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Cultural Effects on the Mental Number Line

This special issue is the result of a workshop on the cultural effects on the mental number line held in York (U.K.) in July 2009. The workshop was funded by the Experimental Psychology Society (www.eps.ac.uk) and the European Society for Cognitive Psychology (www.escop.eu), and we thank both organisations for sponsoring the event. The aims of the workshop were to bring together experimental psychologists who study effects of cultural variables on numerical cognition, to facilitate insights into the development and flexibility of numerical cognition by comparing across cultures, and to provide an up-to-date cross-disciplinary overview of research into cultural aspects of numerical cognition that encompasses behavioural, observational, Internet-based, and neuroscientific methods. This special issue gives a lively and accurate representation of the breadth and depth of the workshop contributions. Humans are intrinsically driven to represent numerosity in many ways. The “mental number line” in our title is a metaphor for number representations that are not linguistically mediated but spatial in nature. The most common spatial representation of numbers in Western societies is a left-to-right arrangement for numbers of increasing magnitude (such as on rulers). While this is not the only spatial representation of numbers (think of thermometers, hands, clocks, ...), it seems to have a profound effect on our numerical cognition. This has led to the discovery of the SNARC effect and to the relative neglect of other spatial mappings. Several articles in this special issue illustrate the variety of interactions that emerge between number representations and cultural preferences over the time course of our enculturation (see Figure 1). Finger counting, for example, is ontogenetically one of the first methods used to represent numerosity. Lindemann, Alipour, and Fischer show cultural differences in finger counting that persist well into adulthood. The question about what causes those differences is at the heart of this special issue. Evidence for two potential causes is presented: Cultural differences might be driven by the direction of reading or by differences in the existence, structure, or use of number words. Bender and Beller investigate the variability in linguistic structures used in Polynesian and Micronesian languages by documenting the development of those numeration systems and suggest how this development might have influenced spatial representations. Data by Helmreich et al. juxtaposing Germanand Italianspeaking children show that the structure of the numeration system used in a particular language can indeed influence the accuracy of spatial-numerical mappings. And it does not only affect spatial representations: Krinzinger et al., comparing children speaking French, German, or Flemish, show clearly that the consistency of the numeration system has an effect on children’s ease of acquisition of number words and number transcoding. Furthermore, Butterworth et al. show that in a culture that has no number words children use spatial strategies very effectively to solve numerical tasks. They investigated number processing in aboriginal children in Australia and also report the curious lack of finger counting in this population.