e., person or galaxy) was more highly ranked, and by how much (“control” trials: see Figure 5B). T2 weighted gradient-echo planar images (EPI) with BOLD (blood oxygen level-dependent) contrast were acquired on a 3.0 tesla Siemens Allegra MRI scanner using a specialized sequence to acquire whole-brain coverage, while minimizing signal dropout in the medial temporal lobe and ventromedial prefrontal cortex. High-resolution (1 × 1 × 1 mm) T1-weighted structural MRI scan were also acquired for each participant after functional scanning. Images were preprocessed and analyzed in a standard manner using the statistical parametric mapping software SPM8 (www.fil.ion.ucl.ac.uk/SPM).

Details of the parametric models used are given below: see Supplemental check details Information for full details of procedures used for model specification, estimation, statistical inference,

and ROI analyses. The following participant-specific trial-by-trial parametric regressors were included (in the order stated) in the first level design matrix relating to test trials (see Supplemental Information for specification of training trial, and other regressors www.selleckchem.com/screening/kinase-inhibitor-library.html also included in the model [e.g., movement parameters, etc.]): (1) Trial-by-trial reaction time (RT); (2) probability_correct: following previous studies (e.g., Kumaran et al., 2009) trial-by-trial estimates of the probability of a correct response derived from learning curves were constructed separately for each of the six test pairs (e.g., P2 P4) using the state-space model (Smith et al., 2004); (3) inference score (range 0–3; see above). All test trial types (i.e., six pairs: P2 versus P4, P2 versus P5, P2 versus P6, P3 versus P5, P3 versus P6, P4 versus P6) were modeled within these regressors, with one regressor for the person condition and one for the galaxy condition. We set up two different parametric models to detect brain regions whose activation pattern (1) exhibited a significant linear correlation with the maximum amount of money participants were willing to pay for

shares in a however project during bid trials (i.e., WTP) and (2) showed a significant linear correlation with the rank of person or galaxy in the hierarchy, during bid or control trials. The following vectors were then included as parametric modulators in the design matrix (in order): fMRI parametric model one—(1) trial-by-trial reaction time (RT), (2) WTP: participants’ stated maximum price that they were willing to pay for the shares in the project; fMRI parametric model two—(1) trial-by-trial reaction time (RT), (2) galaxy rank, (3) person rank. These parametric regressors were convolved with the HRF, leading to the height of the HRF for a given event being modulated accordingly. Thus, these regressors model BOLD signal changes that covary with specific behavioral indices of performance on a given trial (e.g., inference score during test trials in phase 1).