A Diagram of the Skilled Task (IMAGE) Johns Hopkins Medicine Caption 'X' is the start position. The object of the task is to move both dots into the square within two seconds. This is challenging, because moving the cursor only controls the green 'ball;' the yellow 'ball' is attached to it via a virtual spring. When you move your hand toward the target, the yellow ball oscillates. Credit Vikram Chib, Johns Hopkins Medicine Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.