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. 2022 Sep 13;13:961484. doi: 10.3389/fpsyt.2022.961484

FIGURE 1.

FIGURE 1

Intertemporal choice task and cognitive intervention paradigms. (A) During the intertemporal choice (ITC) task, the participants made choices between an immediate smaller reward and a delayed larger reward. The immediate reward was fixed (10,000 Korean Won, KRW), but the alternative delayed option was constructed using six distinct delays (1, 10, 21, 50, 90, and 180 days) and varying sizes of delayed rewards (10, 300–29, 300 KRW) determined by stepwise approach. Individuals could make a response when the crosshair turned red, and a feedback screen followed their choices to highlight the chosen option. (B,C) Two intervention tasks and their control tasks were used to examine the impacts of associative memory and working memory on future reward simulation and, in turn, on delay discounting. (B, left) The associative memory task comprised the encoding and retrieval phases (not depicted here). In the encoding phase, the participants were asked to memorize associations between the paired stimuli. Specifically, names of countries with a picture of their representative must-see sights were matched with “expected preparation time” to go on a trip to the places. Note that the preparation time was presented in the same format as the reward delays used in the ITC task (e.g., 10 days later). (B, right) The ControlAM was largely identical to the Associative memory task, except that the associations were made between country names and various stationaries. (C, left) In the working memory task, the participants had to remember a random three-digit number presented on the screen (e.g., 255), mentally subtract seven, and report the number on the subsequent screen (e.g., 248). They were asked to repeat this mental calculation (e.g., 241, 234, 237, …) until a new random number was provided. (C, right) During the ControlWM task, the participants had to maintain a sustained level of attention. Specifically, in each trial, a circle showed up on either left or right half of the screen, and the participants were asked to press the arrow key that matches the location as soon as possible.