This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.Nigeria is constitutionally a secular country but its citizens are rated among the most religious in the world by several surveys. Religious symbolism is conspicuous in Nigeria, littered from educational institutions to work environments and market places. Semiotics and semantics have a rich history of the study of symbols, however, symbols are also utilized as primes in psychology. Research in social and cognitive psychology suggest that symbols, particularly when embedded with emotive meaning, serve to reinforce particular associated and learnt constructs. The present thesis assesses how religious vs. secular symbols interact with specific cognitive processes and mechanisms (Type I and Type II cognitive processes, agency detection, need for cognitive closure, and immortality bias). Five studies were carried out in Nigeria. Study One showed a high rate of God references in two non-religious Nigerian national newspapers (broadsheet and tabloid). The hypotheses of Studies Two to Five were tested across religious vs. secular situational influences. Studies Two and Three tested hypotheses related to the rationality vs. religion debate through the default interventionist dual process theory. Study Four assessed how Nigerian children (aged 5 to 11 years old) conceive of retrograde immortality through reasoning by analogy about future immortality. Study Five A replicated the previously-reported correlation between need for cognitive closure and religious fundamentalism. Study Five B showed that when uncertainty is primed in individuals the detection of supernatural agency positively mediates, and the detection of human agency negatively mediates, the relationship between need for cognitive closure and religious fundamentalism. Aspects of dual processes theories and the Cognitive Science of Religion (CSR) that are concerned with implicit cognitive functions directly informed this series of experiments, however conformity and self-theories offer complementary explicit/social perspectives. Two sets of recommendations are offered; the first addresses future research in psychology, such as the separation of content from process in the rationality vs. religion debate. The second addresses policy recommendations at three interconnected levels (macro, institutional, and individual)
