Interresponse time as a function of continuous variables: a new method and some data.

The author plugged an oscilloscope into a rat lever. Each press lit a dot. A camera left the shutter open, so dots piled up into a glowing ridge.

The picture shows every inter-response time (IRT) at once. Long pauses look like wide gaps. Quick bursts look like tight clusters.

Under DRL 10 s the ridge showed a sharp wall at 10 s. Rats rarely pressed sooner, but they bunched presses right after the pause.

When a tone signaled food, the wall moved. The visual shift took seconds to see, no math needed.

Gaucher et al. (2020) later used the same DRL idea with autistic preschoolers. Kids who talked well learned to wait; kids with low language did not. The 1963 camera trick shows why: the wall is invisible if you cannot hear or see the cue.

Logue (1983) offered a digital filter to smooth noisy rate graphs. Both papers give cheap ways to clean data and spot patterns without stats software.

Glover et al. (1976) found that richer food lengthens the pause after reinforcement. The camera picture would show that wall sliding right in real time, linking their numbers to a shape you can point to.

You can build this rig for under $50 with a used oscilloscope and a webcam. When a client’s response rate looks messy, one photo tells you if the schedule is working or if the pause is drifting. Use it to tune DRL, VR, or FI schedules in minutes instead of waiting for weekly summaries.