Mouth state: A nuisance variable in preference tests?

An artificial mouth-drying procedure was used to assess the impact of mouth-dryness on the pleasantness of drinks. Experiment 1 showed that mouth dryness increases the pleasantness of 3 degrees C water more than warmer water (13 degrees C, 23 degrees C and 33 degrees C). Experiment 2 showed that mouth dryness increases the pleasantness of a high acid (3.5 g 1000 ml(-1)) lime drink, but not a medium (1.75 g 1000 ml(-1)) or a low acid (0 g 1000 ml(-1)) lime drink. In both experiments, elevated saliva flow rates were recorded for those drinks that were regarded as more pleasant in the dry-mouth condition than in the control condition. Shifts in preference may be linked to saliva flow because mouth-wetting drinks may offer greater relief from dry-mouth sensations. Our interpretation implies that an adjustment of palatability assessment procedures, taking into account mouth-state effects, may now be warranted. (C) 1997 Elsevier Science Ltd. All rights reserved.