Gestalt principles make clear how to distribute elements on the page, when and why to use line delineation, background shading, a gradient, or when and why to group things in an enclosure (or not).
Human perception is governed by relationships; how things are similar or dissimilar, how they contrast or blend with one another, and how arrangements of things suggest hierarchies and are affected by context.
Elements are perceived as either figures (distinct elements of focus) or ground (the background or landscape on which the figures rest).
Determining the figure ground relationship is also the very first thing people do when they direct their gaze
Our perception of the figure ground relationship allows us to organize what we see by how each object relates to others. The short and sweet version is: it allows us to determine what we’re supposed to look at and what we might safely ignore.
when we are made to look at something unfamiliar, especially if it is a designed page, figure ground relationship clues determine the success of our experience.
These relationships are determined both by contrast and by common conventions of human experience …and by other things, as well.