The African devotion to his/her ancestors has been taken as the singular characteristic of African spiritual awareness, and so some early writers on African indigenous Culture referred to African Traditional Religion as ancestor worship. That is, African spirituality in essence is the worship of dead and gone great, great grand-parents.
Some early missionary writers on African traditional religion also confused African ancestors with spirits, and as a belief in spirit was considered superstitious, the veneration of the ancestors was seen as the cult of the spirits i.e. a form of animism.
Since Africans are said to be afraid of evil spirits (ancestors) it was concluded that therefore they have instituted the cult of the ancestors so as to placate them through sacrifices and thus avoid any harm from them. The dead are therefore likened to malevolent spirits and so these early writers on African Traditional Religion concluded that fear of spirits (ancestors) appears to lie at the root of the ancestor cult. That means they agreed with Henry Bergson, the French Philosopher, that fear first begat the gods.
This is an unfortunate misrepresentation of the ancestor ritual and if the conclusion is valid then it means that Christianity, Islam etc. are equally founded on fear of evil spirits.
An ancestor in Africa:
The English word ancestor (meaning one from whom one is descended and who is usually more remote in the line of descent than a grandparent) is used to describe an African social phenomenon and to translate African Concepts which are not quite similar in meaning as the English term. I shall use Ewe and Akan terms for ancestor to illustrate my point. The Ewe and Akan terms for ancestor as used in the ancestor veneration are: Ewe: mama/togbui (sing.), mamawo/togbuiwo (plur.), Twi: nana (sing.) nananom (plur.). These terms are used for the living ancestors elders respectively. The same terms are used in Ewe for the dead ancestors. In Twi the word asaman is added to the singular nana and nsamanfo to the plural to form nana asaman and nananom nsamanfo as the singular and plural nouns for the dead ancestor(s). see the accompanying diagram: Defining names for ancestor in Ewe and Twi.