Avoid ambiguous information displays, and test your design to verify that all users interpret the display in the same way. Where ambiguity is unavoidable, either rely on standards or conventions to resolve it, or “prime” users to resolve the ambiguity in the intended way.

Too much text in a user interface loses poor readers, who unfortunately are a significant percentage of the population. Too much text even alienates good readers: it turns using an interactive system into an intimidating amount of work

The idea of the present book is to unite design rules with the supporting cognitive and perceptual science that is at their core.

the principle of Continuity, states that our visual perception is biased to perceive continuous forms rather than disconnected segments.

Providing that rationale and background education is the focus of this book.

Symmetry. It states that we tend to parse complex scenes in a way that reduces the complexity.

when information is presented in a terse, structured way, it is easier for people to scan and understand.

Usability testing is useful, necessary, and inefficient.

all of the design rules are based on human psychology: how people perceive, learn, reason, remember, and convert intentions into action.