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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]

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]

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]

• 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]

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]