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• Psychometric function based on a normal distribution function. • Psychometric function based on a bivariate normal distribution function. • Psychometric function based on a non-central F -distribution function. • Four-interval oddity test is more powerful than the Triangle and Duo-trio tests. • Tables and R codes for data analysis using the four-interval oddity task. The four-interval oddity task is an extension of the Triangle method, which is the three-interval oddity task and is one of the most broadly used conventional sensory discrimination methods. It is a special case of the m - interval oddity task or the m - alternative odd-man-out task where m = 4. It is also a special situation of the unspecified 'M + N' with M = 3 and N = 1. Some new forms of the analytical psychometric function for the four-interval oddity task based on a normal distribution function, a bivariate normal distribution function, and a non-central F -distribution function are provided originally in this paper. The performance of the four-interval oddity task in both difference testing and similarity/equivalence testing is explored and compared with some unspecified forced-choice sensory discrimination methods including the Triangle. Tables and R codes are presented and provided for estimations of the probability of correct response, P c , Thurstonian discriminal distance δ or d´ , and the B value for estimating the variance of d´ for the four-interval oddity task. [ABSTRACT FROM AUTHOR]

A new paradigm of the duo-trio difference-preference (DT-Preference) test was developed as alternatives to the paired-preference test with a no preference option, to correct the overestimation of preference responses. Triadic sample presentation in a preference test elicits odd sample bias, i.e., preferring the sample selected as the same as the reference. In the two replicated DT-Preference test applied for fermented milk product testing using 208 consumers, this psychological bias in preference responses was apparent in the first test. This bias referred to as the tried first reference bias was eliminated by treating those responses that changed depending on which reference was presented as though no preference had been expressed, leading to more reliable sample preferences, meaningful to consumers. The perceptual discriminability in DT-Preference tests was not decreased in comparison to the sole difference tests, while when the preferred sample was used as a reference, the discrimination increased. Practical Applications Consumer acceptance mainly determines the sensory quality of products. Paired-preference test with a no preference option is a broadly used sensory acceptance test method. Yet this preference test method suffers from preference bias caused by the order of sample presentation and/or hidden demand characteristic of the preference test. Such a psychological bias can generate preference responses toward either product presented in a pair for slight or no differences in sample preference, which is not meaningful for consumer behavior. The new paradigm of the duo-trio difference-preference test with a perceptual reference introduced in this article uses another type of psychological bias - odd sample bias - as a means to regulate such biased preferences expressed in a predictable manner. Using this approach, the validity and reliability of preference data analysis can be improved by finding more accurate response proportions of two-way preference responses versus no preference responses. [ABSTRACT FROM AUTHOR]

For the paired difference or preference test applied to consumer research, the 2-Alternative Choice (2-AC) method that allows a "no difference" or "no preference" option is more suitable. For this method, using both test and placebo pairs is seful for estimating the degree of response bias among the consumers using the test and accurately estimating the degree of difference or preference between the test pairs. This paper proposes a Thurstonian model for the 2-AC for both test pairs and placebo pairs in a test method. Maximum likelihood estimations are used for the parameters: d', a perceived distance of difference or preference, and τ, a criterion and a decision parameter. Three methods are used for estimations of the covariance matrix for the parameter estimators: (1) using the built-in functions in the S-Plus and R packages, which are based on maximum likelihood and observed Fisher information; (2) the delta method, which is based on the Taylor series approximation; and (3) the bootstrap method, which is computer-intensive with resampling. Statistical tests are discussed for d' and vectors of responses for test pairs and placebo pairs in both a monadic design and a paired design. R/S-Plus codes are developed and provided for the calculations. [ABSTRACT FROM AUTHOR]

Psychometric functions for discrimination tests, which connect probabilities of correct response, pc, with Thurstonian discriminal distances, d′, are of theoretical and practical significance. This paper uses a computer-intensive approach to produce simulation-derived psychometric functions for the ' M + N' test, which is a generalization and can be considered as a framework of many forced-choice methods. The paper demonstrates and describes chance probabilities in different situations for the ' M + N' test. The paper compares the performances of the specified and unspecified ' M + N' test with the M = N test. The paper provides novel tables for pc and d′ for four specific versions of the ' M + N' test: the specified 'two-out-of-five' test (i.e., the ' M + N' test with M = 3 and N = 2); the unspecified 'one-out-of-four' test (i.e., the ' M + N' test with M = 3 and N = 1); the specified and unspecified octad tests (i.e., the ' M + N' test with M = N = 4). The corresponding B values, for calculation of the variances of d' for the tests, are also provided. The concept and practice of pseudo-correct response, i.e., forgiveness introduced by Ennis, are discussed and generalized. Practical Applications Considering the constraints imposed by the products and the circumstances of the business objective, different forms of various difference test method might be selected as the most suitable design. The proposed Thurstonian modeling approach using a simulation-derived psychometric function makes it possible to drive psychometric functions for any one of the more than 40 different versions of the ' M + N' test. This paper shows that a simulation-derived psychometric function is compatible with an exact psychometric function. R/ S-Plus codes for the simulation-derived psychometric functions are also developed and provided. Using this technique, various versions of commonly used sensory difference test methods, including the 2- AFC, triangle and tetrad, can be compared with many more versions of difference test methods. In addition, using the supplied R/ S-Plus codes, the Thurstonian sensory difference measure, d′, can be computed easily and quickly for various forms of the ' M + N' test. [ABSTRACT FROM AUTHOR]

• An analytical psychometric function for the dual reference duo-trio (DRDT). • Two forms of the analytical psychometric function for the DRDT. • Tables and R codes for P c , d ' , and variance of d ' (B value) based on the function. The dual reference duo-trio (DRDT) is an improved balanced-reference duo-trio method, in which two same references are presented in a test but the reference is changed across the tests. The performance of the DRDT has been investigated theoretically based on a simulation-derived psychometric function in a previous paper published in this journal. The DRDT method is more powerful than the conventional duo-trio and the triangle methods. This paper derives an analytical psychometric function for the DRDT. Another form of the psychometric function for the DRDT is also derived based on the Torgerson's method of triads. Tables and R codes are provided for presentations and calculations of P c , δ (or d '), and variance of d ' (B -value) based on the analytical psychometric function for the method. [ABSTRACT FROM AUTHOR]

Ratings are widely and frequently used in sensory analysis. However, ratings from different methods cannot be treated equivalently because they represent different types of data generated from different cognitive mechanisms. Ignoring this fact may lead to misleading conclusions about true sensory difference or treatment effects obtained from the ratings data analysis. The receiver operating characteristic ( ROC) curve in signal detection theory is used in this paper to model the ratings of the A- Not A and the same-different methods. This paper comprehensively discusses statistical analysis of the ROC curves for the methods, including presentations of the ROC curve functions, estimations of d′s and their variances, goodness-of-fit tests, difference and similarity tests, testing powers and sample sizes, etc. The paper also discusses alternative indices of sensory difference derived from the ROC curve, including the R-index and Gini index. It is appealing to rethink the significance of the R-index, not only as a powerful test statistic but also as a useful sensory measure. R functions are provided for implementing all the analyses discussed in the paper. Practical Applications This paper provides a variety of approaches and R functions for statistical analysis for the ratings of the A- Not A, and the ratings of the same-different methods. The measures of d′s and other indices, which are method-independent measures of sensory differences and treatment effects, can be estimated from different types of ratings data. [ABSTRACT FROM AUTHOR]

Abstract: The effects of reference schemes (reference mode – constant vs. balanced-, number, position, and nature – stronger vs. weaker) on the performance of replicated duo-trio tests were investigated using four versions of duo-trio protocols (DTF, DTM, DTFR, and DTFM), using two different pairs of tomato juices with different sodium content. Examination of proportion of correct answers (Pc) and d′ estimates indicated that when the cognitive strategy was fixed to the comparison of distances (COD) strategy, the constant-reference mode showed the superior test performance over the balanced-reference mode, only for DTFM performed using the stronger reference. Among the tests with the balanced-reference mode, for DTF, estimates of d′ of the tests using the stronger-reference (W-odd) were significantly higher than tests using the weaker-reference (S-odd), whereas the opposite was true for DTM, revealing the operational influence of the reference position. In general, the DTF or DTFM using the stronger (saltier) product as a constant-reference is recommended as an operationally more powerful protocol to discriminate products having high sodium contents. [Copyright &y& Elsevier]

