Figure 4.6 | Cumulative Record Illustrations of Acquisition, Extinction, and Spontaneous Recovery | (a) This is an acquisition cumulative record; the responding rate increases as learning occurs so the cumulative record has a fairly steep slope reflecting this increase. (b) This is an extinction cumulative record; the responding rate has essentially fallen to zero. A flat cumulative record indicates extinction. (c) This is an example of spontaneous recovery—a burst of responding following a break in extinction training. As the extinction training continues, the record will return to flat (no responding).