On the difficulty of relational concepts among participants with Down syndrome.

Facon et al. (2012) asked whether Down syndrome makes relational concepts extra hard. They tested three matched groups: kids with Down syndrome, kids with other intellectual disabilities, and typically developing peers. All children saw the same set of relational tasks—things like bigger-smaller, same-different, before-after. The team then ranked the tasks from easiest to hardest for each group.

The goal was simple: see if the disorder changes the learning order. If Down syndrome created special trouble, the ranking should look different from the other two groups.

The rank order came out almost identical across groups. Once overall ability was leveled, sequence—not diagnosis—predicted difficulty. A task that sat in the middle of the list for typical kids sat in the middle for both disability groups as well.

In plain words, Down syndrome did not add extra relational baggage. The concept itself, not the label, set the challenge.

Emmelkamp et al. (1986) once showed that kids without language rarely form stimulus equivalence classes. That finding seems to clash with Bruno’s “no-difference” claim. The gap closes when you notice M required language as a gate; Bruno matched ability first and then looked at order. Language skill still matters for initial class formation, but it does not re-order which relations are tougher once kids are equated.

Cox et al. (2015) extended the same matched-ability trick to autism. They also found that relational reasoning difficulty lines up with overall developmental level, not the autism label. Together the three studies build a rule: control ability and diagnostic differences in relational tasks fade.

Gomes et al. (2023) went a step further and actually trained adults to link separate equivalence networks. Their positive results show relational responding is teachable across the lifespan, backing Bruno’s view that the concepts themselves—not the syndrome—set the pace.

Stop blaming Down syndrome for every relational stumble. First check the child’s global ability, then pick concepts in the natural difficulty order: start with simple same-difference, move to bigger-smaller, save before-after for last. This sequence works for any kid at that ability band, so one lesson plan now fits many labels.