Effects of Expectations on Negative Affect, Perceived Cognitive Effort, and Pain
Condition: Placebo; Expectations
Study type: Interventional

Summary: 
      The investigators administer a functional neuroimaging task to investigate the effect of cue
      expectancy on participants' self-reported ratings across a variety of affective and cognitive
      domains. The experiment incorporates three tasks in which participants experience and rate 1)
      somatic pain, 2) vicarious pain, and 3) cognitive effort. In the somatic pain task,
      participants receive a brief thermal stimulus administered to a site on their arm; in the
      vicarious pain task, participants watch a short video clip of a patient with back/shoulder
      pain; in the cognitive effort task, participants perform a cognitively demanding "mental
      rotation" task that requires them to indicate whether two 3D objects are the same or
      different when rotated along the y-axis. Each trial follows a sequence that begins with a
      fixation, followed by a social influence cue, then an expectation rating, followed by a
      condition-specific stimulus, and then, an actual rating of the outcome experience.

      There are four events of interest: 1) cue perception, 2) expectation rating, 3) stimulus
      experience, and 4) outcome rating.

      First, participants are presented with a cue that depicts how other participants responded to
      the upcoming stimulus ("cue perception"). Although the participant is told these are real
      ratings, they are in fact, fabricated data points that vary in intensity (low, high). Then,
      based on the provided cues, participants are prompted to report their expectation of the
      upcoming stimulus intensity ("expectation rating") After providing an expectation rating,
      participants are presented with a condition-specific stimulus (somatic pain, vicarious pain,
      or cognitive effort) that also varies in three levels of low, medium, high stimulus intensity
      ("stimulus experience"). Once the stimulus presentation has concluded, participants are
      prompted to provide an actual rating of their experience ("outcome rating"). For the somatic
      pain condition, participants rate their expectations and actual experience of how painful the
      stimulus was; for the vicarious pain condition, they rate their expectations and actual
      perception of how much pain the patient was in; and for the cognitive condition, the
      participant provides expectation and actual ratings of task difficulty.
    


Intervention name(s): Pain Expectancy Cues; Vicarious Pain Expectancy Cues; Cognitive Effort Expectancy Cues
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Participants are presented with a social cue that represents how previous participants responded to the upcoming somatic pain stimulus. In actuality, the cue is a social placebo, constructed by the experimenters and varying in intensity.; Participants are presented with a social cue that represents how previous participants responded to the upcoming vicarious pain stimulus. In actuality, the cue is a social placebo, constructed by the experimenters and varying in intensity.; Participants are presented with a social cue that represents how previous participants responded to the upcoming cognitive effort stimulus. In actuality, the cue is a social placebo, constructed by the experimenters and varying in intensity.
Intervention model: Single Group Assignment
Intervention model description: Within-participant design with behavioral manipulations
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Social Placebo; Somatic Pain; Vicarious Pain; Cognitive Effort