counting multiple responses

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

Here is one way you could do it. Play the sound file as your first stimulus. Then--on the SAME trial--list 20 (or however many you like) pairs of stimuli like this:

~ | 0,0,1 | rt:57,28>-2
~spacebar! | 0,0,1 | 500

Where trial 2 is the next trial for example. In this case, the spacebar (keycode 57) will advance them every time to the next stimulus on the trial--after briefly seeing "spacebar!" appear. However, if they press ENTER then they will be immediately skipped out of the trial. Somehow you would need to instruct them to do that when the sound file has finished. Otherwise, the trial would never end unless the subject were to press the spacebar as many times as possible--in this example, 20.

Let me know if you have trouble with it!

thank you, that works well. Just one more question... how do I set the file up so that the participant listens to a story, responds every time they hear the word 'and' being presented and at the same time view a randomized group of visual stimuli. Each stimuli would be presented for 3 seconds and would be preceeded with a '+' for 2 seconds.

DirectRT doesn't do multi-tasking like that very well--especially for multi-stimulus, multi-response tasks where the number of responses per stimulus may vary. You could set something like that up in MediaLab though--is that a possibility for you?