Doricchi, F., Willmes, K. & Burr, D. (2019).
Cortex, (114), 1-4.
From our very early school years we start to realize that numbers govern much of our life. A glance at the headlines will tell us a crucial parliamentary bill was defeated by 149 votes, that inflation is steady at .9%, that the GNP has declined by 1% and so on. A flick of our telephone gives us the time (in digits) and date, the telephone numbers of our friends, with apps to furnish our bank balance, and how many steps we have made today. However, these symbolic representations of quantity, usually by Arabic numerals, capture only a small fragment of our daily experience with numerable quantities, and how these quantities guide our behaviour, and the ways we exploit our inner ability to “sense” the numerosity of these quantities. By showing that birds can perform both simultaneous visuo-spatial and temporal-sequential coding of the numerosity of simple visual items (clouds of dots), the German zoologist Otto Koehler (1941; 1950) was among the first to suggest that the symbolic mathematical competence that characterises much human activity might be grounded in phylogenetically older systems that allow approximate, but behaviourally adaptive, estimates of numerosity. During biological evolution these rudimentary mathematical abilities might have been crucial for survival and adaptation by allowing, for example, the recognition and memorization of environments with more or fewer food items, or by favouring rapid “fight or flight” decisions dependent on the relative numerosities of conspecific allies and opponents. Over the past 25 years the study of the neural bases and the functional mechanisms that regulate mathematical cognition in animals and humans has proliferated. In this special issue, we offer an overview of some promising lines of ongoing research on number processing in the brain. The various contributions cover different aspects of mathematical cognition, including studies of the basic neural and functional mechanisms that underlie the sense of numerosity, the interaction between number and the representation of space or time (a field pioneered by Galton's (1880 a,b) description of mental number lines and revitalised by the discovery of the Spatial-Number Association of Response Codes, i.e., the SNARC effect, by Dehaene et al., 1993), the neural regulation of mathematical operations and the correlates of normal or abnormal development of mathematical competence.