I plan to present mp3. files that play music clips in the left ear, and a spoken word recording in the right ear. The participants will be instructed to only pay attention to the spoken word, and press a key every time they hear the word 'and' being said. I would like to keep track of how many times they press a key. The sound file is about 12 minutes long and the number of times that each participant will press a key will obviously vary. It would also be good if they were given feedback when they do press a key like a beeping sound or a brief visual. Is this possible to do? and if so please provide me with some specific details? Thanks