Role of the Brain in Making Economic Decisions
Condition: Healthy
Study type: Observational

Summary: 
      This study will identify which areas of the brain mediate the interaction between people
      involved in economic decision-making.

      Healthy, right-handed native English speakers between 21 and 55 years of age may be eligible
      for this study. Candidates are screened with a telephone interview, a questionnaire to
      determine handedness, and a neurological examination if one has not been performed within the
      last year by an NIH physician.

      Participants bargain for money by playing two-person trust games, while undergoing functional
      magnetic resonance imaging (fMRI). MRI uses a strong magnetic field and radio waves to obtain
      images of body organs and tissues. The MRI scanner is a metal cylinder surrounded by a strong
      magnetic field. During the procedure, the subject lies on a stable that can slide in and out
      of the scanner, wearing earplugs to muffle loud knocking sounds that occur with electrical
      switching of the magnetic fields. Functional MRI involves taking MRI scans while the subject
      performs a task-this to learn about how the brain regions are involved in performing the
      task. For this test, the subject plays or watches two-person games involving trust. The game
      may be played against a stranger or a friend. The winner receives a cash payoff.

      The subject performs one of the following two tasks during MRI scanning:

        -  Playing the trust games and indicating as quickly as possible by pressing a right or
           left button whether he or she wants to stop or continue playing, or

        -  Observing games that others have played and predicting as quickly as possible by
           pressing a right or left button whether the players wanted to stop or continue the
           games.

      The test takes about 90 minutes. After the scan, participants complete written questionnaires
      about their experience in the scanner and their views on issues related to participating in
      competitive games.

      ...
    

Detailed description: 
      Objective. The purpose of the protocol is to identify the brain regions mediating the social
      cooperation involved in economic decision-making, including whether negative mood and
      perceived interpersonal similarity affect behavior or brain regions utilized.

      Study Population. Healthy, normal adult volunteers will play and observe two-person
      reciprocal trust games during functional neuroimaging against either real people or computers
      masquerading as real people.

      Design. A between/within-subject, rapid event-related fMRI design will be employed for two
      series of experiments. In the first experiment, two persons-each in a separate MRI
      scanner-will interact with one another playing two-person reciprocal trust games while their
      brains are simultaneously scanned. In the second experiment, a third person will later
      observe the played games while in a scanner, trying to predict the decisions of the two other
      players in the first experiment. In the third experiment, a sad mood will be induced in half
      of the participants to examine if it affects levels of cooperative behavior and patterns of
      brain activation in the two types of trust games described above.

      Four additional series of experiments will employ between/within subject designs in which
      subjects are scanned alone, but under the deception that they are playing simultaneously with
      another subject.

      Outcome Measures. The data collected will consist of behavioral measures of cognitive
      performance, self- and other-mental representation, trusting and trustworthy behavior,
      corresponding fMRI images, personality scales, ratings of relationship and status, and types
      of strategy used. The results gained from this protocol will be of value in identifying a set
      of neural regions mediating dynamic social interaction between people engaged in economic
      decision-making.
    

Keywords: PFC; Competition; Bargaining Games; Hyper-Brain Scanning; fMRI; Healthy Volunteer; HV