ABA Fundamentals

Failure to produce response variability with reinforcement.

Schwartz (1982) · Journal of the experimental analysis of behavior 1982
★ The Verdict

Reinforcement meant to create flexibility can accidentally glue stereotypy in place.

✓ Read this if BCBAs shaping new responses or trying to break repetitive behavior chains.
✗ Skip if Practitioners working only on skill acquisition without stereotypy concerns.

01Research in Context

01

What this study did

Researchers worked with pigeons in a small lab chamber.

The birds had to peck two keys in new four-peck orders to earn food.

Repeating the same order never paid off.

The team wanted to see if the birds would keep inventing fresh patterns.

02

What they found

The pigeons kept using the same few orders again and again.

Even when repetition lost them food, the old patterns stayed strong.

Reinforcement meant to create variety actually locked in stereotypy.

03

How this fits with other research

Schwartz (1980) first showed that plain reinforcement can build rigid pigeon routines.

The 1982 study tried to break that rigidity by paying for novelty, but it failed.

Arantes et al. (2012) later proved pigeons can learn to prefer and protect varied patterns when the payoff setup is clearer.

Together the three papers trace a line: stereotypy is the default, yet variability can be taught with smarter contingencies.

04

Why it matters

Your client may also get stuck in one rigid response even when it no longer pays.

Before you add rewards for novelty, check that the learner truly sees the new rule.

Start with short sets, give clear signals, and reinforce the moment variety shows up.

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Probe whether the learner notices the novelty rule—if not, simplify the contingency and reinforce the first novel response immediately.

02At a glance

Intervention
differential reinforcement
Design
single case other
Population
other
Finding
negative

03Original abstract

Two experiments attempted to train pigeons to produce variable response sequences. In the first, naive pigeons were exposed to a procedure requiring four pecks on each of two keys in any order, with a reinforcer delivered only if a given sequence was different from the preceding one. In the second experiment, the same pigeons were exposed to this procedure after having been trained successfully to alternate between two specific response sequences. In neither case did any pigeon produce more than a few different sequences or obtain more than 50% of the possible reinforcers. Stereotyped sequences developed even though stereotypy was not reinforced. It is suggested that reinforcers have both hedonic and informative properties and that the hedonic properties are responsible for sterotyped repetition of reinforced responses, even when stereotypy is negatively related to reinforcer delivery.

Journal of the experimental analysis of behavior, 1982 · doi:10.1901/jeab.1982.37-171