Balloon Analog Risk Task (BART)

The BARTis an incentive-compatible computerized measure of risk-taking behavior where participants are presented with a series of balloons and can earn money as they pump up the balloons (Lejuez et al., 2002). For each balloon participants earn a fixed amount per pump. However, as with real balloons, the balloons will burst at some unbeknownst point. In this case the earnings for this particular balloon are lost and the next balloon is presented. Alternatively, participants can choose to stop pumping up the balloon, “bank” the earnings and move on to the next one. While participants are told that the individual balloons will pop at different points, the actual probability distribution is not revealed. Each participant's pay-out for the task depends on the sum of the size of the balloons that did not pop, and risk tolerance is calculated for each participant as the average number of pumps for the balloons that did not pop. This is also known as the Adjusted BART Score. In our study participants are presented with a total of 20 balloons and can earn GBP 0.01 per pump. Their total earnings are calculated after the game and are paid out to the participant with a 1 in 20 chance.