Full Idea
A concept's content influences how easy it is to learn. If the concept is grossly incompatible with what people know prior to the experiment, it will be difficult to acquire.
Gist of Idea
Concepts with familiar contents are easier to learn
Source
Gregory L. Murphy (The Big Book of Concepts [2004], Ch. 6)
Book Reference
Murphy,Gregory L.: 'The Big Book of Concepts' [MIT 2004], p.148
A Reaction
This is a preliminary fact which leads towards the 'knowledge' theory of concepts (aka 'theory theory'). The point being that the knowledge involved is integral to the concept. Fits my preferred mental files approach.