Counting by Humans on a Fixed-ratio Schedule of Reinforcement.
In a series of experiments on observing behavior (2, 3), a subject is asked to monitor a dial and report deflections of a pointer. The dial is in the dark and can be seen only by pressing a key which briefly flashes a light. This response on the light-flashing key is defined as an observing response since it is essential for detecting the signal. The work has demonstrated that signal detections reinforce the observing response.