A temporal parameter influencing choice between signalled and unsignalled shock schedules.

The team gave rats two levers. One lever led to shocks that came with a 5-second warning light. The other lever led to shocks with no warning.

They changed how often the shocks came. In one phase shocks arrived every 45 seconds. In another phase they came every 150 seconds or longer.

The rats could press either lever at any time, so the researchers watched which lever the rats picked most.

When shocks were 150 seconds apart or more, rats almost always picked the lever with the warning light.

When shocks were only 45 seconds apart, the rats flipped and picked the no-warning lever.

The longer the safe gap, the more the rats valued the safety signal. When the gap was short, escape was not worth the effort.

Liberman et al. (1973) showed rats will take eight times more shocks if each one is signalled. The new study adds a clock rule: the safety signal only wins when the break between shocks is long enough.

Lewis et al. (1976) ran a sister study the same year. They proved the safety cue itself must be trustworthy. Together the papers show both cue honesty and cue timing steer choice.

Wilkie et al. (1981) moved the idea to food work. A tone that marked shock-free periods kept rats pressing a food lever. The safety signal acts like extra reinforcement even when the main task is appetitive.

You can use safety signals in behavior plans. Before a loud vacuum, a brief countdown can cut problem escape. But keep the aversive event rare; if it comes too often the signal loses value. Try 3-minute clean cycles, not 30-second ones, and watch clients stay calmer.