Forty-two male participants took part in this experiment (aged 18-31, mean age 23.1 years). The study was approved by the local Research Ethics Committee. Functional images were acquired on a 3T Siemens Allegra scanner using a gradient-echo EPI pulse sequence. Imaging data were analyzed with SPM5 (www.fil.ion.ucl.ac.uk/spm/), including standard preprocessing procedures (spatial realignment, correction for differences in slice acquisition time, spatial normalization and smoothing) and modelling the data by a set of general linear models. During the virtual reality task, participants were presented with a first-person perspective of a grassy plane surrounded by a circular cliff. Participants moved the viewpoint by using their right hand to operate keys to move forward and turn left or right. Throughout the experiment, participants collected and replaced everyday objects within the arena. See methods and ref.11 (link) for details.