Human interface guidelines (HIG) are software development documents which offer application developers a set of recommendations. Their aim is to improve the experience for the users by making application interfaces more intuitive, learnable, and consistent. Most guides limit themselves to defining a common look and feel for applications in a particular desktop or mobile environment.
Articles to read
The HIG is… detailed. You’re not going to read through it all in one go. Please start with the below links in preparation for next class.