Instructor pilot fails to recognize the student pilot made a touch and go on the wrong parallel runway.

Narrative

Entered left traffic pattern from training area. Student flying in left seat. Tower cleared us for the option 4 Right. Acknowledged clearance. Student stated she did not clearly hear tower so I repeated tower clearance to 4 Right. Then made a nice pattern to touch and go on 4L. On the go Tower advised us our clearance was to 4R. My answer was 'Good Grief.' No other traffic in the patterns or on the surface. Beautiful CAVU morning; very light quartering tailwind; familiar with the airport etc. etc. Possible causes: I think I must have been expecting 4L from the start because this is the usual procedure; but I heard and repeated 4R. Most terrible example to the student. Student not yet soloed; and still in the trusting the instructor for everything stage. I am a high time airline pilot who does not fly much VFR at all and lands off an ILS on almost every approach. However; I have had to go-around a few times in my career when a small airplane pulled in front of me lining up on my runway instead of the parallel. Somehow I managed to negate years of training and experience to make such a serious mistake. I had better relearn how to think for myself. There is absolutely no excuse for this.