Ancestor reverence is not the same as the worship of a deity or deities. In some Afro-diasporic cultures, ancestors are seen as being able to intercede on behalf of the living, often as messengers between humans and the gods. As spirits who were once human themselves, they are seen as being better able to understand human needs than would a divine being. In other cultures, the purpose of ancestor veneration is not to ask for favors but to do one's filial duty. Some cultures believe that their ancestors actually need to be provided for by their descendants, and their practices include offerings of food and other provisions. Others do not believe that the ancestors are even aware of what their descendants do for them, but that the expression of filial piety is what is important.
Most cultures who practice ancestor veneration do not call it "ancestor worship". In English, the word worship usually refers to the reverent love and devotion accorded a deity (god) or God. However, in other cultures, this act of worship does not confer any belief that the departed ancestors have become some kind of deity. Rather, the act is a way to respect, honor and look after ancestors in their afterlives as well as seek their guidance for their living descendants. In this regard, many cultures and religions have similar practices. Some may visit the graves of their parents or other ancestors, leave flowers and pray to them in order to honor and remember them, while also asking their ancestors to continue to look after them. However, this would not be considered as worshipping them since the term worship shows no such meaning.
In that sense the phrase ancestor veneration may convey a more accurate sense of what practitioners, such as the Chinese and other Buddhist-influenced and Confucian-influenced societies, as well as the African and European cultures see themselves as doing. This is consistent with the meaning of the word veneration in English, that is great respect or reverence caused by the dignity, wisdom, or dedication of a person.
Although there is no generally accepted theory concerning the origins of ancestor veneration, this social phenomenon appears in some form in all human cultures documented so far. David-Barrett and Carney claim that ancestor veneration might have served a group coordination role during human evolution, and thus it was the mechanism that led to religious representation fostering group cohesion.