Abstract: The 2-AC protocol is a 2-AFC protocol with a “no-difference” option and is technically identical to the paired preference test with a “no-preference” option. The Thurstonian model for the 2-AC protocol is parameterized by δ and a decision parameter τ, the estimates of which can be obtained by fairly simple well-known methods. In this paper we describe how standard errors of the parameters can be obtained and how exact power computations can be performed. We also show how the Thurstonian model for the 2-AC protocol is closely related to a statistical model known as a cumulative probit model. This relationship makes it possible to extract estimates and standard errors of δ and τ from general statistical software, and furthermore, it makes it possible to combine standard regression modelling with the Thurstonian model for the 2-AC protocol. A model for replicated 2-AC data is proposed using cumulative link mixed models. Examples will be given throughout the paper and the methodology is implemented in the authors’ free R-packages sensR and ordinal. [Copyright &y& Elsevier]

Besides responses to the target pair of stimuli being tested in a paired preference test, comparison with responses to a putatively identical "placebo" pair can be used for a test of significance, to determine whether the response frequencies elicited by the target pair are different from those that would be obtained had there been no preference. Yet, preference responses elicited by the placebo pair can also be used as a way of identifying consumers who bias avoided the "No preference" option and thus generated biased response. Such consumers can then be eliminated. Yet, using this approach greatly reduces the sample size. However, using some response options associated with purchase intent rather than liking can reduce the number of consumers that are eliminated. This was confirmed for potato chip, milk and orange juice stimuli. From psychology, the concepts of operational preference and types of response bias appropriate to preference testing were introduced and discussed. PRACTICAL APPLICATIONS: The measurement of preference and acceptance of foods is important for product development and decisions regarding the launching of new products into the market. The paired preference test has some issues associated with its design and analysis, and these must be considered if preference tests are to give valid and reliable data. One of the problems is that the majority of consumers tend to report preferences even when the stimuli are putatively identical; here, a "No preference" response would seem more appropriate. Such consumers would seem to be reacting to the extraneous conditions of the preference test rather than the sensory characteristics of the putatively identical stimuli under consideration. Such responses could be termed "biased response." Yet, the consumers' responses to the target (different) stimuli under consideration could be trusted more if the consumers had shown that they did not have this tendency to give "biased responses." They would show this by selecting a "No preference" response to putatively identical stimuli. This paper shows that the tendency to give "biased response" can be reduced by manipulating the wording of the preference question. This does not furnish a complete solution to the problem but it indicates one possible step toward solution and adds valuable information to the body of knowledge that is being built with a view avoiding the difficulties associated with preference testing. [ABSTRACT FROM AUTHOR]

The four-alternative forced choice (4-AFC) is one of a family of m-AFC tests used in Psychology. Based on a detection-theoretic model, for a given d′ it is slightly more powerful than the 3-AFC and 2-AFC. Although its potential use in sensory food science is limited, there are occasions when it will be used. Accordingly, tables of d′ values for given proportions of correct responses (pc) along with corresponding values of B, for computing variances, are given in this paper. Power comparisons are also made between 2-AFC, 3-AFC and 4-AFC tests. PRACTICAL APPLICATIONS For sensory difference testing, the choice of test will depend on several factors such as statistical power as well as various physiological and cognitive effects. Because of the wide variation in the sensory effects that food and personal product stimuli can have on judges, it is important to have a wide variety of test methods available. Therefore, even less common tests need to be considered. The 4-AFC can be used on occasions and it is certainly suitable for visual judgments. Accordingly, for this method, it is appropriate to have tables of d′ and B for computing variances. [ABSTRACT FROM AUTHOR]

Preference tests were performed for varieties of potato chips, orange juices and chocolate chip cookies using three response protocols: the traditional paired preference test with the “no preference” option, a 9-point hedonic scale and a 6-point hybrid hedonic/purchase intent scale. The different stimuli to be assessed were presented in pairs, but putatively identical stimuli were also presented as a “placebo” pair. Performance on the placebo pair with identical stimuli provided a measure of the hidden demand characteristics of the test protocol. The presentation of the different pairs provided a measure of preference accompanied by such hidden demand effects. Comparison between the two allowed a better measure of preference per se. The order of presentation of the identical and different pairs did show occasional slight evidence of contrast effects. For the placebo “identical” pairs, a majority of consumers reported false preferences. Liking questions with the hedonic and hybrid scales elicited fewer false preferences than preference questions with the paired preference protocol. Yet, the effects tended to be slight. The 6-point hedonic/purchase intent scale exhibited the fewest false preferences in the placebo condition, and this was because of its fewer categories rather than any cognitive strategy change elicited by its different labels. PRACTICAL APPLICATIONS A problem with paired preference testing is the tendency of consumers to give false preferences, which produces the seriously misleadingoverestimation of the proportion of consumers who have preferences for one or other of the products being assessed. The placebo condition is an important control for alleviating this problem. The statistical analysis can be improved by finding a protocol that maximizes the proportion of “no preference” responses in the placebo condition. The key finding here is that using hedonic or purchase intent questions rather than preference questions may possibly provide a way of achieving this aim. [ABSTRACT FROM AUTHOR]

Abstract: The duo–trio test is a simple non-directional difference test method suitable for discriminating subtle differences between confusable stimuli. It is suitable for consumers as well as trained panelists. In the present study, the influence of memory and tasting sequence in the duo–trio was investigated, using various low concentrations of NaCl in a roving discrimination design. Three versions of duo–trio protocols were considered. The first protocol was the traditional duo–trio with the reference tasted first (DTF). The second protocol was the duo–trio with the reference tasted in the middle, between the two test samples (DTM). The third protocol was the duo–trio with the reference tasted twice, first and last as a reminder (DTFR). In some conditions, the higher concentration of NaCl solution was the reference (W-odd); in others, the lower concentration was the reference stimulus (S-odd). Calculated d′ values indicated a superior performance for the DTFR over the DTF and DTM. In the DTF, S-odd yielded a lower d′ than W-odd, probably due to NaCl taste adaptation. In the DTFR, the effects of adaptation were counterbalanced for all the stimuli including the reference, resulting in no significant sequence effect. In the DTM, the sequence of the first two stimuli in the test had a significant effect on the performance, probably due to the decision strategy used for the protocol. Manipulation of the reference in the duo–trio test introduces issues such as attention as well as memory and adaptation. [Copyright &y& Elsevier]

Abstract: For sensory difference tests, one way, but not the only way, of dealing with the problem of overdispersion is to use a beta-binomial analysis. Commonly, binomial statistical analyses are used for these methods and they assume that the sensitivity of the judges is uniform. However, judge sensitivity varies and this adds a problematical extra variance to the distribution. This is termed overdispersion and renders simple binomial analysis prone to Type I error. The distribution of sensitivity of the judges is described by a beta-distribution. The analysis, combining beta and binomial distributions, gives an index, gamma. This ranges from zero, for no overdispersion, to unity, for total overdispersion. A compact beta-distribution clustered around the mean of the binomial distribution, would add little extra variance and elicit minimum distortion of the binomial distribution, yielding a zero or near zero gamma value. A more scattered or even bimodal beta-distribution would have a substantial effect and yield a significant gamma value. One question that has been posed is whether some test methods are more prone to overdispersion than others. Yet, a consideration of the reasons for overdispersion would suggest that significant gamma values were more a result of obtaining a heterogenous sample of sensitive and insensitive judges by chance. To confirm this, ‘less sensitive’ and ‘more sensitive’ samples of judges performed 2-AFC and 3-AFC tests with resulting zero gamma values, indicating no overdispersion. However, when the less and more sensitive groups were combined, significant gamma values were obtained, indicating the presence of overdispersion. However, in a further experiment using 2-AFC tests, when the ‘less sensitive’ group had its sensitivity increased by a ‘warm-up’ procedure, combination with the ‘more sensitive’ group did not result in overdispersion. [Copyright &y& Elsevier]

• The d′ A expectation profile effectively quantified consumer-expected attributes. • The d′ A expectation profile pinpointed key attributes for overall satisfaction. • Satisfaction drivers were identified from PLSR and LSA using product sensory tests. • The d′ A expectation profile provided better optimization insights than PLSR or LSA. • Expected profile valence can be customized for target consumers. Understanding consumer requirements with respect to the sensory attributes of food and the sentimental consequences is critical for enhancing consumer satisfaction and achieving market success. A recent innovation, the signal detection expectation profiling method, introduced by Lee, Kim, van Hout, and Lee (2021) , utilizes the two-step rating-based 'double-faced applicability (DFA)' test to create expectation profiles for product attributes, quantified by d′ A output measures. This study aimed to demonstrate and test the usage and efficacy of the d′ A expectation profiling method to provide insight for product development. The efficiency of this approach for using a two-step rating-based DFA was examined first and the information guided by the d′ A expectation profiling output measures was compared to satisfaction drivers identified through partial least square (PLS) regression and landscape segmentation analysis (LSA), commonly used to link consumer satisfaction/liking and sensory perception. Consumer expectations and satisfaction/sensory evaluations of six different mayonnaise products formed the dataset. Overall, the d′ A expectation profiles effectively identified the key attributes significantly impacting overall satisfaction, aligning with the results of the PLS regression and LSA. The advantage of d′ A expectation profiles lies in their quantitative representation of the degree of expected sensory attributes, extending beyond the scope of actual evaluated products and offering actionable insights for product optimization. Furthermore, by incorporating custom attributes (descriptor pairs) based on the hedonic valence of target consumers, the d′ A expectation profile showcases the potential for effectively addressing consumer-relevant attributes tailored to specific target consumer groups. [ABSTRACT FROM AUTHOR]

