Behavioral aftereffects of reinforcement and its omission as a function of reinforcement magnitude.
Reinforcer size or omission in one activity can spike or drop behavior in the very next activity.
01Research in Context
What this study did
Jensen et al. (1973) worked with pigeons in a two-part schedule.
In Part 1 the birds pecked for food that came in different amounts.
In Part 2 the food was taken away.
The team watched how fast the birds pecked right after each change.
What they found
Bigger food in Part 1 made more pecks in Part 2.
Taking the food away made even more pecks — a contrast jump.
The size of the food and its absence both shaped later behavior.
How this fits with other research
Cicerone (1976) seems to disagree.
That study showed early food in a part can slow, not speed, later pecks.
The gap is timing: C et al. changed amount and omission, A moved food to the start.
Both prove the same rule — what happens in one part leaks into the next.
Sturmey (1995) adds a twist: longer parts dull the leak.
So short, rich parts create the strongest contrast waves.
Why it matters
Your client moves between activities like these pigeons move between parts.
If you just gave a big reinforcer, or had to skip one, expect a brief burst or drop in the next task.
Shorten the next part or add prompts to ride the wave safely.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →After a large or missed reinforcer, watch the first 30 s of the next task for sudden rate changes and insert a brief prompt or time delay to steady responding.
02At a glance
03Original abstract
Rats responded on a multiple fixed-interval fixed-interval schedule of reinforcement. Each complete cycle of the multiple schedule was separated from the next by a relatively long period of timeout from all schedule contingencies. A response at the end of the second component of each cycle was always reinforced with an invariant reinforcement magnitude, while reinforcement magnitude and reinforcement omission were systematically varied in the first component. Response rate in the first component was a monotonic function of reinforcement magnitude in that component. These changes in response rate in the first component did not affect response rate in the second component. When reinforcement was omitted on 50% of occasions in the first component, following reinforcement there was a reduction in response rate in the second component that was monotonically related to reinforcement magnitude. Following reinforcement omission there was an increase in response rate in the second component that was unrelated to reinforcement magnitude. When reinforcement was omitted on 100% of occasions in the first component, behavioral contrast was observed.
Journal of the experimental analysis of behavior, 1973 · doi:10.1901/jeab.1973.19-459