ABA Fundamentals

Schedules using noxious stimuli. I. Multiple fixed-ratio and fixed-interval termination of schedule complexes.

Morse et al. (1966) · Journal of the experimental analysis of behavior 1966
★ The Verdict

Schedule structure, not whether the reinforcer is nice or nasty, shapes the response pattern.

✓ Read this if BCBAs writing negative-reinforcement protocols or studying basic schedule control.
✗ Skip if Clinicians who only use edible reinforcers and never touch escape contingencies.

01Research in Context

01

What this study did

The team set up FR and FI schedules with squirrel monkeys.

Each response turned off a mild electric shock for a set time.

They watched whether the animals still showed the usual FR burst and FI scallop even though the reinforcer was escape, not food.

02

What they found

The monkeys produced the same burst-and-pause under FR and the same curved line under FI.

Schedule shape, not snack versus shock relief, controlled the pattern.

03

How this fits with other research

McKearney (1970) ran the mirror test: shock delivery instead of shock escape.

Same FR burst and FI scallop appeared, backing the idea that schedule structure rules.

Hamilton et al. (1978) went further, letting one key give shocks and another stop them.

Both responses kept going, showing positive and negative reinforcement can live side-by-side.

Branch et al. (1981) seems to clash: ratio schedules hurt responding when shocks are given, not removed.

The gap is in the contingency—delivery punishes, termination reinforces—so ratio size matters only when the consequence is aversive delivery.

04

Why it matters

If you run escape or avoidance programs, think schedule first, reinforcer second.

A DRO or DRL will scallop, and an FR 5 will burst, whether the payoff is candy, break time, or leaving a loud room.

Pick the schedule that gives the pace you want; the valence of the reinforcer is secondary.

Free CEUs

Want CEUs on This Topic?

The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.

Join Free →
→ Action — try this Monday

Plot your client’s response pattern on an FI 30-s escape schedule and look for the scallop—if it curves, schedule control is strong.

02At a glance

Intervention
other
Design
single case other
Finding
positive

03Original abstract

The termination of a schedule complex, comprising a stimulus in the presence of which brief presentations of electric shocks are scheduled, is a reinforcer. Conditions were studied under which schedule-controlled patterns of responding characteristic of fixed-interval, fixed-ratio, and multiple fixed-interval fixed-ratio schedules can be maintained in the squirrel monkey by terminating a schedule complex. The schedule of shock presentation was a critical determinant of the patterns of responding, especially under fixed-interval schedules of termination. The rates and patterns of responding under various schedules of termination of schedule complexes were generally akin to those maintained under comparable schedules of food presentation. The findings suggest a general similarity in the dynamic aspects of performances under schedules of schedule-complex termination and comparable schedules of food presentation. The schedule of reinforcement is more important than the nature of the reinforcer in the control of behavior.

Journal of the experimental analysis of behavior, 1966 · doi:10.1901/jeab.1966.9-267