Immediate values for different trials in the Intertemporal Choice Task
| Immediate Relative Value | Total trials | Description |
|---|---|---|
| Immediate Subjective Value lower than Delayed Subjective Valuea | 32 | Magnitude of immediate option is below immediate equivalent (i.e., immediate value at indifference point). There were four different percentage distances below the immediate equivalent (−10, −20, −35, and −50%). Subjects who receive sham stimulation should choose the delayed option if the choice is for gains and the immediate option if the choice is for losses. |
| Immediate Subjective Value equal to Delayed Subjective Value | 8 | Magnitude of immediate option is equal to immediate equivalent (i.e., percentage distance is 0%). Neither immediate nor delayed choice is predicted for sham group. |
| Immediate Subjective Value higher than Delayed Subjective Value | 32 | Magnitude of immediate option is above immediate equivalent. There were four different percentage distances above the immediate equivalent (10, 20, 35, and 50%). Subjects who receive sham stimulation should choose the immediate option if the choice is for gains and the delayed option if the choice is for losses. |
Each delayed gain and each delayed loss magnitude was shown nine times. Each delayed option was paired once with an immediate option located at each of the nine percentage distances from the immediate equivalent of the delayed option. Values at negative distances were taken as a function of the percentage difference between the immediate equivalent and zero. For example, a −35% distance indicated that the magnitude of the immediate option was 35% less than the immediate equivalent. Values at positive distances were calculated as a function of the percentage difference between the immediate equivalent and the delayed option. For example, a 35% distance indicated that the magnitude of the immediate option was greater than the immediate equivalent by 35% of the distance between the immediate equivalent and the magnitude of the delayed option.
↵aFor both monetary gains and losses, immediate relative value positively scaled with magnitude.