Behavioral contrast with timeout, blackout, or extinction as the negative condition.

The team worked with pigeons in a lab. Birds pecked a key for food on a variable-interval schedule.

Sometimes the key light stayed on but food stopped. Other times the room went dark or the bird got a brief timeout.

The question: does contrast still appear if the bad period never lets the bird respond?

Pecking jumped higher in the food component when timeout or blackout followed it. Plain extinction did the same.

The boost happened even when the birds could not peck during timeout or blackout. Aversiveness, not just missed food, drives contrast.

Rogers-Warren et al. (1976) saw the same jump using only signaled extinction. Together the papers show the effect is real whether the bad patch is dark, timed-out, or just food-free.

Ginsburg et al. (1971) proved longer extinction gives bigger contrast. Sadowsky (1973) adds that the type of negative patch matters less than its presence.

Whalen et al. (1979) later repeated the pattern in three-month-old babies. The leap from pigeons to infants tells us contrast is a basic learning rule, not a bird quirk.

When you run multiple schedules or mixed programs, know that any aversive component—timeout, lights-off, or extinction—can spike responding in the reinforced one. Plan for these bursts. Monitor rates closely after you introduce a break, time-out, or non-reinforced task. Expect bigger contrast if the client just left a long extinction period. Use this knowledge to set safe rate ceilings and to praise calm, steady responding when the schedule changes.