BEHAVIORAL CONTRAST DURING MULTIPLE AVOIDANCE SCHEDULES.

The team set up two back-to-back avoidance schedules. In one part shocks came rarely. In the other part shocks came often.

They watched how the animal’s lever-pressing shifted when they changed the shock rate in just one part.

Pressing moved in step with shock chance. When shocks got rarer in part A, pressing sped up in part B.

This is behavioral contrast: change one schedule, see the opposite jump in the other.

Baron et al. (1966) split the jump into two steps. Right after the switch the jump is big, then it fades. The 1965 paper saw the same jump but did not time it.

Wright (1972) added math. He showed the jump follows Herrnstein’s matching rule. Shock reduction acts just like food reinforcement.

Scull et al. (1973) set a limit. Contrast only shows up if the same response is used in both parts. Switch the response form and the effect vanishes.

Your client may run multiple programs—DTT then play, or work then break. If one part gets easier, you may see a spike or drop in the other part. Watch for these swings. Keep the target response similar across parts to let the contrast help you, not hurt you.