Fig. 1. Behavioral task and variables.

a Timeline of the task. On each trial, an option (presented as one of four different aliens) approached one of two targets. Participants decided to accept the option by selecting the target the option approached (right target in this example) or reject the option by selecting the alternative target (i.e. the target the option did not approach, left target in this example). When options were accepted, the selected target changed color to red and participants were required to maintain a key press during which the option expanded within the target. The target then changed color to yellow indicating that participants could release the key press and the number of points obtained was displayed represented as a partially filled horizontal bar. When options were rejected, the experiment immediately progressed to the next trial. b On each trial, participants encountered one of four possible options each of which provided either a low/high reward (points, later converted to a bonus payment) but also incurred either a short/long opportunity cost in the form of a time delay. c The experiment was divided into two blocks (environments) and the frequency of the four different options varied in each of these. There was a rich environment in which the best option (low delay, high reward) outnumbered the other three options and a poor environment in which the worst option (high delay, low reward) outnumbered the other three options. The order of the blocks was counterbalanced between participants. Stimuli were designed by Sahua (https://www.123rf.com/profile_sahua) and are copyrighted property of 123RF Limited.