• Three perceptual dimensions were studied with the double-faced applicability(DFA) test. • They showed no correlation with each other, indicating their independence. • They correlated to corresponding individual attributes and contributed to satisfaction. • Dimensions outperformed individual attributes for product discrimination sensitivity. • DFA tests with tailored three dimensions can speed up product characterizations. In the food/beverage industry, rapidly discerning product characteristics based on consumer perception and satisfaction is essential. This requires using key consumer perceptual dimensions, rather than numerous sensory attributes, to swiftly and precisely characterize products. In a previous study by Lee, Kim, and Lee (2023), a two-step rating-based 'double-faced applicability' (DFA) test and signal detection analyses of affective magnitude (d' A) were applied to assess consumer perceptions of ready-to-drink (RTD) lattes. This research identified three consumer perceptual dimensions across eighteen sensory attributes, which were suggested to be directly linked to RTD latte quality and, consequently, to consumer sensory satisfaction/liking. The objective of the present study was to validate these three perceptual dimensions characterizing the perception of RTD lattes and their relationships with sensory satisfaction. To achieve this, a comparative experiment was conducted using the DFA test and d' A analysis to evaluate consumer perceptions of the identical RTD lattes as in the previous study but with a different consumer group. In this experiment, only three consumer perception attributes reflecting the three dimensions were employed in the DFA tests to compare product characterization and discrimination results with the previous study using eighteen attribute pairs. Additionally, consumer satisfaction with the products was also studied. The results confirmed the distinctiveness of these three dimensions and their association with corresponding sensory attributes and overall satisfaction. The superior product discrimination further validates its effectiveness, highlighting the potential of such a three-dimensional perceptual model and d' A analysis as a rapid and effective method for understanding product characteristics to meet consumer satisfaction. [ABSTRACT FROM AUTHOR]

Recently, we have proposed the degree of satisfaction-difference (DOSD) method to measure changes in consumer product acceptance (Kim, van Hout, Dessirier, et al., 2018). The DOSD method utilizes A-Not A with reminder format to improve the stability and validity of the consumer evaluation by reminding consumers of the evaluative criteria with the reference sampling and by controlling the sequence effects on each sampling of the blind test product. Using the data obtained from DOSD method, in this paper, a way to compute a measure of the absolute degree of satisfaction for a product based on signal detection theory (SDT), referred to as d' SAT (d-prime satisfaction), is suggested. This new measure is compared to the comparative distance measure of d' , the degree of satisfaction difference of a product from the reference product, which has been already described in the previous study. The absolute satisfaction degree is a value indicating each product’s degree of consumer satisfaction as in the hedonic score. However, the degree of satisfaction measure presented herein is superior to the hedonic score because it enables easy interpretation of whether a group of consumers are satisfied or not with a product. In practical situations, the two measures of the degree of satisfaction difference from the reference and the degree of satisfaction, which are computed using the data from DOSD method, can be used complementarily in order to reveal information about consumer perception and evaluation. [ABSTRACT FROM AUTHOR]

In the fast moving consumer goods industry, measuring consumer acceptance toward products is crucial for product development and marketing. Consumers are generally considered hedonists and, thus momentary hedonic scores are assumed to represent consumer acceptance. Yet for many product types, such as household care products, consumers might be considered utilitarian and their usage experience with the product might be equally important for consumer acceptance. To quantify consumer holistic product usage experience, a two-step signal detection rating-based satisfaction measure was used such that an independent signal detection theory index termed d' A (d-prime affect magnitude) could be computed for each product to represent consumer satisfaction with the usage experience and with the product itself. The objective of the present study was to investigate the effect of simultaneous attribute evaluation using the ‘double-faced applicability’ (DFA) test on product discrimination of this satisfaction measure. The conventional 10-point hedonic ratings with and without the DFA test were used as control methods for comparison. Results showed that significant product discriminations were observed only in the group who performed the satisfaction measure with the DFA test. Also, significant discriminations in quality attributes of the DFA test questionnaire were more frequently observed in the group that performed the satisfaction test than in those who performed the hedonic test. These results indicate that compared to using hedonic scores, the satisfaction test with the DFA has the potential to improve research on the quality predictors of household products. [ABSTRACT FROM AUTHOR]

Descriptive analysis with a trained sensory panel has thus far been the most well defined methodology to characterize various products. However, in practical terms, intensive training in descriptive analysis has been recognized as a serious defect. To overcome this limitation, various novel rapid sensory profiling methodologies have been suggested in the literature. Among these, attribute-based methodologies such as check-all-that-apply (CATA) questions showed results comparable to those of conventional sensory descriptive analysis. Kim, Hopkinson, van Hout, and Lee (2017a, 2017b) have proposed a novel attribute-based methodology termed the two-step rating-based ‘double-faced applicability’ test with a novel output measure of applicability magnitude ( d' A ) for measuring consumers' product usage experience throughout various product usage stages. In this paper, the potential of the two-step rating-based ‘double-faced applicability’ test with d' A was investigated as an alternative to conventional sensory descriptive analysis in terms of sensory characterization and product discrimination. Twelve commercial spread products were evaluated using both conventional sensory descriptive analysis with a trained sensory panel and two-step rating-based ‘double-faced applicability’ test with an untrained sensory panel. The results demonstrated that the ‘double-faced applicability’ test can be used to provide a direct measure of the applicability magnitude of sensory attributes of the samples tested in terms of d' A for sensory characterization of individual samples and multiple sample comparisons. This suggests that when the appropriate list of attributes to be used in the questionnaire is already available, the two-step rating-based ‘double-faced applicability’ test with d' A can be used as a more efficient alternative to conventional descriptive analysis, without requiring any intensive training process. [ABSTRACT FROM AUTHOR]

This paper proposes a new type of sensory discrimination methods, i.e., paired versions of various sensory discrimination forced-choice methods, which can be regarded as modified versions of the same-different method. The new type of methods possesses the advantage of the same-different test for measuring overall sensory difference, but overcomes its weaknesses of large variations of response bias and lower testing power. An important finding is that this type of methods is closely related to the same-different area theorem and its extension. The same-different area theorem establishes an equivalence between the area under the receiver operating characteristic (ROC) curve of the same-different method and the proportion of correct responses ( P c ) in the dual-pair method. This paper re-demonstrates and extends the same-different area theorem. An analytical expression of a general psychometric function for the new type of methods is derived. Performances of the new type of methods are evaluated with testing power and sample size in both difference and similarity/equivalence tests. R codes are provided for the new type of methods for P c , Thurstonian discriminal distance δ, and variance of d′ , where d′ is an estimator of δ. [ABSTRACT FROM AUTHOR]

• Two attribute-based consumer perception study methods compared: DFA test vs CATA. • d′ A of DFA had better sample discriminability than the citation frequency of CATA. • d′ A of DFA gave sample characterization similar to the citation frequency of CATA. • d′ A reflected positive, negative, or neutral group mean valence of each attribute. • d′ A was better interpretable: a sigmoid relationship with the citation frequency. For successful product development and marketing in the food/beverage industry, it is vital to study the product attributes perceived by consumers effectively and efficiently. Recently, a two-step rating-based 'double-faced applicability' (DFA) test was developed to study consumer perception and evaluation of product attributes in a quantitative way using d-prime affect magnitude (d' A) based on signal detection theory. This study assessed the product discrimination and characterization performance and interpretationability of d' A output measures of the DFA approach in comparison with the check-all-that-apply (CATA) question. An independent samples design (each N = 108) was used to evaluate eighteen ready-to-drink (RTD) latte products with eighteen attributes. A cluster analysis was also performed, and based on this the relationships of the two output statistics - d' A and total citation frequency were examined. Product attributes were generated based on literature reviews on coffee sensory and emotion studies and sensory/consumer research methodology to encompass consumer perception generally applicable to beverage, and for each attribute, a pair of 'double-faced' descriptors in three categories - 'general weak-strong', 'sensory', and 'sentimental consequence' were used for the DFA test. The d' A of the DFA test provided similar product characterization to citation frequency of the CATA question, yet provided better product discrimination and reflected the consumer affective perception for each product independently in a better interpretable way, in valence. It showed a sigmoid relationship with the citation frequency due to its nature of reflecting valence. Overall, the results contribute support for the usefulness of the DFA approach for consumer product testing and suggest the potential of developing a generally applicable DFA test format for studying integrated attribute perception. [ABSTRACT FROM AUTHOR]

