Fig 1. Child-friendly reward task.

Participants were instructed to select one of two facedown cards to flip for a win, loss, or no change in points (neutral). The magnitude of the reward or loss could be large or small. Each block consisted of 4 identical and 1 incongruent trial. There were a total of 18 blocks; 3 blocks of large win, 3 blocks of small win, 3 blocks of large loss, 3 blocks of small loss, and 6 neutral blocks. Each set of 6 blocks occurred on a different island (turtle, parrot, monkey). Total run time of the task lasted approximately 10 minutes. (a) Original version of the reward task for spiral acquisition. The two facedown cards were displayed for up to 3000 ms. After the card flipped, one of three images appeared for 1000 ms: genie (win), pirate (loss), or palm tree (neutral). Feedback on the magnitude of the reward (large or small) was provided for 1000 ms. (b) Modified version of the reward task for multiband acquisition. The two facedown cards were displayed for 1000 ms. After the card flipped, an image of a genie (win), pirate (loss), or palm tree (neutral) was displayed for 1000 ms. Feedback on the magnitude of the reward (large or small) was provided for 1000 ms.