 Subjects will perform two different tasks, one representing a typical laboratory L, one an everyday-like task E. In task L, a visual stimulus on the screen will prompt subjects to release the joystick, grasp the lever, move it forwards and back, and then return their hand to the joystick. In task E, subjects will use the joystick in a computer game spider chasing and occasionally release the joystick, grasp the lever, move it forwards and back in order to collect a reward, and then return their hand to the joystick. In both tasks the visual stimuli are accompanied with acoustic signals. To hear these signals during the flight procedure, subjects are equipped with ear-phones, plugged into a laptop. 