Ritual explained: interdisciplinary answers to Tinbergen's four questions.

Convergent developments across social scientific disciplines provide evidence that rituals are a psychologically prepared and culturally inherited behavioural hallmark of our species. The dramatic diversity of ritual practices ranges from simple greetings to elaborate religious ceremonies, from the benign to life-threatening. Yet our scientific understanding of this core human trait remains limited. Explaining the universality, functionality and diversity of ritual requires insight from multiple disciplines. This special issue integrates research from anthropology, archaeology, biology, primatology, cognitive science, psychology, religious studies and demography to build an interdisciplinary account of ritual. The objective is to contribute to an integrative explanation of ritual by addressing Tinbergen's four key questions. These include answering ultimate questions about the (i) phylogeny and (ii) adaptive functions of ritual; and proximate questions about the (iii) mechanisms and (iv) ontogeny of ritual. The intersection of these four complementary lines of inquiry yields new avenues for theory and research into this fundamental aspect of the human condition, and in so doing, into the coevolution of cognition and culture. This article is part of the theme issue 'Ritual renaissance: new insights into the most human of behaviours'.