Underextension Definition | Psychology

In psychology, underextension is when someone uses a category word as if it is applied to only a single thing. It’s often a thing children experience before their language is more developed and their understanding improved.

Imagine your child has a dog, and calls it dog, but doesn’t know what to call all other dogs. They’ll often do this for toys and markers and any other thing that keeps their tiny cutesy little brains involved at a young age. Underextension occurs less and less as children develop their understanding of language.