Figure 1.

Display of a trial in the intentional fair-alternative condition. The name of the proposer is shown at the top (here “Proposer”) and the name of the participant is shown underneath (here “You”). The two potential distributions are specified by red and blue coins (red for proposer, blue for responder), with the offer selected by the proposer encircled in red. Participants have to indicate via button press whether to accept (“Yes”) or reject (“No”) the offer. Note that for unintentional offers (not shown here), the otherwise black silhouette of the proposer was purple with a banner displaying “Computer chooses,” which was also depicted instead of the proposer's name.