Meaningful responding includes more than thinking or writing words; likewise, feedback comes in many other forms besides KCR. A programed text leading learners through steps in performing a chain task such as setting up audiovisual equipment can describe the step to be performed and the feedback that should occur when the act is performed correctly. One part of mastering a chain is leaming to discriminate the real feedback that signals that the step was done correctly. In the following bit of instruction, students are in the middle of getting a Carousel projector up and running. In the preceding step of the chain, they've put slides in the tray in the numbered slots, so there is a slide in #1 slot, and they've positioned the tray onto its bed on the projector. The response is easy to describe: Press the button. How do they know they've pressed the right button hard enough? What's the feedback they're to watch for from that response