Phase 1: physiological and perceptual responses
nausea, nausea’
Physiological and perceptual responses to each condition were measured together. To minimize distractions, participants were seated at a desk facing a blank wall with noise cancelling headphones (Bose QuietComfort; Massachusetts, USA) playing brown noise. The procedure began with 15 min of rest during which participants became accustomed to their surroundings. Then, a remote-activated yellow light signalled to participants to slowly raise the solution and rinse it around the mouth (10 s) until the light was turned off. Participants were instructed to remain as still as possible for 1 min, while physiological measures were taken. Throughout the procedure, instantaneous heart rate was measured beat by beat using finger photoplethysmography (Finometer Pro; Finapres Medical Systems, Enschede, The Netherlands). Change in (∆) heart rate was then calculated as the difference between the maximum value after mouth rinsing the solution and the average 10 s value immediately preceding the mouth rinse.Once physiological parameters returned to baseline (1 min after solution ingestion), participants then completed perceptual questionnaires. Hedonic value and nausea were assessed using 10 cm visual analogue scales anchored by the labels 'highly pleasant’ and ‘highly unpleasant’, or ‘no nausea’ and ‘extreme nausea’, respectively. Unpleasantness and taste intensity were assessed using 20 cm adjusted general labelled magnitude scales (Green et al. The influence of taste on physiological markers of ANS activation (e.g., heart rate) has previously been documented (Gam et al. 