Choice of longer or stronger signalled shock over shorter or weaker unsignalled shock.

The team let rats pick between two shock schedules. One schedule gave a brief warning light before every shock. The other gave no warning.

The catch: the warned shocks could last nine times longer or feel three times stronger. The rats could not escape any shock. They simply chose which schedule to face.

Every rat chose the warned shocks almost every time. Predictability beat pain. A long, bright warning followed by a bigger shock felt safer than a surprise jolt.

Liberman et al. (1973) ran the same choice set-up but raised shock density instead of length. Rats still picked the signalled side, showing the rule holds across different price tags.

Glover et al. (1976) later found a boundary: when shocks came every 45 s the preference flipped. At short intervals the warning loses value because "safe" time is too brief.

Lewis et al. (1976) mixed the signals. They showed the deciding factor is not the danger cue but a dependable safety cue that reliably says "all clear." Together the papers say: animals do not want milder pain; they want a clock that tells them when pain is over.

Your learners cannot escape every aversive event—loud bells, medical shots, fire drills. Giving a clear, timed warning before the event and a clear end signal afterward can cut problem behavior more than reducing the intensity. Use visual timers, countdown strips, or first-then boards to supply the safety signal. The forecast, not the shock, is what soothes.