Comparison of performance in the A-Not A, 2-AFC, and same-different tests for the flavor discrimination of margarines: The effect of cognitive decision strategies

Abstract

The performance of three different discrimination tests (A-Not A, 2-AFC, same-different) was investigated to explore the effects of varying aspects of the test protocols, such as the familiarization procedure and retasting of the reference (A), during testing on discriminability and the cognitive decision strategy used in the tests, when discriminating between the two different margarines. Seven judges, who were not familiar with margarine products, each gave 24 ratings for each of six protocols, resulting in 168 ratings in the pooled data, and from which R-indices and d′ estimates were calculated. When both test products were presented beforehand for familiarization, judges adopted the beta cognitive decision strategy. When only the reference (A) was presented to the judges beforehand for familiarization, and the reference (A) was retasted before the test product either by prescription or at will, the tau cognitive decision strategy was adopted. When the number of samples tasted within a test increased, discriminability was considerably decreased. Such differences between test protocols were explained in terms of the concept formation of the test products, carry-over and fatigue effects, and memory problems caused by longer time-intervals between tastings. © 2007 Elsevier Ltd. All rights reserved.