• The effects of equal RPP (0.5 RPP) in the A-Not A and A-Not AR ratings were studied. • When not informed, 0.5 RPP was superior to 0.25 RPP for both test designs. • The effects were lower in the A-Not AR ratings, showing the effects of reminders. • When informed of 0.5 RPP, sensory panels' response behavior changed. • Yet, such change lowered discrimination of small differences for A-Not AR ratings. Sensory discrimination analysis based on signal detection theory (SDT) deals with measuring small sensory differences between samples required for various business objectives, including quality control, reformulation, cost reduction, and product development. Variants of the A-Not A test designs have been used for SDT analysis using sensory panels to measure the sensory differences between a reference and multiple test products because they are economical and sensitive for such multiple product comparisons. On the other hand, the test protocols of conducting the A-Not A ratings affect the test performance and data quality. The present study examined the effects of equal sample presentation probability between reference vs test samples (0.5 reference presentation probability, 0.5 RPP) with and without informing a panel of RPP on the test performance of A-Not A and A-Not AR ratings using a reference with three test products. SDT analyses including the novel d' Rec analysis were used to examine these effects. The overall experiment consisted of three protocols: Control – 0.25 RPP without informing; Modified-1 protocol – 0.5 RPP without informing; Modified-2 protocol – 0.5 RPP with informing of the RPP. Compared to the Control, the Modified-1 protocol employing 0.5 RPP without informing improved discrimination performance significantly (higher d′ values) for the A-Not A ratings. Compared with the A-Not A ratings, the effects of the Modified-1 protocol were reduced for the A-Not AR ratings, showing the effects of reminders assisting the evaluations. The test instructions providing information of 0.5 RPP were inefficient. It shifted the panel's middle decision criteria (c 0) close to zero but did not improve the discrimination performance better than the Control. Overall, the efficiency of 0.5 RPP was confirmed using sensory panels for both A-Not A and A-Not A ratings, and it was shown that the novel d' Rec analysis is an efficient way to study the reasons for changes in a panel's performance and diagnose the sensory data quality obtained from sensory panels. [ABSTRACT FROM AUTHOR]

• The A-Not AR protocols studied over 2 days by discrimination d′ and recognition d′ (d′ Rec.). • Protocols had different FP and RPP with three test products and a reference. • A pre-test and the control protocol with FP of reference tastings and 0.25 RPP used as a comparison. • FP of a specified tetrad or 2-AFCR test with 0.5 RPP had higher d′ and d′ Rec values. • Significant learning over 2 days was found only in 2-AFCR FP with 0.5 RPP. The A-Not A with reminder (A-Not AR) test using a two-step rating is an efficient method for measuring the overall sensory differences between multiple products and a reference product. An efficient reference-familiarization procedure and a test protocol that helps the subjects to adopt stable decision criteria are essential for using the A-Not AR test using a two-step rating based on a pooling approach and analyzing the pooled data from different sessions effectively. Two experimental factors for improving the A-Not AR test performance, the familiarization procedure (FP) and reference presentation probability (RPP), were examined using three test protocols following the same pre-test utilizing unspecified tetrad tests. In the Control protocol, the reference was tasted twice as the FP and the RPP was 0.25 with three test products included. In the two Modified protocols, either specified tetrad tests or 2-AFCR tests were used as the FP, both with feedback and re-tasting, and the RPP was 0.5. An independent samples design using three groups (each N = 40) having equal sensitivity was used to test the efficiency of the test protocols over two days. The three groups were formed based on the results of the pre-test. The results of discrimination d' and recognition index d' Rec analyses confirmed that the Modified protocols led to superior test results; the specified tetrad FP was optimal for one-day testing, while the 2-AFCR FP was optimal for repeated testing. Further research will be needed to examine the effects of such comparative task-type FP and 0.5 RPP on the test stability over repetitions and the reliability with different product ranges and different types of pre-test. [ABSTRACT FROM AUTHOR]

As reformulations and processing changes are increasingly needed in the food industry to produce healthier, more sustainable, and cost effective products while maintaining superior quality, reliable measurements of consumers' sensory perception and discrimination are becoming more critical. Consumer discrimination methods using a preferred-reference duo–trio test design have been shown to be effective in improving the discrimination performance by customizing sample presentation sequences. However, this design can add complexity to the discrimination task for some consumers, resulting in more errors in sensory discrimination. The objective of the present study was to investigate the effects of different types of test instructions using the preference-reference duo–trio test design where a paired-preference test is followed by 6 repeated preferred-reference duo–trio tests, in comparison to the analytical method using the balanced-reference duo–trio. Analyses of d' estimates (product-related measure) and probabilistic sensory discriminators in momentary numbers of subjects showing statistical significance (subject-related measure) revealed that only preferred-reference duo–trio test using affective reference-framing, either by providing no information about the reference or information on a previously preferred sample, improved the sensory discrimination more than the analytical method. No decrease in discrimination performance was observed with any type of instruction, confirming that consumers could handle the test methods. These results suggest that when repeated tests are feasible, using the affective discrimination method would be operationally more efficient as well as ecologically more reliable for measuring consumers' sensory discrimination ability. [ABSTRACT FROM AUTHOR]

The balanced-reference duo-trio test using the comparison of distances (COD) strategy is a widely used unspecified discrimination method. However, it suffers lower testing power. A dual reference duo-trio (DRDT) method was proposed recently as an improved duo-trio in the sensory literature. This paper proposes a new cognitive decision strategy for the DRDT, involving the comparison of pairs of distances (COPD) and investigates theoretically the performance of the DRDT based on a simulation-derived psychometric function. The DRDT is compared with the conventional balanced-reference duo-trio (DT) and the triangle methods. Comparison results show that the DRDT assuming the COPD is more sensitive than the conventional DT assuming the COD, and is more powerful than the conventional DT and the triangle methods for both difference testing and similarity/equivalence testing. The averaged generalized power efficiency of the DRDT is about 34% over that of the conventional DT, and is about 13% over that of the triangle method. [ABSTRACT FROM AUTHOR]

Using signal detection theory (SDT) and Thurstonian analysis, it has been possible in the food industry to make various business decisions such as reformulations and cost reductions based on the degree of consumer sensory discriminability by applying equivalence/difference testing. To achieve more efficient decision-making, it is important to investigate a theoretically and operationally more powerful consumer discrimination test method. Cognitive decision strategies used in discrimination methods largely determine relative test power and thus are of theoretical and practical significance. The goal of this study was to investigate if test procedures using a constant-ref. duo–trio design enable untrained/naïve subjects to use a powerful 2-AFC strategy. Although previously the constant-ref. duo–trio design showed operational superiority to other unspecified test methods, the ‘comparison of distance’ (COD) strategy which is conventionally assumed for the duo–trio, lacks theorized power. The tested variables included two versions of duo–trio design, different familiarizations, instructions and experimental session designs. Three different iced tea samples were discriminated from a reference by 263 untrained/naïve subjects using 5 different duo–trio test procedures. Results showed that untrained/naïve subjects were able to perform the duo–trio with the reference presented twice, first and middle (DTFM) as a 2-AFC procedure, even with multiple pairs in a block design, after only two reference tastings with the information of the constant-reference. The duo–trio preceded by specified tetrad tests also showed potential as another efficient two-sequence test design. These results suggest that such constant-ref. duo–trio protocols using a 2-AFC strategy can be an alternative to the unspecified triangle and tetrad test. [ABSTRACT FROM AUTHOR]

Determining critical attributes associated with consumer perceived benefit and choice is essential for the fast moving consumer goods industry. The goals of the present study were to develop a lexicon specific to usage process for kitchen cleansers using a novel consumer test and to test usage stage-dependency of the lexicon. Holistic usage process of kitchen cleansers was classified into purchase moment, during use and completion point. For a series of projective interviews, a semantic/language library, a collection of attributes relevant to kitchen cleansers was used as response options. Ethnographic observations/interviews were also incorporated into the consumer test to evoke consumers' natural usage process. Comparisons of the developed lexicon revealed differences of consumers' evaluation processes across different usage stages. At the purchase moment, attributes associated with Convenience and Functionality categories were found to be more important, whereas at completion point, attributes associated with Sensory Quality and Sentimental Consequence were more important. [ABSTRACT FROM AUTHOR]

