When would you include more background in a photograph of a person?

If you wanted to create a blurred background effect when taking a portrait, then it is a good idea to include more back ground in your picture. 

It does not have a picture if you can add that let me know.

Relief sculpture - images are set against a flat background. a coin is a good example: the inscription, the date, and the figure are slightly raised above a flat surface. the ancient egyptians sometimes carved figures into a flat surface.    pro: they take significantly less time to make and do not require as much tools or skills as free-standingcons: not nearly as realistic, as it is not fully 3-d, and does not have the details that a free-standing one does.freestanding sculptures (also called  carved in the round) are not attached to any  background.  they are 3-dimensional  and fully rendered.