Doctor of Philosophy (PhD)
School of Nutrition and Food Sciences
Literature concerning children’s performance in sensory discrimination methods is not as extensively published as performance with adults. Therefore, in this dissertation children’s performance in discrimination methods was investigated. First, performance in the triangle and 3-AFC methods was explored with children 6 to 12 years old. The paradox of discriminatory non-discriminators states that the proportion of correct responses in the 3-AFC method will be higher than that of the triangle. However, Thurstonian theory predicts that despite the difference in proportions of correct responses the degree of difference between the stimuli will be similar. The paradox and the Thurstonian predictions were challenged for sweetness discrimination with three different sets of stimuli: easily discriminable (100% vs. 60% apple juice), confusable (100% vs. 75% apple juice) and hardly discriminable (carbonated beverages with different sweeteners). For easily and hardly discriminable stimuli the paradox and Thurstonian predictions were not fully confirmed. With confusable stimuli the paradox (3-AFC Pc = 0.62; triangle Pc = 0.43) and Thurstonian predictions (3-AFC d' = 0.97; triangle d' = 1.09, p = 0.48) were confirmed. It is not known if the same results would be observed when the number of samples increases. Secondly, Thurstonian predictions regarding the variants of the method of tetrads were challenged using confusable stimuli. Results show that the number of correct responses and degree of difference among the stimuli for the unspecified and specified method of tetrads were similar. Finally, children’s performance in different discrimination methods was compared. Performance in the unspecified methods (tetrads and triangle) was as predicted by Thurstonian theory. For the specified methods the 2-AFC resulted in the highest proportion of correct responses, followed by the 3-AFC and the tetrads, respectively, as previously observed with adults as subjects. Results from this investigation give further support to the Thurstonian predictions discussed above, which had been tested only with adult subjects. In conclusion, under the circumstances of this study, children between 6 to 12 years of age were capable of performing sensory discrimination methods for sweetness perception and they utilized the same decision rules as adults.
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Garcia, Karen Melissa, "Sensory Discrimination Testing with Children" (2011). LSU Doctoral Dissertations. 3871.