Fig. 2.

Time line of the experiment. A fixation cross marks the inter-trial interval which lasts between 1.5 and 4 s, after which a screen depicting the PD appears. Six seconds later, an indicator appears and stays on the screen for an additional 2 s, signaling the end of the participants’ allotted time to make a decision. The decision phase can end earlier when one of the buttons is pressed. In between the decision phase and the feedback phase a screen appears for 2–4 s asking the participant to wait. The feedback phase starts when the screen revealing the partner response is shown, which lasts 3 s.