Establishing Hierarchical Classification Responding: Directly Trained and Emergent Responses

Noell et al. (2026) taught preschoolers to sort pictures into nested groups. They used short discrete-trial lessons. Kids learned that one picture belonged to both a big group and a small group. For example, a golden retriever is a dog and also an animal.

The trainers first named the pictures. Then they asked kids to pick items by class. They never taught the kids to name the classes aloud. They wanted to see if naming would pop out on its own.

After only a few lessons, every child could pick items by big or small class. They also started naming the classes without being asked. When shown new pictures, they used the right class names. They even answered new questions like 'Which one is NOT an animal?'

Some kids showed class inclusion right away. Others needed one quick prompt. Once they got it, the skill stuck.

Paliliunas et al. (2022) got the same result with children with autism. They used a fun 'I Spy' game instead of table-top trials. Both studies show brief hierarchical training works across kids.

Ming et al. (2018) came first. They taught class inclusion with RFT drills. Noell adds two new pieces: kids also named classes and used the names with brand-new items. It is a step up, not a do-over.

Oliver et al. (2002) showed that teaching one tact to many shapes makes toddlers form new groups. Noell uses the same idea but moves it up to nested groups. The chain is toddler tact → simple class → nested class.

You can build higher-order thinking in minutes. Teach a child that one item fits two labels. Check if they start naming both labels on their own. If they do not, give one quick prompt. Once the child has it, try new items and new questions. This tiny drill can boost vocabulary, sorting, and early science skills without extra teaching time.