Lever attacking and pressing as a function of conditioning and extinguishing a lever-press avoidance response in rats.

Hamm et al. (1978) worked with 32 lab rats. Half learned to press a lever to avoid shock. The other half got shock no matter what they did.

Next the team turned off the avoidance contingency for everyone. They kept giving random shocks so they could see which bites came from frustration versus pain.

Rats that first learned to avoid shock bit the lever twice as often as controls. The biting jumped as soon as the avoidance schedule started.

During extinction the biting dipped only after the researchers subtracted bites that were clearly triggered by the shock itself. Frustration bites faded; pain bites stayed.

Tracey et al. (1974) showed that human handwriting changes under schedule control, just like lever biting does in rats. Both papers treat response form as data, not noise.

Timberlake et al. (1987) ran competitive fixed-interval schedules with adult humans and saw the same break-and-run bursts that basic animal work predicts. The rat findings line up: schedule history shapes topography across species.

Borrero et al. (2005) added brain scans to operant work. Their frontal-striatal activation fits here: avoidance learning is strong, so extinction produces visible emotional fallout like biting.

When you fade escape or avoidance contingencies with a client, watch for new problem forms—hair pulling, object mouthing, or repetitive tapping. These are not random; they are extinction-induced topographies. Track them separately from sensory or pain-based responses. You will see clearer extinction curves and know your intervention is working before the emotional spikes vanish.