As a defining aspect of what it means to be human, culture is a central concept in anthropology, encompassing the range of phenomena that are transmitted through social learning in human societies. The word is used in a general sense as the evolved ability to categorize and represent experiences with symbols and to act imaginatively and creatively. This ability arose with the evolution of behavioral modernity in humans around 50,000 years ago.[citation needed] This capacity is often thought to be unique to humans, although some other species have demonstrated similar, though much less complex abilities for social learning. It is also used to denote the complex networks of practices and accumulated knowledge and ideas that is transmitted through social interaction and exist in specific human groups, or cultures, using the plural form. Some aspects of human behavior, such as language, social practices such as kinship, gender and marriage, expressive forms such as art, music, dance, ritual, religion, and technologies such as cooking, shelter, clothing are said to be cultural universals, found in all human societies. The concept material culture covers the physical expressions of culture, such as technology, architecture and art, whereas the immaterial aspects of culture such as principles of social organization (including, practices of political organization and social institutions), mythology, philosophy, literature (both written and oral), and science make up the intangible cultural heritage of a society.