Elicited responding to signals for reinforcement: the effects of overall versus local changes in reinforcement probability.
Schedule length decides whether learners track overall odds or tiny local changes.
01Research in Context
What this study did
Pigeons pecked a key that lit up before food.
The team changed two things: how long each session lasted and how often food came.
Short 30-second blocks showed one pattern. Long 3-minute blocks showed another.
What they found
In short blocks, the birds watched the overall odds of getting food.
In long blocks, they watched the tiny changes right after the light came on.
Same birds, same room, but schedule length flipped what controlled their pecking.
How this fits with other research
Dews (1978) ran the same setup two years later and saw the same flip.
Parsons et al. (1981) later said "not so fast"—they only saw the flip after they removed sneaky extra food.
Iwata (1993) then showed the flip also depends on whether the birds can see both choices at once.
Together, the four papers say: schedule length matters, but so do hidden food and choice layout.
Why it matters
When you set up a token board or visual timer, the length of each chunk changes what the learner tracks. Short chunks make them watch the whole board. Long chunks make them watch the last few seconds. Test both lengths to see which drives better behavior for your client.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Run the same task in 30-second and 3-minute blocks and count which one gives steadier responding.
02At a glance
03Original abstract
Pigeons were studied on a three-component multiple schedule where all reinforcement was independent of responding. Two components were cued by different keylights and were associated with different rates of reinforcement. The third was always a no-key period associated with extinction. After a few sessions, pecking was elicited by the keylights signalling the reinforcement and continued to be maintained indefinitely. The duration and sequence of the three components were varied to determine if the primary controlling variable was differences in the overall probability of reinforcement, or if it was the immediate change in reinforcement signalled by the onset and/or offset of the stimulus. Both variables were found to control behavior. When 30-sec components were used, the primary controlling variable was the overall probability of reinforcement, but when 3-min components were used, overall probability had little effect. Control by local changes in reinforcement also occurred, although the type of local control varied both across subjects and experimental conditions. Some behaviors were controlled more by the change in reinforcement signalled by the onset of the stimulus, while others were controlled more by the change signalled by the offset of the stimulus.
Journal of the experimental analysis of behavior, 1976 · doi:10.1901/jeab.1976.26-213