Ancestral religious beliefs of Asabano people in Central New Guinea such as souls, object spirits, sprites, cannibal witches were transmitted every day and in male and female initiations focused on ancestral bones to activate food production. These beliefs changed when missionaries introduced Christianity. I describe the religious beliefs and their causes that prevailed before and after this transition. Interviewees attributed their beliefs to experiences of presences, elders’ claims, supernaturally caused objects and events, and spiritual encounters in dreams and visions. I suggest that such « spirit signs » are explicable and cross-culturally comparable when classified as illusions, trusted testimonies, confirming interpretations, and autonomous imaginings.