ABA Fundamentals

Reinforcement of behavioral patterns: shaping a scallop.

Hawkes et al. (1975) · Journal of the experimental analysis of behavior 1975
★ The Verdict

Reinforcers can lock in entire 5-second response patterns when each phase is clearly cued.

✓ Read this if BCBAs teaching timed motor routines or smooth skill chains.
✗ Skip if Clinicians working only with simple discrete responses.

01Research in Context

01

What this study did

Green et al. (1975) worked with three pigeons in a small lab chamber.

The birds had to change their pecking speed in a set way across each 5-second trial.

If the pattern matched the goal, the pigeon got grain.

The goal was a smooth scallop: slow start, fast middle, slow end.

02

What they found

After a few sessions every bird produced the scallop shape.

Their patterns had less wobble than birds on a regular fixed-interval 5-s schedule.

Reinforcers strengthened the whole 5-second pattern, not just the last peck.

03

How this fits with other research

Russo et al. (2019) later used the same shaping logic to help teens with autism eat new foods.

They set tiny bite goals and raised the bar each meal, just like the pigeons’ peck-rate steps.

Eisenmajer et al. (1998) seems to disagree: unsignaled 3-second delays hurt pigeon responding.

The key difference is signaling. L et al. told birds exactly when the delay clock started, keeping the pattern clear.

04

Why it matters

You can reinforce smooth, time-based behavior patterns, not just single responses.

Try shaping a client’s 10-second tooth-brushing rhythm or a 5-second hand-washing sequence.

Set clear cues for each phase and reinforce the whole pattern when it looks right.

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→ Action — try this Monday

Film a 5-second target routine, split it into three parts, and deliver praise only when the whole sequence matches the goal shape.

02At a glance

Intervention
shaping
Design
single case other
Population
other
Finding
positive
Magnitude
large

03Original abstract

Temporal patterns of key pecking by pigeons were shaped by a schedule in which the delivery of food was contingent upon a measure of the overall extent to which the temporal pattern of behavior within a 5-sec trial conformed to a required pattern. This pattern approximated a constant rate of change in the rate of key pecking throughout the 5-sec trial. In comparison with behavior maintained by a classical fixed-interval 5-sec schedule, the new schedule controlled a better approximation to a "scallop" within individual trials and greatly reduced intersubject variability. These results are consistent with the view that the delivery of a reinforcer after a behavioral pattern a few seconds in duration may strengthen the entire pattern as a unit, or operant. The response topography contiguous with reinforcement may be a negligible fraction of the strengthened operant. One implication of this view is that mean response rate for such brief responses as key pecks and lever presses is a byproduct of whatever patterns are strengthened, and generally will not reveal fundamental controlling relationships, whenever a reinforcer is not contiguous with all the behavior on which it is contingent.

Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.23-3