Experimental Design
In the experiment, subjects complete 24 Gächter et al. (2016)’s ball catching tasks along with a digit recall task. In the ball catching task, subjects face 3 different incentive levels: (c,P)={(5,10),(10,20),(5,20)}. For the digit recall task, half of the tasks are completed under {low cognitive load where they must recall a 1-digit number, while the other half of the tasks are completed under high cognitive load where they must recall a number of digits determined by a pilot. The within-subject cognitive load treatment is administered in blocks: in the first half of the experiment (first 12 rounds), subjects will face high/low cognitive load; in the second half of the experiment (last 12 rounds), subject will face low/high cognitive load. The order of the high/low blocks presented to subject is randomized to account for ordering effects. We will recruit from a subject pool of students because they are more responsive to incentives and exclude anyone with a pacemaker due to the use of the GSR in our design. During the session, subjects will wear GSR to estimate their physiological arousal and EEG to estimate their cognitive load.
At the start of the experiment, subjects are randomly assigned between the additive and multiplicative treatment conditions which remains unchanged throughout the duration of the study. In the additive scheme treatment, the payment between the ball catching and the digit recall tasks are independent of each other; in the multiplicative scheme treatment, the payment in the digit recall task depends on the performance in the ball catching task. Specifically, subjects in the additive condition receive a fixed payment for correctly recalling the number in the digit recall task, while subjects in the multiplicative condition have their earnings in the ball catching task doubled if they correctly recall the number in the digit recall task.