Corroborating the 2-AFC and 2-AC Thurstonian models using both a model system and sparkling water

Sensory difference tests: Overdispersion and warm-up

“…Rousseau and OÕMahony (2001) working with orange drinks found no overdispersion with triangle and same-different tests. Braun, Rogeaux, Schneid, OÕMahony, and Rousseau (2004) using 2-AFC tests, reported overdispersion with a gamma value of 0.036, which was significantly greater than zero. Yet, it could be argued that the value was unimportantly small and only significant because of the large sample size.…”

The paired preference test and the ‘No Preference’ option: was Odesky correct?

“…Using difference tests, Braun et al (2004) compared d 0 values obtained by the 2-AFC (ÔNo DifferenceÕ option not allowed) with those from the 2-AC method (ÔNo DifferenceÕ option allowed). Using NaCl solutions and sparkling water stimuli, they found no significant differences between d 0 values obtained from the two methods, as would be expected from Thurstonian theory.…”

“…For the preference tests without a ÔNo PreferenceÕ option, d 0 values were obtained in the same way as for a 2-AFC, using tables of d 0 (Ennis, 1993). For preference tests with the ÔNo PreferenceÕ option, d 0 values were obtained using a 2-AC computation (Braun, Rogeaux, Schneid, OÕMahony, & Rousseau (2004)). Tests of significance were performed using the method of Bi, Ennis, and OÕMahony (1997).…”

Be your own placebo: A double paired preference test approach for establishing expected frequencies

“…These were computed using a 2-AC computation (Braun, Rogeaux, Schneid, O'Mahony, & Rousseau, 2004). Computations were performed using the IFPrograms software (JAR program, Institute for Perception, Richmond, VA).…”