Final answer:
The separate object seen is called the foreground, and it stands out from the background. The foreground contains objects that are largest and most detailed due to their proximity to the viewer, while the background is comprised of objects that appear smaller and less detailed.
Step-by-step explanation:
When we see a separate object, it is usually seen as a foreground that stands out from its background, which is called the background. The foreground appears to be nearer to the viewer, with objects that appear largest, darkest, and most detailed. In contrast, the background appears farthest from the viewer with objects that are smallest, least intense, and least detailed. An example of this is how humans with color vision see an apple on a tree; the bright red color of the apple stands out clearly from the green background of leaves. The concept of figure-ground relationship explains visual perception phenomena, such as the classic image which can be perceived either as a vase or as a pair of faces, demonstrating how our perception can shift depending what is identified as figure (foreground) and what as ground (background).