Monitoring scaling drift for hedonic category scales

Judges on anti-nausea medication, used hedonic scales to assess a set of foods and beverages on two occasions, initially on beginning a treatment with anti-nausea medication and then four weeks later. To detect the possibility that changes in hedonic scores for the foods and beverages may be caused not by changes in liking but by 'scaling drift': changes in the use of the scale, control stimuli were also assessed. These control stimuli were sets of stimuli to be assessed for intensity and a set to be assessed for liking. These latter stimuli were a class of stimuli that were unlikely to be liked to a different extent on the two testing occasions. The lack of change in the control stimuli and the change in the hedonic scores for the foods and beverages suggested that the latter was due to changes in liking for the foods and beverages rather than 'scaling drift'.