Can the same-different test use a β-criterion as well as a τ-criterion?

Using low concentration NaCl and water stimuli, judges performed same-different tests and single stimulus discrimination tests. The data were subjected to a signal detection analysis. For single stimulus judgments, a β-criterion, dividing salt vs water is assumed for calculating d′. For the same-different method, a τ-criterion, a sensory yardstick designating the degree of difference required for a 'different' judgment, is assumed. ROC analysis indicated that for single stimulus judgments, a cognitive strategy involving a β-criterion was confirmed. Yet, ROC analysis for the same-different test indicated that prior or current use of a β-criterion carried over into the same-different test for some judges, giving a mixture of τ- and β-criteria.