Investigating preference and discrimination via tetradic preference testing: A comparison with placebo preference testing and triadic preference testing
The No Preference option is employed increasingly, for example in preference testing related to advertising claims. However, published results indicate that relatively few consumers use No Preference, even for a putatively identical pair. To investigate preference and discrimination, and expressed preference consistency made possible from embedded replication, we evaluate three placebo-related tests:
(i) a placebo preference test, consisting of back-to-back preference tests with one different pair and one same pair;
(ii) a variant of the triadic preference test with two of three samples the same, modified such that the consumer first tasted samples and indicated whether there was a preference, and if so, the consumer answered a preference question, otherwise, a discrimination question (cf. Calderón et al., 2015); and
(iii) a novel tetradic preference test with two same pairs, following an analogous procedure.
Test types were allocated to 100 consumers following a complete block design. Within each test type, two product categories were tested, with samples similar in appearance but differing slightly in sensory properties: (a) fruit flavored drink (samples sweetened with 7% and 8% sucrose) and (b) potato chips (samples with full and reduced salt). Preliminary results follow. In all test types, No Preference is selected by <30% of consumers. Both discriminators and non-discriminators express no preference. Marginally, the sweeter beverage and saltier chips were preferred across all test types, but statistically significant only in the paired beverages test and triadic chips tests. Preference stability cannot be investigated in (i), but even consumers with preference consistency in (ii) and (iii) had preference inconsistency across test types. Results may suggest the importance of aggregate results for assessing products with relatively small sensory differences.
Lam, A., King, S. K., Findlay, C. J., & Castura, J.C. (2015). Investigating preference and discrimination via tetradic preference testing: A comparison with placebo preference testing and triadic preference testing. In: 11th Pangborn Sensory Science Symposium. 23-27 August. Gothenburg, Sweden.