Facilitation and suppression of responding under temporally defined schedules of negative reinforcement.

The team built a shock-avoidance box for lab animals. They first gave shocks at steady times no matter what the animal did. Then they switched to rules where each response changed when the next shock could come. They watched speed of lever pressing across these shifts.

The goal was to see if behavior speeds up or slows down when the shock rule changes from pure time-based to response-linked.

At first, animals pressed faster when shocks became tied to their responses. After more exposure, the same animals slowed their pressing below the starting rate. The switch point moved with how often the shocks were programmed.

So the same shock schedule first helped, then hurt, the very behavior it was meant to maintain.

Zimmerman (1969) saw steady rate increases when shocks arrived on fixed-interval time only. Wilkie (1973) shows that adding response-dependence flips the long-term effect from boost to drop. The two studies do not clash; they map different parts of the same curve.

Kelleher et al. (1969) used an interlocking postponement schedule and also got rising then falling rates. Their pattern supports M's claim that rate change direction hinges on how response and time intertwine.

Sachs et al. (1969) punished every avoidance response and saw quick suppression. Wilkie (1973) shows you can get the same suppression without extra punishment—just by letting the avoidance schedule itself run long enough.

If you use escape or avoidance procedures with clients, watch for a honeymoon phase where behavior looks great, then a slump where it fades. The schedule, not the aversive, is driving the swing. Track data past the first few sessions and be ready to thin or reshape the contingency before suppression sets in.