“Although it is best when people have considerable knowledge and experience using a particular product—knowledge in the head—the designer can put sufficient cues into the design—knowledge in the world—that good performance results even in the absence of previous knowledge (Norman 76-77).”

Knowledge in the head is the knowledge that the user has from previous experiences, while knowledge in the world is an environmental cue made by the designer to help the user use their design.

These are four types of knowledge according to Norman, head knowledge, world knowledge, how knowledge, and of knowledge. Memory is used in head and of knowledge, while how knowledge is behavioral and world knowledge is environmental. Of knowledge can also be world knowledge because it can be easily written and shared. This is important for designers to consider because head knowledge is usually an experience a user comes in with, so it won’t be taught quickly. Of knowledge can be written in the form of instructions, so it can be given to the user quickly. How knowledge comes only through practice with your design but you can design it in a way that gives hints and world knowledge.

This was shown in my test because users came in with a certain amount of head knowledge and knew enough to be able to use the world knowledge supplied by the library to work the system.