Equivalence class formation in language-able and language-disabled children.

The team worked with two groups of preschoolers. One group could talk or sign. The other group had little or no working speech or signs.

Each child learned to match pictures and objects in three steps. After training, the testers checked if the kids picked new, untrained matches. This final test shows whether the child has built an equivalence class.

Every child who could use words or signs passed the final test. None of the language-disabled children passed.

The authors say a child needs some working language before equivalence classes can form.

Ayres-Pereira et al. (2018) later showed that typical preschoolers do form classes, but some fail to transfer the relation from photos to real objects. Their work extends the 1986 finding by adding a 2-D to 3-D generalization probe.

Baer et al. (1984) worked with language-disabled preschoolers two years earlier. They taught yes/no replying inside real requests and saw fast success. Their paper foreshadows the 1986 warning: build basic communication first, then run higher-order tasks.

Fields et al. (1991) pushed the topic further. After adults formed classes, they generalized to new line lengths that looked like trained members. The 1991 study keeps the equivalence idea but drops the language focus, showing the effect holds once language is present.

Before you start equivalence-based reading or math programs, check if the learner can ask, name, or sign. If not, teach core communication first. A quick test: have the child request five favorite items. Success means equivalence training may work. Failure means pause and build language or sign skills.