Hierarchical classification as relational framing.

Lovell et al. (2014) taught adults to sort pictures into groups using two made-up shapes.

One shape meant "this is a member of that group." The other meant "this group includes that item."

After training, the adults could build new groups and place items inside them without further help.

The participants quickly learned to treat the shapes as cues for "member of" and "includes" relations.

Their choices matched the rules seen in child development studies, showing true hierarchical framing.

Hartmann et al. (1982) also used arbitrary cues to give pigeons symbolic "reports." Both studies show that simple cues can stand for complex relations, but Brian’s work extends the idea to human language-like framing.

Castañe et al. (1993) asked whether recall is intraverbal or a tact to private events. Brian’s cue method gives you a way to test the same question with clear contextual cues, tightening control over what is truly verbal.

Nelson et al. (1978) showed that just hearing a word nudges adults to use it later. Brian adds a second layer: cues can control the type of relation (up vs down), not just the words spoken.

You can copy the shape-cue trick in your clinic. Pick two icons: one for "is a kind of," one for "has these parts." Teach them like Brian did, then use them to build categories with your learner. The cues give you a fast, visible way to track hierarchical language as it grows.