To achieve more efficient decision making for many business objectives including reformulations and processing changes in the food industry, the important questions become 1) what is the best way to measure consumer discrimination and 2) how much discrimination is meaningful in consumer preference that can be used as a business action standard for food quality maintenance. The purpose of the present paper was to develop a consumer sensory discrimination methodology using affective reference framing to provide more accurate information on both questions. For such affective methods, two versions of repeated duo–trio tests using the preferred sample as reference were implemented: Affective group I—each of 8 repeated duo–trio tests was preceded by a paired-preference test; and Affective group II—a paired-preference test was performed before each of the two sub-sessions consisted of 6 repeated duo–trio tests and the preferred sample was used as a constant-reference during the sub-session. The discrimination performance of these tests was compared to the analytical balanced-reference duo–trio test. Results indicated that for affective group I only, it was possible to identify the ‘affective discriminators’ who showed genuine preference for one product over another and their sensory discrimination in the affective method was significantly higher than in the analytical method. It suggested that this affective method is a desirable consumer sensory methodology that can reveal insightful consumer-relevant sensory differences by comparing sensory discriminations between the so-called ‘affective discriminators’ and ‘affective non-discriminators’. [ABSTRACT FROM AUTHOR]

The A- Not A with reminder ( A- Not AR) is a relatively new method in the sensory literature. This paper derives and demonstrates the function illustrating the relationship between the area under the receiver operating characteristic ( ROC) curve and d′ for the A- Not AR with the differencing strategy. This function shows that the area under an ROC curve for the A- Not AR is equal to the maximum proportion of correct responses in an A- Not A. This theoretic function can be used to estimate d′ and its variance from the ratings of the A- Not AR. A simulation study shows that the nonparametric estimation based on this function is close to those obtained by using the maximum likelihood estimation. The estimation of the variance of d′ based on the delta method is close to that obtained by using the bootstrap method. R codes are provided for the estimations of d′ and its variance as well as simulations. Practical Applications The A- Not AR is a variation of the conventional A- Not A method, which is used in the sensory field for discrimination testing. This method is particularly useful when it is difficult to have an adequate familiarization procedure for the test samples for panelists before a test. This approach also offers the potential for applying such a method to problems like hedonic, purchase intent, and consumer concept measures in addition to other measures in the sensory and consumer science field. This paper provides a new nonparametric method and R codes for estimating d′ and its variance from the ratings of the A- Not AR. [ABSTRACT FROM AUTHOR]

ABSTRACT To investigate more flexible methods for measuring overall sensory differences, the performance of three nonattribute-specified difference test methods was compared using Signal Detection Theory. A-Not A, 2-AFC, and 2-AFCR tests were performed with experienced subjects over repeated sessions. Learning effects were investigated to determine how much training would be needed before subjects could perform these tests consistently. Results in d′ showed that in early sessions, the 2-AFC and 2-AFCR performed better (higher d′) than A-Not A and that after two sessions, the test performance stabilized on that level. Learning effects for the A-Not A test were poorer in the earlier sessions, with performance levels increasing, even after six sessions. In business situations where the tested products frequently vary, the use of 2-AFC and 2-AFCR would be recommended because they are more sensitive in the earlier sessions, requiring less training time than A-Not A. PRACTICAL APPLICATIONS Sensory difference tests are important tools for business decision making. Food companies may save a lot of money by employing more effective methodologies. For sensory difference tests to be used accurately and efficiently, test performances need to be investigated with consideration for food discrimination constraints and objectives. This article explored the performance of nonattribute-specified 2-AFC and 2-AFCR tests over several sessions in comparison to the results of a standard signal detection measure, A-Not A, to use the differences between these methods as a basis for inference concerning the cognitive strategies and relative test effectiveness of nonattribute-specified 2-AFC and 2-AFCR for food discrimination, in practical situations when both the reference product and test product(s) change frequently. This article suggested the applicability of a nonattribute-specified 2-AFCR procedure for discriminating small differences without much prior training. [ABSTRACT FROM AUTHOR]

Abstract: The effects of the number and position of the reference stimulus given in the duo-trio test were investigated using tomato juice with various salt concentrations in a roving discrimination design. Estimates of d′ indicated a superior performance of the duo-trio when the reference was tasted twice, first and last as a reminder (DTFR), when compared with the results of the traditional duo-trio (DTF) and the duo-trio with the reference tasted in the middle (DTM). In the DTFR and DTM, the sequence of the last two stimuli in the test had a significant effect on performance, probably due to its aid in identifying the sensory dimension of difference. Comparison of the performance of the DTF and DTM tests for sequences having the same ordering (WWS or SSW) revealed that d′ estimates tended to be higher for the DTF, despite the suggestion that the memory requirement is reduced in the DTM. These results were explained successfully by the Sequential Perception Analysis (SPA) model. [Copyright &y& Elsevier]

Abstract: Affective and analytical same-different discrimination tests for assessing the ability of consumers to discriminate between milks with subtle differences were designed by applying familiarization procedures to induce an affective/synthetic and analytical/synthetic perceptual strategy. The tests were then administered to 100 milk consumers and compared. In both same-different discriminations, consumers adopted a cognitive decision rule that used a β-strategy rather than a τ-strategy. Discrimination tests employing an affective/synthetic perceptual approach (which is the normal consumer perceptual process) resulted in higher discriminability than tests that employed an analytical/synthetic approach. Inter-individual differences in the consumer criteria (boundaries) used for same-different ratings were studied by examining the response distributions over the given response categories for the same pairs. According to the similarity of such response distributions, two different consumer segments were classified and their group discriminabilities differed significantly, with only the more sensitive group showing interactions between the affective/hedonic state and perceptual discriminability. [Copyright &y& Elsevier]

The literature includes many studies that use the shape of the receiver operating characteristic (ROC) curve derived from the same–different test to ascertain the decision strategy used by the judge: a symmetrical ROC curve indicates a β -decision strategy, and an asymmetrical ROC curve indicates a τ -decision strategy. These studies have not considered the effect that breaches of the assumptions that underlie the standard same–different model would have on inferences drawn from the shape of the ROC curve. Three such assumptions are investigated: the equal-variance assumption; the assumption of no stimulus order effects; and the assumption that the discriminability of the two stimuli is the same when presented first or second in the test sequence. Simulations indicate that the shape of the ROC curve is very tolerant of the breach of these assumptions. Consequently, inferences about the decision strategy used by a judge are fairly robust, and confidence in published results is upheld. PRACTICAL APPLICATIONS The same–different test is frequently used to determine the decision strategy adopted by judges. There are several assumptions made about the same–different test that may, if they were breached, undermine this test's ability to indicate the judge's decision strategy. The simulations conducted in this research indicate that the shape of the same–different ROC curve is very robust to breaches of these assumptions. Consequently, food scientists can maintain their confidence in the inferences made in the research already published on this topic, and in their own future research and development of sensory testing methods. [ABSTRACT FROM AUTHOR]

• Triadic designs of preference tests with a no-preference option were tested. • They were duo-trio difference-preference (DT-Preference) and triadic preference. • Odd sample bias was confirmed for them using stimuli with negligible preference. • Replicated preference data per subject could be obtained from DT-Preference. • 2-AC analysis on such replicated preference provides results with less preference bias. Two preference test methods utilizing triadic designs (i.e., presenting two identical products and a different product in a test) have been proposed to improve the validity of the paired preference test using a no-preference response option, by considering responses generated from preference bias (i.e., consumers' responses are tilted toward a preference response rather than a no-preference response, resulting in the overestimation of preference responses). One of the test methods was the replicated duo-trio difference-preference (DT-Preference) test method, which had a balanced-reference design, while the other was the triadic preference test method. These two methods were designed to provide more conservative preference results in different ways. For the DT-Preference test method, it was assumed that the preference responses that were simply generated from the preference bias would also be prone to an odd sample bias (i.e., consumers tilted the preference against the stimulus that was most different from the other two) in the triadic design. For the triadic preference test method, the responses were screened out if the subjects reported a preference between the identical stimuli, assuming no bias in the triadic design. In the present study, the odd sample bias assumed in the triadic design was tested by the triadic preference test method and the DT-Preference test method by using two pairs of confusable orange juice stimuli assumed to have negligible preference by 256 consumers. For the DT-Preference test method, two variants of the duo-trio test designs were used. The odd sample bias was confirmed for all test methods using triadic designs, invalidating the application of the triadic preference test method without replication. [ABSTRACT FROM AUTHOR]

