ABA Fundamentals

Confirmation of linear system theory prediction: Changes in Herrnstein's k as a function of changes in reinforcer magnitude.

McDowell et al. (1984) · Journal of the experimental analysis of behavior 1984
★ The Verdict

Bigger reinforcers raise the ceiling on response rate under VI schedules, just as linear system theory says.

✓ Read this if BCBAs who write VI or VR programs for teens or adults in clinic or vocational settings.
✗ Skip if Clinicians working only with fixed-ratio token boards where magnitude is already large.

01Research in Context

01

What this study did

The team tested eight adults with no disabilities. Each adult pressed a button for liquid reinforcers on a variable-interval schedule.

They changed the size of the liquid payoff across conditions. Then they tracked how fast the adults pressed the button.

02

What they found

Seven of eight adults showed the same pattern. Bigger payoffs lifted the top line of Herrnstein’s hyperbola.

In plain words, larger reinforcers pushed the maximum response rate higher. Linear system theory predicted this climb and the data matched it.

03

How this fits with other research

Tyrer et al. (2009) later saw the same climb on progressive-ratio schedules. Bigger sucrose pellets made rats work harder and break later.

Levin et al. (2014) added a new twist. They showed that larger reinforcers also protect behavior against extinction and pre-feeding.

Harzem et al. (1978) seems to disagree at first glance. They found that bigger payoffs lengthen the pause right after reinforcement. The two papers differ because P watched the quiet moment after delivery while J watched the overall rate across the whole session.

04

Why it matters

You now have a dial to turn. Increase reinforcer size when you want faster, more persistent responding. Watch for the brief pause that may follow; it is normal and does not cancel the rate boost. Use this when shaping new skills or when thin schedules start to drag.

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→ Action — try this Monday

Increase the size or duration of your edible or token payoff by fifty percent and count responses for ten minutes to see the rate jump.

02At a glance

Intervention
not applicable
Design
single case other
Sample size
8
Population
neurotypical
Finding
positive

03Original abstract

Eight human subjects pressed a lever on a range of variable-interval schedules for 0.25 cent to 35.0 cent per reinforcement. Herrnstein's hyperbola described seven of the eight subjects' response-rate data well. For all subjects, the y-asymptote of the hyperbola increased with increasing reinforcer magnitude and its reciprocal was a linear function of the reciprocal of reinforcer magnitude. These results confirm predictions made by linear system theory; they contradict formal properties of Herrnstein's account and of six other mathematical accounts of single-alternative responding.

Journal of the experimental analysis of behavior, 1984 · doi:10.1901/jeab.1984.41-183