Awareness Changes Placebo Effects for Feeling Relaxed, but not for Liking

Information and communication of beliefs can influence effectiveness and liking of food products. This study is the first to investigate how two positive states, activation and relaxation, can be associated with a product through communication, how this influences liking, and how manipulation awareness influences both liking and the association between positive states and the product. Three groups of participants received an unfamiliar herbal infusion. Group 1 was told that the herbal infusion would have activating properties, group 2 was told that it would be relaxing, and group 3 was given no information. During an 11-day home-consumption phase, 148 participants filled in a diary, detailing consumption and feelings of relaxation. On day 12, implicit and explicit measures of relaxation, liking, and manipulation awareness were taken after consumption. Participants in the relaxed condition felt significantly more relaxed than participants in the active and the control condition, but only if they were unaware of the experimental manipulation. Independently of awareness, participants liked the tea better in both the activating and the relaxing than in the control condition. Results show that a positive state can be connected with a product without employing active ingredients, and that liking increases as a consequence of this connection. Results also show a trend that manipulation awareness influences the effect on positive state, but not on liking.