Two experiments were conducted to investigate the suitability of the Thurstonian models for the 2-AFC (2-alternative forced choice) and 2-AC protocols (2-AFC test with a "no difference" option). The Thurstonian approach predicts that if the same subjects and products are used, the degree of difference measured between the products (d0) should be the same. Experiment I tested thisprediction using solutions with different salt concentration. The average d0 values for the 2-AFC and 2-AC were found to be 1.66 and 1.54, respectively, and were not significantly different (t-test, p¼ 0:46). This indicated the suitability of the models for a taste stimulus. Experiment II used a trigeminal stimulus: sparkling water with different CO2levels as a food system. Three levels of carbonation were used and all three possible pairs of samples were compared. The d0 values measured for the 2-AFC and 2-AC for each pair of products were: pair 1––1.7 and 1.7; pair 2––0.8 and 0.7; pair 3––1.2 and 1.0. For each pair of products, no significant difference was observed between the d0 of each protocol (t-tests, p ¼ 0:65, 0.20, 0.30, respectively), giving further support to the Thurstonian models of these paradigms and indicating their robustness.
Braun, V., Rogeaux, M., Schneid, N., O’Mahony, M., Rousseau, B. (2004), Corroborating the 2-AFC and 2-AC Thurstonian models using both a model system and sparkling water. Food Quality and Preference, 15(6), 501-507.
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Corroborating the 2-AFC and 2-AC Thurstonian models using both a model system and sparkling water
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