[Display omitted] • The efficacy of the reminder-preference test was examined. • It exhibited performance comparable to both the reminder and preference tests. • Preference questions tightened the decision criterion for the difference test. • Sensory difference questions led to higher instances of no-preference responses. • The test allowed concurrent evaluation of blind and branded sensory preferences. Preserving the sensory characteristics of reformulated products is crucial for a successful market launch. This underscores the need for precise measurement of consumer perceptions regarding sensory differences and preferences. One approach to assess these aspects is through the utilization of the reminder-preference test, an affective difference-preference test employing the A-Not A with the reminder (A-Not AR) test design. This test measures sensory differences and preferences by employing a consolidated d ′ index rooted in signal detection theory and Thurstonian modeling. The aim of this study was to assess the efficacy of the reminder-preference test in measuring the degree of sensory differences and interpreting their relevance concerning consumer preference. To achieve this, the test was compared with both the A-Not AR difference test and the 2-alternative choice (2-AC) preference test. A lemon-lime-flavored carbonated drink and two types of reformulated samples were tested. Young female adult subjects were randomly divided into three groups. Each took one of the following three tests: the reminder-preference test, the reminder test of A-Not AR, or the 2-AC preference test. The reference framing in the reminder-preference and reminder tests was preceded by subjects watching the product's advertisement to assist them in framing evaluative criteria. This would also facilitate memorizing the perception of the reference product. Test sensitivity in reminder-preference matched reminder and 2-AC tests for sensory differences and preferences. Affective framing enhanced sensitivity to sensory differences resulting in a higher d′ value of the sensory difference than the preference. From the results, it was possible to interpret that the measured sensory differences did not affect consumer preference. The test also illuminated brand marketing effects on preferences through branded reference comparison. Thus, the reminder-preference test shows potential as an efficient sensory method to measure sensory differences and the preference of consumers, while concurrently measuring the effects of marketing on the consumers. Therefore, it can assist in making efficient business decisions regarding product reformulations. [ABSTRACT FROM AUTHOR]

[Display omitted] • The efficacy of the reminder-preference test was examined. • It exhibited performance comparable to both the reminder and preference tests. • Preference questions tightened the decision criterion for the difference test. • Sensory difference questions led to higher instances of no-preference responses. • The test allowed concurrent evaluation of blind and branded sensory preferences. Preserving the sensory characteristics of reformulated products is crucial for a successful market launch. This underscores the need for precise measurement of consumer perceptions regarding sensory differences and preferences. One approach to assess these aspects is through the utilization of the reminder-preference test, an affective difference-preference test employing the A-Not A with the reminder (A-Not AR) test design. This test measures sensory differences and preferences by employing a consolidated d ′ index rooted in signal detection theory and Thurstonian modeling. The aim of this study was to assess the efficacy of the reminder-preference test in measuring the degree of sensory differences and interpreting their relevance concerning consumer preference. To achieve this, the test was compared with both the A-Not AR difference test and the 2-alternative choice (2-AC) preference test. A lemon-lime-flavored carbonated drink and two types of reformulated samples were tested. Young female adult subjects were randomly divided into three groups. Each took one of the following three tests: the reminder-preference test, the reminder test of A-Not AR, or the 2-AC preference test. The reference framing in the reminder-preference and reminder tests was preceded by subjects watching the product's advertisement to assist them in framing evaluative criteria. This would also facilitate memorizing the perception of the reference product. Test sensitivity in reminder-preference matched reminder and 2-AC tests for sensory differences and preferences. Affective framing enhanced sensitivity to sensory differences resulting in a higher d′ value of the sensory difference than the preference. From the results, it was possible to interpret that the measured sensory differences did not affect consumer preference. The test also illuminated brand marketing effects on preferences through branded reference comparison. Thus, the reminder-preference test shows potential as an efficient sensory method to measure sensory differences and the preference of consumers, while concurrently measuring the effects of marketing on the consumers. Therefore, it can assist in making efficient business decisions regarding product reformulations. [ABSTRACT FROM AUTHOR]

• Dual reminder A-Not A(DR A-Not A) designed to detect off-sensory characteristics. • This method was tested on practicality of quality management of drinking water. • For using DR A-Not A with two odd stimuli, the optimal β-strategy was adopted. • Performance of unspecified DR A-Not A was comparable to that of specified 3-AFC. • Dual reminder scheme found to be an efficient practice to utilize SDT A-Not A model. Although the relative performance of sensory discrimination methods is well theorized in Thurstonian modeling and signal detection theory (SDT), empirical research is needed to investigate how such theorized models could be validated in complex sensory testing situations of food and beverages. This paper presents a practical procedure to utilize the existing SDT-based A-Not A sensory discrimination model based on a beta-strategy for detecting the off-sensory quality of samples of drinking water and validates the model for effective and efficient sensory quality management of food and beverages. Dual reminder A-Not A (DR A-Not A) using two tastings of the reference stimulus before evaluating every test stimulus is proposed as the optimal test procedure because it uses more sensitive test sequences and facilitates subjects' familiarization with the standard quality of the reference. To test the performance of DR A-Not A, 3-AFC, which also uses three stimuli and is the recommended method for detecting odor or taste stimuli by ASTM, was used as a control method. In Experiment 1, 98 subjects each performed both DR A-Not A and 3-AFC. Based on these results, only sensitive subjects were selected for the next experiment, in which they were divided into two equally well performing groups. In Experiment 2, each group performed either DR A-Not A or 3-AFC over three repeated sessions. The results confirmed that the A-Not A beta-strategy was adopted for DR A-Not A and that its test performance was improved over replications. These results suggest that although DR A-Not A is an unspecified difference test method and does not use a forced-choice task, embedding the familiarization procedure for the reference renders it an effective sensory difference method for the sensory quality management of drinking water. [ABSTRACT FROM AUTHOR]

Highlight • The degree of satisfaction-difference (DOSD) method was further studied. • The focus was on optimizing a specific consumer relevant attribute. • The new DOSD method provided reliable product discrimination as hedonic scaling. • The DOSD allowed to segment consumers based on the satisfaction to the reference. • Results showed the potential of the DOSD as an alternative to hedonic scaling. Abstract A specific attribute can play an important role in determining consumers' perceived quality and acceptance of a product. Kim, van Hout, Dessirier, and Lee (2018) proposed a new affective method, the degree of satisfaction-difference (DOSD) method, to study consumer acceptance in terms of overall satisfaction with products. In the present study, this DOSD method was further developed to assess satisfaction for a specified attribute of products rather than overall satisfaction, and this modification is referred to as the attribute-specified DOSD method. To test its applicability, 11 bouillon products (including a reference product) varying in viscosity were used as stimuli. Satisfaction with the perceived mouthfeel thickness, which is a viscosity-related sensory attribute, was evaluated with the attribute-specified DOSD method and with a 10-point category scale for overall liking as the control method. Two groups of consumers performed either the attribute-specified DOSD method or hedonic scaling over two repeated sessions. Results showed that the satisfaction patterns of the attribute-specified DOSD method were similar to those of the hedonic scaling across products, confirming that the mouthfeel thickness was a determinant of consumer acceptance for bouillon products. Examining the test reliability in terms of consistency of consumers' responses for the same stimulus in different sessions, both groups showed consistent results. The subjects who performed the attribute-specified DOSD method were also segmented based on the degree of satisfaction with the reference product. Here, each consumer sensory segment showed different patterns on satisfaction with other test products. These findings demonstrate the potential of the attribute-specified DOSD method for measuring the consumer responses to the level/quality of an important attribute/dimension and highlight its usefulness for consumer sensory segmentation. [ABSTRACT FROM AUTHOR]

