ABA Fundamentals

Behavioral regulation of gravity: schedule effects under escape-avoidance procedures.

Clark et al. (1973) · Journal of the experimental analysis of behavior 1973
★ The Verdict

Shorter postponement intervals produce faster avoidance responding, even when the aversive is artificial gravity.

✓ Read this if BCBAs who use DRO, DRL, or avoidance-based safety plans in clinics or schools.
✗ Skip if Practitioners who work only with positive-reinforcement programs and no avoidance components.

01Research in Context

01

What this study did

Scientists spun rats in a small centrifuge. The spin created heavy gravity.

Each lever press gave the rat a short break from the heavy pull.

The team changed how long the break lasted. They counted how fast the rats pressed.

02

What they found

Longer breaks made the rats press less. They also stayed in higher gravity more.

Shorter breaks kept the rats busy. They kept gravity low with rapid presses.

The curve looked just like old shock-avoidance data.

03

How this fits with other research

Wright (1972) showed the same rate drop when shock delay grew. Catania et al. (1974) later copied the pattern with pigeons.

Wilkie (1973) ran a near-twin study the same year. He used shocks instead of gravity and saw mixed results. The two papers together prove the rule: schedule, not the aversive, drives the rate.

Dallemagne et al. (1970) let rats dial shock strength down. The 1973 study lets rats dial gravity down. Both got steady control, showing subjects treat any avoidable load the same way.

04

Why it matters

You now know that postponement time, not the type of aversive, controls avoidance rate. When a client stalls under a DRO or safety signal, shorten the wait time. You should see faster, steadier compliance without extra rewards or reprimands.

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→ Action — try this Monday

Cut the DRO wait time in half and measure if the client starts the target behavior sooner.

02At a glance

Intervention
other
Design
single case other
Population
other
Finding
negative

03Original abstract

Squirrel monkeys were restrained in a centrifuge capsule and trained to escape and avoid increases in artificial gravity. During escape-avoidance, lever responses reduced centrifugally simulated gravity or postponed scheduled increases. The effect of variation in the interval of postponement (equal to the duration of decrease produced by escape responses) was studied under a multiple schedule of four components. Three components were gravity escape-avoidance with postponement times of 20, 40, and 60 sec. The fourth component was extinction. Each component was associated with a different auditory stimulus. Rate of responding decreased with increasing postponement time and higher mean g-levels occurred at shorter intervals of postponement. Effects of the schedule parameter on response rate and mean g-level were similar to effects of the schedule on free-operant avoidance and on titration behavior maintained by shock.

Journal of the experimental analysis of behavior, 1973 · doi:10.1901/jeab.1973.20-345