FMRI Brain Scan

That data was collected by the Freie Universität Berlin and consist of 19 fMRI brain scans (dataportfolio/s101, s102,..., s124.nii ) of different subjects (1,2,3,4,5,6,7,8,9,11,13,14,16,17,18,19,21,23,24; few subjects excluded due to extensive head movements and different stimulus frequency). Each nii file, e.g., s101.nii, is a structure with a time series (1400 observations) of 3-dimensional matrix that represents the BOLD signal (Blood-oxygen-level dependent) during the investment decision experiment. The mask file is the corresponding brain mask, indexed foe/text files are the experiment log files and dec_sd.foe is a stimulus time table.

Investment Decision experiment:

Subjects (n=19) performed an adjusted version of the Risk Perception in Investment Decisions (RPID) Task (Mohr et al., 2010). In this task subjects see past returns of either one single investment or two investments that form a portfolio (50% of the money invested in each). While they see the past returns they have to make a choice if they would prefer investing in a bond with 5% fixed return or the investment that is displayed (either single risky investment or risky portfolio). The choice situations differed in three within-subject conditions: (I) choices between 5% fixed return and a single risky investment, (II) choices between 5% fixed return and a risky portfolio of 2 single investments with correlated returns (r=1), and (III) choices between 5% fixed return and a risky portfolio of 2 single investments with uncorrelated returns (r=0). Importantly, the return history of the risky options (either single investment or portfolio) was exactly the same in all 3 conditions. We varied both expected returns and standard deviations of the risky investments parametrically with 4 expected returns (6%, 8%, 10%, 12%) and 4 standard deviations (2%, 4%, 6%, 8%). Each of the choices regarding single investments was repeated once to hold the number of choices between the bond and a single investment and the bond and a portfolio constant. In total subjects made 256 choices in two blocks of 128 choices each. Subjects had a maximum of 7 seconds to enter their choices via a response box with two buttons. The location of the choice options on the screen was counterbalanced between left and right to avoid order effects.