A question that may be asked about an adaptation is whether it is generally obligate (relatively robust in the face of typical environmental variation) or facultative (sensitive to typical environmental variation).  The sweet taste of sugar and the pain of hitting one's knee against concrete are the result of fairly obligate psychological adaptations; typical environmental variability during development does not much affect their operation. By contrast, facultative adaptations are somewhat like "if-then" statements. For example, adult attachment style seems particularly sensitive to early childhood experiences. As adults, the propensity to develop close, trusting bonds with others is dependent on whether early childhood caregivers could be trusted to provide reliable assistance and attention. The adaptation for skin to tan is conditional to exposure to sunlight; this is an example of another facultative adaptation. When a psychological adaptation is facultative, evolutionary psychologists concern themselves with how developmental and environmental inputs influence the expression of the adaptation.
One of the attributes of our intuitive psychology of mind is that humans are interested in the affairs of other humans. This may result in the tendency for concepts of supernatural agents to inevitably cross connect with human intuitive moral feelings (evolutionary behavioral guidelines). In addition, the presence of dead bodies creates an uncomfortable cognitive state in which dreams and other mental modules (person identification and behavior prediction) continue to run decoupled from reality producing incompatible intuitions that the dead are somehow still around. When this is coupled with the human predisposition to see misfortune as a social event (as someone's responsibility rather than the outcome of mechanical processes) it may activate the intuitive "willingness to make exchanges" module of the human theory of minds resulting in the tendency of humans to try to interact and bargain with their supernatural agents ( ritual ).