title: Motivation and expectancy influences in placebo responding: the mediating role of attention.
abstract: Drawing upon research in perception and motivation, the current study proposes a motivation-attention model of placebo in which more motivated persons pay greater attention to placebo-related stimuli, directly influencing placebo response. We manipulated both motivation to respond to placebo and expectations of placebo response in a 2 × 2 design. Participants (N = 152) evaluated a series of placebo pheromones (slightly scented water) of potential romantic dates and made desirability ratings. Consistent with hypotheses, more highly motivated participants demonstrated greater placebo responses, as evidenced by higher desirability ratings of the "pheromone" and greater variability among ratings, when compared to less motivated participants. Moreover, the relation between motivation and placebo response was mediated by attention. Contrary to expectations, we found no effect for expectancy. These findings highlight the importance of motivation and the mediating factor of attention in placebo and support goal-oriented models of placebo.
authors.affiliation: Indiana University Purdue University Indianapolis, Indianapolis, IN, USA.
authors.forename: Carrie
authors.initials: C
authors.lastname: Aigner
authors.forename: Soren
authors.initials: S
authors.lastname: Svanum
mesh_terms: D000328:Adult; D001288:Attention; D003380:Courtship; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009042:Motivation; D009812:Odorants; D010675:Pheromones; D015990:Placebo Effect; D014481:United States
chemical_list: D010675:Pheromones
keywords: Expectancy; Motivation; Placebo