ABA Fundamentals

Removal of an obstacle: Problem-solving behavior in pigeons.

Nakajima et al. (1993) · Journal of the experimental analysis of behavior 1993
★ The Verdict

Mastering a small part first lets later problem solving look like magic.

✓ Read this if BCBAs teaching chained skills or problem solving to any learner.
✗ Skip if Clinicians who only run discrete-trial drills with no chain steps.

01Research in Context

01

What this study did

Scientists worked with pigeons in a lab cage. A small wooden block sat in front of a key the birds needed to peck.

First the birds got separate lessons. Food appeared only when they pushed the block with their beaks. Later the block was placed in front of the key. Birds that had the pushing lessons quickly slid the block away and pecked the key. Birds without the lessons did not. A month later the trained birds still solved the task.

02

What they found

Learning to push the block first made the birds “see” the answer. Without that history they stared at the setup but never removed the block.

The skill stuck around. After thirty days the same birds cleared the obstacle right away. Reinforcement history, not sudden insight, created the smart move.

03

How this fits with other research

Green et al. (1975) also shaped new pigeon moves. They used food to sculpt a curved peck pattern, showing reinforcement can build long response chains. S et al. extend that idea to problem solving: first shape a simple part, then watch the whole sequence appear.

Vos et al. (2013) found that delaying food drops makes pigeons peck less. That seems to clash with our study, because here the final food comes only after the block is moved—an extra step that could act like a delay. The difference is signaling. In S et al. each push still produced immediate clicks and food once the path was clear, so the contingency stayed intact. P et al. purposely inserted empty seconds that were never paired with food, weakening the link.

Eisenmajer et al. (1998) add that unsignaled 3-s delays wreck performance. Their data remind us to keep each step in the chain clearly tied to its consequence, whether we teach birds or children.

04

Why it matters

Your learner may look stuck, but the missing piece could be a tiny prerequisite skill. Break the task down, reinforce one small move—like pushing a block—and then return to the bigger goal. The pigeon data say the “aha” moment is really just old learning showing up in a new place. Try it with shoe tying, requesting, or any chained task: master one link first, then watch the whole chain fall into place.

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Pick a task your learner struggles with, teach one tiny precursor skill alone, then re-present the full task and see if the block is removed.

02At a glance

Intervention
other
Design
single case other
Sample size
4
Population
neurotypical
Finding
positive

03Original abstract

The importance of a subject's personal history in the solution of an obstruction problem was demonstrated with pigeons. Four birds were trained to peck a key located outside the chamber by poking their heads through an opening in a screen. During tests, a white block was placed in front of the opening, so that it was not possible to peck the key without removing the block. All birds failed to remove the block. However, all birds that were subsequently trained to push the white block around the chamber in the absence of the key and a few of the birds trained similarly but with a black block solved the problem by pushing the block aside and pecking the key. One bird showed the abrupt descent in the learning curve that has been considered a characteristic of "insightful" problem solving. All birds maintained their successful performance after a 1-month interval with no intervening tests.

Journal of the experimental analysis of behavior, 1993 · doi:10.1901/jeab.1993.59-131