Full Idea
Psychologists often use 'concept' and 'category' interchangeably.
Gist of Idea
Psychologist treat concepts as categories
Source
Edouard Machery (Doing Without Concepts [2009], 1.1)
Book Reference
Machery,Edouard: 'Doing Without Concepts' [OUP 2009], p.8
A Reaction
Well they shouldn't. Some concepts are no more than words, and don't categorise anything. Some things may be categorised by a complex set of concepts.