title: The power of positive and negative expectations to influence reported symptoms and mood during exposure to wind farm sound.
abstract: OBJECTIVE
  Wind farm developments have been hampered by claims that sound from wind turbines causes symptoms and negative health reports in nearby residents. As scientific reviews have failed to identify a plausible link between wind turbine sound and health effects, psychological expectations have been proposed as an explanation for health complaints. Building on recent work showing negative expectations can create symptoms from wind turbines, we investigated whether positive expectations can produce the opposite effect, in terms of a reduction in symptoms and improvements in reported health.
  
  
  METHODS
  60 participants were randomized to either positive or negative expectation groups and subsequently exposed to audible wind farm sound and infrasound. Prior to exposure, negative expectation participants watched a DVD incorporating TV footage about health effects said to be caused by infrasound produced by wind turbines. In contrast, positive expectation participants viewed a DVD that outlined the possible therapeutic effects of infrasound exposure.
  
  
  RESULTS
  During exposure to audible windfarm sound and infrasound, symptoms and mood were strongly influenced by the type of expectations. Negative expectation participants experienced a significant increase in symptoms and a significant deterioration in mood, while positive expectation participants reported a significant decrease in symptoms and a significant improvement in mood.
  
  
  CONCLUSIONS
  The study demonstrates that expectations can influence symptom and mood reports in both positive and negative directions. The results suggest that if expectations about infrasound are framed in more neutral or benign ways, then it is likely reports of symptoms or negative effects could be nullified.
authors.affiliation: Department of Psychological Medicine, University of Auckland.
authors.forename: Fiona
authors.initials: F
authors.lastname: Crichton
authors.affiliation: Acoustic Research Centre, University of Auckland.
authors.forename: George
authors.initials: G
authors.lastname: Dodd
authors.affiliation: Acoustic Research Centre, University of Auckland.
authors.forename: Gian
authors.initials: G
authors.lastname: Schmid
authors.affiliation: Department of Medicine, University of Auckland.
authors.forename: Greg
authors.initials: G
authors.lastname: Gamble
authors.affiliation: Department of Medicine, University of Auckland.
authors.forename: Tim
authors.initials: T
authors.lastname: Cundy
authors.affiliation: Department of Psychological Medicine, University of Auckland.
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Petrie
mesh_terms: D000293:Adolescent; D000339:Affect; D059026:Diagnostic Self Evaluation; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects*; D011210:Power Plants; D011209:Power, Psychological; D014742:Videodisc Recording; D014919:Wind; D055815:Young Adult