ABA Fundamentals

Rapid acquisition of preference in concurrent chains.

Grace et al. (2003) · Journal of the experimental analysis of behavior 2003
★ The Verdict

Pigeons rewired their choice in one day when food delays changed, so your learners can too.

✓ Read this if BCBAs who adjust token boards, break times, or reinforcement delays in classrooms or clinics.
✗ Skip if Practitioners working only with fixed, long-term schedules that never shift.

01Research in Context

01

What this study did

Six White Carneau pigeons pecked two keys in a two-link chain.

Each day the delay to food in the second link changed.

Birds had one 60-min session every day over the study period.

Researchers watched how fast the birds switched their first-link pecks when the wait times moved.

02

What they found

The pigeons changed their choice almost right away.

By the second day they matched their pecks to the new delays.

Sensitivity stayed strong for the whole two-month run.

Adjustment was a little sharper when the longer delay topped eight seconds.

03

How this fits with other research

Thomson (1974) already showed pigeons pause longer in the first link of chained FI schedules.

The new study adds that those pauses can flip overnight if the later delay shifts.

Blackman (1970) found pigeons gain stimulus control in two sessions.

Najdowski et al. (2003) now shows the same speed for whole schedule reallocation, stretching the idea from simple cues to full choice patterns.

Sponheim (1996) saw mixed results when pigeons picked between sure and risky delays.

The clean daily swings in C et al. hint that keeping stimulus colors constant helps birds track delay changes better.

04

Why it matters

If a client stalls when reinforcement is delayed, you can shrink the delay today and see change tomorrow.

No need to run weeks of retraining after each schedule tweak.

Try shifting token gain times, break lengths, or response requirements session-by-session and watch choice move with you.

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→ Action — try this Monday

Change the token-to-backup delay by two seconds and record if the learner’s button hits follow the new ratio by the next session.

02At a glance

Intervention
not applicable
Design
single case other
Population
other
Finding
positive
Magnitude
medium

03Original abstract

We report two experiments using a concurrent-chains procedure in which one terminal-link schedule was fixed-interval 8 s and the alternative schedule changed randomly from day to day. In Experiment 1, the alternative schedule varied between 4 s and 16 s according to a pseudorandom binary sequence similar to the one used by Hunter and Davison (1985). Similar to results with concurrent schedules, pigeons' response allocation in the initial link was most sensitive to the schedules arranged in the current session, although some effect of prior history was evident. Overall sensitivity was lower than for comparable data from steady-state research. In Experiment 2, a unique value between 2 s and 32 s was used for the alternative-schedule delay in each session. Sensitivity levels were similar to Experiment 1 and remained unchanged across 61 sessions of training. For all subjects, sensitivity was greater when the alternative-schedule delay was greater than 8 s compared with when it was less than 8 s. Generalized-matching plots revealed evidence of clustering of data points into two groups for some pigeons, suggesting that a process similar to a categorical discrimination may have at least partly determined response allocation. Overall, this research shows that pigeons' initial-link response allocation can adjust rapidly to frequent changes in the terminal links.

Journal of the experimental analysis of behavior, 2003 · doi:10.1901/jeab.2003.80-235