How does the finding of grave goods in ancient graves equate to the forming of a social hierarchy?

Grave goods, in archaeology and anthropology, are the items buried along with the body.

They are usually personal possessions, supplies to smooth the deceased's journey into the afterlife or offerings to the gods. Grave goods may be classed as a type of votive deposit. Most grave goods recovered by archaeologists consist of inorganic objects such as pottery and stone and metal tools but organic objects that have since decayed were also placed in ancient tombs. Funerary art is a broad term but generally means artworks made specifically to decorate a burial place, such as miniature models of possessions including slaves or servants for "use" in the afterlife.