How we change what others think, feel, believe and do
When we look at something we separate out a foreground, or figure, and a background, or ground. The foreground is usually the main subject on which we will subsequently focus, whilst the background is generally ignored.
Areas which stand out are more likely to be seen as the foreground figure. This includes those where:
Areas which recede are more likely to be background,
In the picture below, the red rectangle seems likely to be the foreground because:
Note that if there was an extra red area around the outside of the blue, it may be argued that the figure is a blue card with a hole in it.
In making sense of what we see, we look for objects that we can distinguish and name, and so interact with them. To do this, we start out looking for a complete boundary that surrounds the shape. Yet having done so only divides the image into two parts - the surrounded item and the rest of the image. We then have to decide which is the object (or figure) where we should place most attention.
Often, choosing the figure is easy, yet this is not always so. Changing the selection of foreground 'figure' and background 'ground' changes what you see. In the picture below, if the figures is white, then you see a vase. But if the figure is black then you see two heads facing one another. A number of optical illusions are based on this illusion. where figure and ground 'flip' back and forth.
A complication is that any scene may contain many figures and multiple grounds. Attention will first go to the primary figure which stands out the most (larger, brighter, etc.).
The size of an item affects whether it is seen as figure or ground. In many cases, the smaller item will become the figure. In the images below, A appears as a black cross on a white background whilst B may well seem to be a white cross on a black background.
Figures can become grounds when there are objects within the figures. For example if there is a building in a field, the building may well be the figure for attention. Yet if there is a notice on the building, the notice could then become the figure, demoting the building to be the ground.
When a figure is identified, if there are similar shapes nearby, these also will be seen as figures. This property is known as 'surroundness'. This happens because identifying the figure necessarily includes identifying the ground. The ground then throws any other shapes as figures into the foreground. In the diagram below, when A is idenfiied as a figure, E becomes the ground. B, C and D consequently appear as figures (being similar in some way to A helps this).
This principle may also be applied to other senses. For example, when a sound stands out against background 'noise', then it is effectively the 'figure'.
When creating visual images for display, ensure it is easy for viewers to distinguish the figure where you want them to pay attention. Make the figure clear and distinct, standing out from the background.