1. Department of Management and Engineering , Division of Economics, Linköping University, 581 83 Linköping , Sweden
2. Center for Social and Affective Neuroscience , Department of Biomedical and Clinical Sciences, Linköping University, 581 83 Linköping , Sweden
3. Center for Medical Image Science and Visualization (CMIV) , Linköping University Hospital, 581 85 Linköping , Sweden