Discrimination Theories and Advanced Topics

Abstract

Discrimination tests seem straightforward and simple in making decisions and recommendations about product differences. Usually, some simple choice test is conducted, numbers of correct choices are counted, and statistical significance is determined. When the number correct exceeds some cutoff, we have evidence against the null hypothesis and in favor of a relationship between our test variable and a perceivable sensory difference. So far so good. If this scenario were the limit of sensory science, sensory tests could be conducted by people with minimal technical experience, and there would be little need for highly trained sensory professionals. However, sensory professionals need to do more than simply “turn the crank” on routine tests and produce binary yes/no decisions about statistical significance. They are also required to understand the relative sensitivity of different test methods, the decision processes and foibles of sensory panelists, and the potential pitfalls of superficial decisions. Whenever possible, they should bring a deeper understanding of the test process and a greater ability to add interpretation to test results than is found in standardized analytical testing procedures. Each food or product is different. Business and research decisions may hinge on conclusions (reasoned judgments) and recommendations from interpretation of test results.

Difference testing methods constitute a major foundation for sensory evaluation and consumer testing. These methods attempt to answer fundamental questions about stimulus and product similarity before descriptive or hedonic evaluations are even relevant. In many applications involving product or process changes, difference testing is the most appropriate mechanism for answering questions concerning product substitutability—D. M. Ennis (1993)