Handy numerals: compositional elements in body-based numeration systems

Body-based numeration systems represent numbers through the use of body parts and hence are subject to constraints imposed by human anatomy. Body parts are readily available and can be manipulated in three-dimensional space, but are also predetermined in shape and quantity, which creates both opportunities and obstacles. Strategies to produce composite numerals include the recruitment of compositional elements, such as numeral bases. This article aims to uncover which types of compositional elements (‘compositional anchors’) are present in body-based numeration systems and how they are represented. Analysing the data from the BodyBase database, we find that compositional elements appear in various types and values, showing both similarities with and differences from verbal and notational systems. The representations of main compositional anchors employ various strategies, including different types of movements, hand shapes and physical space. We discuss patterns of compositionality in body-based systems and how they are shaped by format-specific characteristics, and compare the systems of body-based representations with systems in other formats. This article is part of the theme issue ‘A solid base for scaling up: the structure of numeration systems’.