Norman Chapter 1 Psychopathology Jeff Offutt https://www.cs.gmu.edu/~offutt/ SWE 205 Software Usability and Design

Psychopathology Huh ? Anybody know what that means? the study of mental illness or mental distress the manifestation of behaviors and experiences that may be indicative of mental illness or psychological impairment 12-Apr-19 © Jeff Offutt

Basic Concepts Well designed objects are simple to interpret and understand They match our expectations Visibility : The correct parts to any object must be visible and must convey the correct message Mapping : How what you want to do maps to what you can do Affordance : The properties of a thing—especially the fundamental properties that determine how it can be used A chair is for sitting, a classroom is for sleeping 12-Apr-19 © Jeff Offutt

A UI that requires a user manual has already failed Basic Concepts (2) Correlation : Two things happen at the same time Causality : One thing causes the other Humans naturally mix these No, cold weather does not give us colds ! Conceptual model : A mental simulation of how something works A UI that requires a user manual has already failed 12-Apr-19 © Jeff Offutt

Basic Concepts (3) Mental model : How the user expects something to behave If the UI does not match the mental model … fail Natural mapping : Using physical analogies and cultural standards to map the UI to the implementation Feedback : Telling the user that something happened, and what 12-Apr-19 © Jeff Offutt

Why is Designing UIs Hard ? Good UIs take time to design Many programmers are lazy Designing a good UI requires thinking like the user instead of an engineer Engineers often think they are users Different users want different things Engineers love features They want to do everything the technology allows! 12-Apr-19 © Jeff Offutt