Religions permeate the lives of billions of people and are thought to play a vital role in normative behavior. However, we do not know how religious piety penetrates cognitive processes during decision making. The CREDO project therefore proposes to create a computational model of religious decision making. The model works with the assumption that religious faith, formed through religious practice, creates a strong foundation in the mind. When the mind simulates possible actions during decision making, religious actions are easily accessible and selected due to their high value. The CREDO project will develop this computational model which will then be empirically tested with laboratory and field studies to show how religious belief influences the strength of religious priors during normative decision making. In addition, a large-scale cross-cultural study will establish how the beliefs and practices of different religious traditions influence cognitive computations during normative decision making.