Quantity or numerosity is one of the basic properties of our environment. Humans and animals both have the neural representation of quantity or 'number sense'. The ability to extract and to manipulate numbers is closely related to our various cognitive functions such as the capacity of working memory, mathematical achievement, and texture perception. Evidence shows that the sense of number is not a unitary mechanism but rather a composition of two distinct processes; enumeration and estimation. The review examines how numerosity is represented in the visual domain and its relation to different modes of attention. Enumeration or counting permits an exact representation of a distinct number of objects, with an awareness of each object achieved through focal deployment of attention to each object serially. On the other hand, estimation involves an approximation of the number of different items or a sense of ensemble statistics, achieved through fast deployment of distributed attention over a set of objects as a whole. In this overview we suggest that a focused attention mode is more suitable for enumeration, whereas a distributed attention mode is better for estimation. WIREs Cogni Sci 2011 2 634-638 DOI: 10.1002/wcs.136 This article is categorized under: Psychology > Attention.
Copyright © 2010 John Wiley & Sons, Ltd.