INVESTIGATION OF TEST PERFORMANCE OVER REPEATED SESSIONS USING SIGNAL DETECTION THEORY: COMPARISON OF THREE NONATTRIBUTE-SPECIFIED DIFFERENCE TESTS 2-AFCR, A-NOT A AND 2-AFC

摘要

To investigate more flexible methods for measuring overall sensory differences, the performance of three nonattribute-specified difference test methods was compared using Signal Detection Theory. A-Not A, 2-AFC, and 2-AFCR tests were performed with experienced subjects over repeated sessions. Learning effects were investigated to determine how much training would be needed before subjects could perform these tests consistently. Results in d' showed that in early sessions, the 2-AFC and 2-AFCR performed better (higher d') than A-Not A and that after two sessions, the test performance stabilized on that level. Learning effects for the A-Not A test were poorer in the earlier sessions, with performance levels increasing, even after six sessions. In business situations where the tested products frequently vary, the use of 2-AFC and 2-AFCR would be recommended because they are more sensitive in the earlier sessions, requiring less training time than A-Not A.