Predictions of consumer acceptance are often based on hedonic scores, but these are determined not only by the consumer level of product liking, but also by consumer scale usage, which in turn is affected by thinking style and experimental contexts. To improve the validity and reliability of consumer acceptance measurement, a new indirect scaling method, the ‘Degree of Satisfaction-Difference (DOSD)’, was developed using a reminder design and signal detection theory (SDT). In DOSD, a product-specified ‘cognitive warm-up’ was used to evoke the consumer personal context and the internal evaluative criteria prior to product evaluation. In DOSD, each test product was presented together with a fixed-reference (identified as such) and consumers were asked to evaluate their satisfaction with the reference first with a sureness rating, and then to evaluate the test product for both absolute satisfaction and comparative satisfaction to the reference. The reliability of DOSD was tested against traditional hedonic scaling using an independent samples design of two consumer groups with equivalent cognitive reflection test profiles, each including High Reflection Thinkers (HRTs) and Low Reflection Thinkers (LRTs) in equal proportion. Each group tested two sets of skin lotions differing in product range, either using DOSD or hedonic scaling. When examining the affective discriminations of the two common products in terms of d ′ values between product sets, the LRT subjects generated inconsistent responses with hedonic scaling, but reproducible responses with DOSD. The HRT subjects performed consistently using both scaling methods. These results validate DOSD’s superior reliability in affective tests and demonstrate its potential as an alternative consumer acceptance measurement to hedonic scaling. [ABSTRACT FROM AUTHOR]

In the fast moving consumer goods industry, unspecified (overall) sensory difference tests are commonly used with sensory panels to compare multiple types of stimuli against a gold standard. In order to measure sensory differences accurately and reliably, it is important to investigate the efficiency of unspecified sensory difference test methods not only in terms of statistical test power, but also in practice, i.e., operational test power. One unspecified difference test method, the duo-trio method using constant-reference, is procedurally equivalent to the 2-AFC with reminder (2-AFCR), for which the 2-AFC decision strategies can be used by performing a comparative categorization task. However, the feasibility and efficiency of the comparative categorization task using a constant-reference duo-trio method has not been tested for the discrimination of multiple stimuli from a reference. The objectives of the present study were 1) to evaluate the adoption of the 2-AFC decision strategy in such comparative categorization methods for discriminating multiple products from a reference, and 2) to compare the efficiency and power of these comparative categorization methods with the unspecified tetrad and balanced-reference duo-trio methods. Using two sensory panels to discriminate two different iced tea stimuli from a reference, our results confirmed that a 2-AFC strategy can be adopted in comparative categorization methods without specifying sensory attributes. With an equal number of tastings, the comparative categorization methods using a 2-AFC strategy showed comparable operational test power with the unspecified tetrad method. Among the two versions (using a constant-reference duo-trio with the reference at the first position (DTF) and duo-trio with a reference presented first and in the middle of two alternative stimuli (DTFM)) of the comparative categorization methods examined in the present study, DTF was more reliable across repeated sessions than other unspecified methods investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Subjects with a loose vs a strict criteria responding to A-Not A ratings were sub-grouped for the pooling approach. • It studied the effects of modified test protocols on sensory learning and quality of results. • Reference categorization FP and a test design with a higher RPP was most effective. • With this, both sub-groups improved performance by stabilizing decision criteria. • The new recognition index, d′ Rec could monitor the changes in subjects' performance. Signal detection theory (SDT) sensory discrimination analysis using A-Not A with a two-step rating is an efficient approach to in-house sensory quality management in the food industry. For such sensory analysis using an internal panel, the panels' ability to use stable decision criteria and provide a consistent response distribution responding to "A" vs "Not A" is critical for guaranteeing the data quality. This study examined the effects of the familiarization procedure (FP) and reference presentation probability (RPP) in the SDT A-Not A rating protocol on the panels' sensory learning of samples and stability of decision criteria using SDT parameters, recognition d' (d' Rec),criteria location (c), and discrimination d' indices. Three different protocols were compared using ice-tea samples with small differences: Control, 0.25 RPP with repeated reference tasting (FP R); Modified-1, 0.25 RPP with reference categorization (FP C); Modified-2, 0.5 RPP with reference categorization (FP C). An independent sample design with three groups having equal sensitivity was used to identify the differences among the protocols. For each protocol, two sub-groups with similar decision criteria (response bias) were formed according to the results obtained from the pre-test and used for the main-test analysis. SDT analysis results indicated that the Modified-2 protocol with a higher RPP (0.5) induced the most efficient sensory learning of the reference. The protocol improved the subjects' recognition of the reference and test samples, better differentiating from the reference and stabilizing the decision criterion, resulting in higher discrimination performance (larger d'). The results showed that d' Rec analysis, together with d' analysis using a sensory panel, is a useful tool for monitoring the panel performance and checking for the sensory data quality of the sensory difference tests. In the present paper, a detailed illustration of the A-Not A sensory test procedure and examples of how to apply the SDT indices for different business decision-making is also introduced using the design and results of the present experiment. [ABSTRACT FROM AUTHOR]

To measure consumers’ product usage experience throughout the various product usage stages, a novel two-step rating-based ‘double-faced applicability’ test has recently been proposed by Kim et al. (2017). In this method, a ‘two-step’ rating (forced-choice Yes/No questions followed by 3-point sureness ratings) and ‘double-faced’ descriptors (a pair of semantic-differential descriptors) are used for each attribute to improve the product discriminability by reducing consumers’ response bias and variations. In this paper, we introduce a novel measure that can be computed from the data from the ‘double-faced applicability’ test to provide a new way to generate affective product usage experience profiles. The novel measure was a nonparametric estimate of affect magnitude, named as d-prime affect magnitude ( d ′ A ), computed by considering the response ratio of positivity to negativity as the ratio of signal to noise in the context of Signal Detection Theory (SDT). The advantage of using this new measure d ′ A was that it meaningfully reflected the consumers’ affective product usage experience for each product independently (and how this affect valence changed through a usage process), yet it can still be used to compare between products. The practical application of using d ′ A was demonstrated in comparison to the more conventional SDT measure d ′. [ABSTRACT FROM AUTHOR]

Due to its simplicity and efficiency for evaluating product attributes, check-all-that-apply (CATA) questions have been widely used. Yet, CATA questions have been reported to lack discriminability of subtle product differences and suffer from the problems of response bias from satisficing and acquiescence behaviors. In the present paper, a novel two-step rating-based ‘double-faced applicability’ test was developed as an extended response format of CATA, to improve its sensitivity for product discrimination and for stabilizing subjects’ evaluative criteria. In the ‘double-faced applicability’ test, each attribute was ‘double-faced’, meaning that two descriptors (a pair of semantic-differential descriptors) are separately presented in the questionnaires representing both sides of each attribute. For performing the two-step rating on each attribute in the questionnaire, subjects are instructed to first respond ‘Yes (does apply)’ or ‘No (does not apply)’ and then to answer a 3-point sureness rating (how sure they were about their Yes or No response). The performance of the two-step ratings in this new method was compared to a simple one-step applicability rating test method as well as the forced-choice Yes/No questions without the sureness rating in terms of sensitivity in sample discrimination. The results showed that the ‘double-faced applicability’ test provided better product discrimination and showed the potential to reduce acquiescence response bias when using existing variants of CATA response formats. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel SDT-based detection threshold method of oral/taste sensitivity to NEFA was proposed. • It used repeated descending-block DR A-Not A tests with a warm-up procedure. • Using this novel method, hypo-sensitive subjects also showed learning over repeated testing. • This resulted in lower variability in group median thresholds. • On the other hand, using the ascending triangle method, hypo-sensitive subjects did not show learning effects. Accumulating psychophysical evidence suggests substantial individual variability in oral/taste sensitivity to non-esterified, long-chain fatty acids (NEFA), which is commonly referred to as fat taste or oleogustus. Recent studies have sought to determine its associations with human factors such as body mass index (BMI) and food preferences, as it has been claimed that excessive fat consumption is related to several health conditions, including obesity. Yet, the findings are controversial. On the other hand, it has been noted that considerable variability also occurs based on the methodology used to measure the fatty acid taste. Specifically, learning effects have been observed over repeated measurements of the detection threshold of NEFA, yet there has been no methodology available to take into account these learning effects. Accordingly, in the present study, a novel methodology using a descending-block dual reminder A-Not A (DR A-Not A) method with a warm-up has been proposed to measure the NEFA detection threshold based on the signal detection theory and considering NEFA taste learning effects over repeated sessions. Homogeneous subjects (young adult Korean females within the normal BMI range, non-vegetarians) were randomized to either the novel descending-block DR A-Not A method or ascending triangle method that is commonly used for fat perception studies. Pure oleic acid emulsions were used as fat taste stimuli to be discriminated from pure mineral water. Each subject completed 14 repeated visits. For the ascending triangle method, 14 thresholds were determined using a stopping rule, while for the novel method, 7 thresholds were determined each per two consecutive days, using a criterion of a lower limit of 50% confidence interval of d' = 0.5, considering the practical aspects of taste studies in food sensory science. Based on the group median results of the last two visits, the variability of the detection thresholds was reduced using the novel descending-block DR A-Not A method due to better learning effects over repeated sessions. This shows the potential of the descending-block DR A-Not A threshold method for further studies on oral/taste sensitivity to fat. [ABSTRACT FROM AUTHOR]

