Fig. S1.

Experiment S1. (A) Experimental design. All participants (15 healthy adults) performed four 15-min sessions of an executive task (switching between discrimination tasks depending on a contextual cue), each followed immediately by a 1-min series of 16 intertemporal choices (IC). (Lower) Easy and hard versions of task switching (one versus 105 switches in a session) were always alternated in the order shown on the timeline and were separated by a 1-min break. (Upper) For the executive task a series of different letters was displayed on screen, each starting a new trial. Participants had to categorize the current letter into either vowel versus consonant or uppercase versus lowercase, depending on its color. At the end of the session participants made self-paced choices between immediate and delayed monetary rewards. (B) Behavioral results. Graphs show the sessionwise percentage of correct trials in the executive task (Left) and the percentage of impulsive choices, defined as the choice of immediate reward (Right). Dots represent means, and error bars are intersubject SEs. There was no difference in choice impulsivity between sessions or between difficulty levels.