Bert has a pet at home named Bingo. Bingo has four legs and a tail that wags. Bingo says, "Woof!" Bingo is a dog.

One day, Bert sees a woman holding a cat. Bert points and says, "Dog! Dog!"

The woman says, "This is my cat, Coco. Would you like to pet her?"

Bert pets the cat. He can tell its fur is softer than Bingo's fur. He can hear the cat purr.

Bert now realizes that some four-legged furry animals are dogs and some are cats.

Can you use Piagetian terms to explain this example?