In the food industry, overall discrimination tests are used with untrained/naïve consumer subjects to compare multiple test stimuli against a fixed reference, such as a company’s gold standard or a stimulus familiar to the consumer. Such tests are used for various objectives, including reformulation and cost reduction. Yet, studies on relative discrimination power and efficiency have been limited to experimental designs with a fixed pair of stimuli and method comparisons based on the same numbers of tests. In the present study, two reminder methods, A-Not A with Reminder (A-Not AR) and 2-AFC with Reminder (2-AFCR), were investigated as potentially better methods for experimental designs including comparisons of multiple pairs of stimuli for consumer discrimination. 2-AFCR is procedurally equivalent to a constant-reference duo-trio test with the reference presented first (DTF) and thus this test is referred to as the constant-ref. DTF/2-AFCR test in this paper. The practical efficiency of these two reminder methods, attributed to their effective stimulus configurations in replicated tests (i.e. using a fixed reference and lower number of different stimuli required in a test), was tested in comparison with the two most commonly used balanced reference classification methods, the triangle test and the unspecified tetrad test, by equalizing the number of stimuli required for the different methods. Namely the relative operational discrimination power was studied based on the same number of stimuli rather than the same number of tests. 180 naïve consumers performed a set of 12 replicated triangle tests and, based on the results, were divided into one of three equally-performing groups. A related-samples design was implemented for comparison between the triangle and the other three methods. An independent-samples design was implemented across the three groups to compare the A-Not AR, constant-ref. DTF/2-AFCR, and unspecified tetrad methods. Statistical ratio comparisons of d ′ estimates obtained from different methods revealed that discrimination performance in the reminder methods was better than in both the tetrad and triangle methods. No discrimination difference was found between the triangle and tetrad tests having all possible test sequences, although the triangle test considering only the optimal test sequences, which were the same as those in the constant-ref. DTF/2-AFCR, resulted in superior discrimination than the tetrad test. Collectively, these results suggest that when assessing the discriminability of multiple stimuli from a fixed reference, the reminder scheme is the superior research design. [ABSTRACT FROM AUTHOR]

As sodium reduction has become very important in the food industry, various types of unspecified duo–trio tests have been studied to improve its efficiency for studying samples with high sodium content, and a constant-saltier-reference duo–trio test with dual reference, one reference in the first position and the second reference in the middle between the two test stimuli (DTFM), has been recommended. For the duo–trio test, a ‘comparison of distance’ (COD) strategy has been generally assumed. Yet, theoretically for DTFM, the 2-AFC reminder (2-AFCR) τ -strategy is also possible, which would make DTFM more efficient than the unspecified tetrad test. In this study, the hypothesis was that when subjects are pre-exposed to two types of samples, the 2-AFCR τ -strategy can be adopted in a constant-reference DTFM using a fixed design experiment. In order to test this hypothesis, unspecified tetrad tests involving categorization tasks were used as a means of pre-exposure to the two types of samples for DTFM, and a performance comparison was conducted. Two groups of 39 untrained/naive subjects performed both the unspecified tetrad and DTFM tests in varying orders for the purpose of discriminating two different soup samples of varying sodium content. A comparison of the d ′ estimate across different methods supported the hypothesis that the more efficient 2-AFCR τ -strategy was appropriate when the tetrad test preceded DTFM, while when DTFM was performed first without pre-categorization of samples, the conventional duo–trio COD strategy was appropriate for the constant-reference DTFM. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new consumer sensory measurement, "reminder-preference test" was introduced. • The reminder task uses A-Not A design with a branded reference tasted first. • An ad for the reference was watched as an affective familiarization before tests. • It yields both sensory and preference measures in d ′ using signal detection theory. • It resulted in superior performance than the "same-different difference-preference test". Attempts to reduce the sugar content of carbonated drinks are ongoing. Reducing the sugar content while maintaining the sensory quality requires the development of an effective sensory test method that can measure a consumers' perceived sensory difference and preference of reformulated products against the reference product. The A-Not A with reminder (A-Not AR) method (sometimes called the reminder method) allows blind sensory tests of multiple test samples vs. a reference, while for the reference, marketing information, such as brand name and advertisements emphasizing the consumer benefit, can be provided to improve the marketing effects and consumer expectation. Thus, a preference test method can also simulate branded tests using A-Not AR design with a branded reference, making them suitable for consumer sensory tests. In the present study, an affective difference-preference test method using an A-Not AR design with the reference familiarization procedure of providing marketing information was developed, called the "reminder–preference test". The "reminder–preference test" sensitivity was compared with the previously suggested version of the "same–different difference–preference test", using signal detection d′ analyses. A lemon-lime flavored carbonated drink was used as the reference and compared with two types of reformulations. The consumers were divided randomly into two groups that performed one of the two difference-preference test methods. With the "reminder–preference test", the consumers watched a commercial advertisement for the reference by providing its brand name before the tests to evoke the marketing effects. The proposed sensory test of the "reminder–preference test" was more sensitive than the "same–different difference–preference test", in terms of both sensory and preference discriminations. Hence, brand effects can be incorporated into the consumer sensory evaluation to achieve the reformulation objective and the potential of the "reminder–preference test" and its signal detection d′ analyses to improve the effectiveness and efficiency of consumer sensory measurements. [ABSTRACT FROM AUTHOR]

Highlights: [•] For duo-trio and same-different tests, significant sequence effects were confirmed. [•] Sequence effects resulted in operational effects for different test designs. [•] For DTF and DTFM, the saltier-reference scheme showed the higher test performance. [•] Such DTF and DTFM found superior to same-different tests with balanced-design. [Copyright &y& Elsevier]

Highlights: [•] Test performances were compared using the d′ in relation to the operational power. [•] The constant-reference duo–trio was more operationally powerful than the triangle. [•] The d′ of duo–trio was improved by using affective framing of constant-reference. [•] For the balanced-reference triangle test, significant sequence effects were found. [•] For the constant-reference duo–trio test, sequence effects were not significant. [ABSTRACT FROM AUTHOR]

• Humans can discriminate between fat levels in food, using solely retronasal odours. • Fat discrimination ability is comparable between the two olfaction routes. • The ability to discriminate between food fat levels seems to be unaffected by habitual intake. • Chemical signals underlying olfactory fat discrimination remain unknown. Dietary fat overconsumption contributes to the development of obesity and related comorbidities; however, its sensory perception is poorly understood. Although humans can discriminate between vapor-phase fatty acids, both ortho- and retronasally, evidence of orthonasal fat discrimination in real foods is limited, and non-existent for retronasal olfaction. In two experiments, we investigated the human ability of olfactory food fat content discrimination in dairy milk and assessed whether this ability is affected by habitual dairy intake. Participants undertook a series of DR A-not A discrimination tests (analysed with R-index analyses) coupled with perceptual ratings and a questionnaire on dairy consumption habits. In the first experiment (n = 66), ortho- and retronasal discrimination was evaluated using dairy milk samples manipulated to contain 0%, 1.5% and 3.5% fat. Subjects could discriminate between all three fat levels orthonasally (p <.001), whereas retronasally they were able to do so between 0 and 1.5% (p <.001) and 0–3.5% (p <.001). The second experiment (n = 44) focused only on retronasal discrimination, using (manipulated) dairy milk samples of 3.5%, 7%, 10.5% and 14% fat. Here, discrimination was possible between 3.5 and 14% (p <.001) and 7–14% (p <.05) samples. No effects of total dairy fat intake, total dairy product intake or dairy exposure frequency were observed on discrimination ability in both experiments. This is the first study demonstrating that humans are capable of discriminating food fat content solely based on retronasal olfaction. Results also suggest that this ability is unaffected by habitual intake. [ABSTRACT FROM AUTHOR]

Abstract: The A–Not A difference test can be used to measure the overall sensory difference of two or more products from a reference product. It is an economically efficient method for difference testing because it is more statistically powerful and less prone to working memory problems than the triangle or duo–trio tests. With the A–Not A test, subjects are required to be familiar with the reference product to stabilize their cognitive decision criteria. An effective familiarization procedure is needed. In the present study, the effects of four different familiarization procedures were investigated: (1) 2-AFCR, (2) no-additional familiarization, (3) repeated tastings of the reference, and (4) repeated tastings of the reference with a brand image provided. Two products were discriminated from a reference using 12 subjects over repeated sessions. Comparisons of the test performances, analyzed with d′ estimates, showed that there was a tendency toward better discrimination when repeated tastings of the reference were accompanied by a brand image. [Copyright &y& Elsevier]