Some tests of response membership in acquired equivalence classes.

Researchers tested whether pigeons treat their own key-peck patterns as part of an equivalence class.

Birds first learned to match colors to center-key pecks (short vs long bursts).

Next the team probed for emergent matches between the peck patterns themselves, without colors.

Across three experiments the birds never treated their own peck patterns as equivalent.

Even when the response patterns controlled food, they did not enter the stimulus class.

The authors conclude that responses alone lack the perceptual glue needed for equivalence.

Anonymous (1993) and Rapport et al. (1996) both saw strong equivalence classes in adult humans.

The difference is not a true contradiction: people have language and naming that pigeons lack.

Alonso-Álvarez et al. (2018) later showed that contextual cues, not new relational frames, can explain similar performances, extending the idea that equivalence needs more than shared function.

When you teach conditional discriminations, remember that the learner’s own responses probably won’t become equivalent stimuli unless they are paired with shared names or perceptual features. Pair each response with a clear verbal or visual cue if you want emergent relations to form.