination methodology. PRACTICAL APPLICATION: There are several discrimination testing methods that can be selected when determining whether two products are significantly different. A method with high statistical power can allow researchers to save time and resources when addressing this question. The current research compares seven discrimination test methods in order to determine which method results in the highest power for several common commercial-type beverage products. The results from this study demonstrate deviations from Thurstonian model predictions of method power revealing the need to experiment with several methods using commercial-type products commonly tested within a business or research setting prior to selecting an optimal method to use.

Exploring variability in detection thresholds of microparticles through participant characteristics

This study investigated how product familiarity and physiological characteristics of participants affect detectability of microparticles in viscous and semi-solid foods.

Serving Duplicates in a Single Session Can Selectively Improve Sensitivity of Duplicated Intensity Ranking Tests

Duplicating ranking tests can improve the power of preference and sensory intensity tests, and reduce the number of panelists required. With multiple-samples rankings, duplications could be served using different protocols: in two serving sessions (two sample sets, that is, 2SS) to allow a break period or jointly in one serving session (one sample set, that is, 1SS). Evaluating the duplicates in a single session improves statistical data analysis but increases concerns of sensory fatigue, adaptation, memory, and possible irritation. The extent to which each serving protocol for duplicated ranking affects detection of differences has not been reported. This study used panelists (n = 75) who performed both ranking test protocols on two sets of orange juice samples (k = 3). One set was designed to obtain higher similarity than the other set to investigate the effects of degree of difference. Sweetness and yellow color intensity rankings were performed separately for each set to compare the protocols between attributes. The magnitude of the differences was evaluated using Mack-Skillings (M-S) statistics, and the total and individual rank sum differences at varied n (10 to 75) values. With similar set samples, the 2SS serving protocol improved differentiation for yellow color intensity. Although in sweetness, using the 1SS serving protocol showed higher M-S statistics and higher sum of total rank sum differences. Paired comparisons followed the same pattern. With very different samples, both protocols had comparable performance. This study showed that serving duplicates in the 1SS can improve duplicated ranking's power, depending on the task difficulty and attribute, and should be considered before splitting replications into two sessions.

PRACTICAL APPLICATION

This study evaluated two alternative and not previously studied protocols for conducting a duplicated ranking test. One protocol required that each panelist received duplicates in the same single serving session (1SS), against the alternative of serving duplicates separately in two sessions to allow a break period (2SS). Two attributes: yellow color intensity and sweetness intensity of orange juice samples were studied. This study showed that serving duplicates in the same single session can improve duplicated ranking's power, depending on the task difficulty and attribute, and should be considered before splitting replications into two sessions.

Neuromyths in Music Education: Prevalence and Predictors of Misconceptions among Teachers and Students

In the last decade, educational neuroscience has become increasingly important in the context of instruction, and its applications have been transformed into new teaching methods. Although teachers are interested in educational neuroscience, communication between scientists and teachers is not always straightforward. Thus, misunderstandings of neuroscientific research results can evolve into so-called neuromyths. The aim of the present study was to investigate the prevalence of such music-related neuromyths among music teachers and music students. Based on an extensive literature research, 26 theses were compiled and subsequently evaluated by four experts. Fourteen theses were selected, of which seven were designated as scientifically substantiated and seven as scientifically unsubstantiated (hereafter labeled as “neuromyths”). One group of adult music teachers (n = 91) and one group of music education students (n = 125) evaluated the theses (forced-choice discrimination task) in two separate online surveys. Additionally, in both surveys person-characteristic variables were gathered to determine possible predictors for the discrimination performance. As a result, identification rates of the seven scientifically substantiated theses were similar for teachers (76%) and students (78%). Teachers and students correctly rejected 60 and 59%, respectively, of the seven neuromyths as scientifically unsubstantiated statements. Sensitivity analysis by signal detection theory revealed a discrimination performance of d' = 1.25 (SD = 1.12) for the group of teachers and d' = 1.48 (SD = 1.22) for the students. Both groups showed a general tendency to evaluate the theses as scientifically substantiated (teachers: c = −0.35, students: c = −0.41). Specifically, buzz words such as “brain hemisphere” or “cognitive enhancement” were often classified as correct. For the group of teachers, the best predictor of discrimination performance was having read a large number of media about educational neuroscience and related topics (R² = 0.06). For the group of students, the best predictors for discrimination performance were a high number of read media and the hitherto completed number of semesters (R² = 0.14). Our findings make clear that both teachers and students are far from being experts on topics related to educational neuroscience in music and would therefore benefit from current education-related research in psychology and neuroscience.

Replacing the Orchestra? - The Discernibility of Sample Library and Live Orchestra Sounds

Recently, musical sounds from pre-recorded orchestra sample libraries (OSL) have become indispensable in music production for the stage or popular charts. Surprisingly, it is unknown whether human listeners can identify sounds as stemming from real orchestras or OSLs. Thus, an internet-based experiment was conducted to investigate whether a classic orchestral work, produced with sounds from a state-of-the-art OSL, could be reliably discerned from a live orchestra recording of the piece. It could be shown that the entire sample of listeners (N = 602) on average identified the correct sound source at 72.5%. This rate slightly exceeded Alan Turing's well-known upper threshold of 70% for a convincing, simulated performance. However, while sound experts tended to correctly identify the sound source, participants with lower listening expertise, who resembled the majority of music consumers, only achieved 68.6%. As non-expert listeners in the experiment were virtually unable to tell the real-life and OSL sounds apart, it is assumed that OSLs will become more common in music production for economic reasons.

Kinesthetic Force Feedback and Belt Control for the Treadport Locomotion Interface

This paper describes an improved control system for the Treadport immersive locomotion interface, with results that generalize to any treadmill that utilizes an actuated tether to enable self-selected walking speed. A new belt controller is implemented to regulate the user's position; when combined with the user's own volition, this controller also enables the user to naturally self-select their walking speed as they would when walking over ground. A new kinesthetic-force-feedback controller is designed for the tether that applies forces to the user's torso. This new controller is derived based on maintaining the user's sense of balance during belt acceleration, rather than by rendering an inertial force as was done in our prior work. Based on the results of a human-subjects study, the improvements in both controllers significantly contribute to an improved perception of realistic walking on the Treadport. The improved control system uses intuitive dynamic-system and anatomical parameters and requires no ad hoc gain tuning. The control system simply requires three measurements to be made for a given user: the user's mass, the user's height, and the height of the tether attachment point on the user's torso.