Acquisition and maintenance of postshock response pattern in nondiscriminated avoidance with rats.

Berler et al. (1982) worked with five rats in a small lab chamber. Each rat could press a lever. If the rat pressed, it got a short break before the next shock. If it did nothing, shock came faster. The team watched to see if the rats learned a steady pattern of pressing right after each shock.

The setup is called nondiscriminated avoidance. No lights or tones told the rats when to respond. Only the shock timing changed based on what they did.

Four of the five rats quickly showed a clear post-shock pattern. They pressed the lever soon after each shock and kept the pattern going for the whole session. The fifth rat never settled into a rhythm.

The steady pattern shows the lever pressing was operant, not just a reflex kick after shock.

HERRNSTEISLOANE (1964) once saw the opposite: shock punishment made rats press more, not less. The two results look like a clash, but the schedules differ. In 1964 every press produced immediate shock — a punishment contingency. In 1982 pressing delayed the next shock — an avoidance contingency. Same shock, different rule, different outcome.

Bernal et al. (1980) showed that monkeys with a long avoidance history would even press when shock was delivered on a fixed timer. Their study came first and helped prove that shock history, not just the current rule, shapes later behavior.

Gardner et al. (1977) pigeons kept pecking even when the experimenters tightened the screws — shorter delays, more shocks. Together these papers say: once avoidance starts, it is hard to stop, no matter the species or response form.

For BCBAs the lesson is timing. A consequence that looks harsh can strengthen behavior if it buys the client even a brief break from something worse. When you design escape or avoidance programs, check the seconds between response and aversive event. A tiny delay can lock in the response, just like the rat’s post-shock lever press. Use that power carefully and measure whether the new pattern truly helps the client day-to-day.