Hi there,
I am working on a variation of the stop-signal task wherein participants see an arrow pointing one direction and respond with the corresponding button (left or right). However, I would like on a quarter of the trials for there to be a “change signal” - a beep that plays after a delay (either 100 or 250ms) while the arrow is on the screen. When this beep is played the participants should change their response to the opposite so that a left arrow + beep = right button press.
I’ve been trolling the forums to see if anyone has come across a solution and can’t seem to find an answer that works exactly. Any suggestions? Thank you 
- Matt