A rate measure of the relative aversiveness of signalled vs unsignalled shock.

Macdonald et al. (1973) worked with rats in a two-link chain schedule.

A light or a tone warned some shocks were coming. Other shocks arrived with no warning.

The team counted how fast the rats pressed a lever. Slower pressing meant stronger fear.

Rats pressed much slower when no signal came before shock.

With a signal, pressing stayed higher. The signal made the same shock feel less bad.

The drop in rate gave a clean number for how aversive each shock type was.

Hymowitz (1976) saw the same thing, but only when the signal and shock were in a multiple schedule. In a mixed schedule the signal helped less. The two studies line up once you know the schedule type.

Hamilton et al. (1978) added a twist: foot shock with a signal first slowed, then sped up, wheel turning. Tail shock only slowed it. The 1973 paper showed the basic suppression; the 1978 paper showed the body part can flip the later effect.

Davis et al. (1976) put the signal after shock or on both sides. Signal-shock-signal kept the most baseline pressing. Their work extends the 1973 finding by showing timing, not just presence, of the cue matters.

You can soften unavoidable bad events by giving a clear, early cue. A two-minute timer before a loud drill, a hand raised before a sharp instruction, or a picture card before a dentist tool can all cut the behavioral shutdown you see. Try adding a brief, consistent signal the next time a client must face something unpleasant but unavoidable. Measure the response rate before and after you add the cue; if it drops less, you have cheap, fast evidence the cue is helping.