Language effects in addition: How you say it counts

Abstract

This study aimed to investigate the role of language in calculation. Two populations were compared, one with a base-10 language, and another (Basque) in which number words are constructed by combining multiples of 20 and units or teens (e.g., “35” is said “twenty and fifteen”). Experiment 1 asked participants to verbally solve additions presented as Arabic digits. Basque participants solved the additions that consisted of a multiple of 20 and a teen (e.g., 20 + 15) faster than controls with identical answers (e.g., 25 + 10). No differences were found in the base-10 language group. Experiment 2 replicated this result even if participants had to type the answer on a numerical keypad, instead of saying it. Hence, the structure of number words in each of the languages influenced the way additions were solved, even if language was not necessary for conducting the task. Finally, in Experiment 3, both language groups performed a numerical comparison task in which no effects of the structure of number words were obtained. Results of the three experiments are discussed in light of current models of numerical cognition.

Keywords:

• Language
• Addition
• Number comparison
• Numerical cognition

Acknowledgments

This research was supported by a Research Training Network fellowship from the European Commission (HPRN–CT–2000–00076) as well as by the programme Consolider Ingenio 2010 (CSD2007–00012) and a grant (SEJ 2007–60751) from the Spanish Government. Support for the research of N.S-G. was received through the prize “ICREA Academia” for excellence in research, funded by the Generalitat de Catalunya. The authors are very grateful to Eider Gutierrez, Kepa Erdozia, and Oxel Uribe-Etxebarria for their help with testing the Basque participants. In addition, many thanks to Mikel Santesteban, Luisa Girelli, Alessia Granà, and Carlo Semenza for participating in interesting discussions regarding this research. Finally, we remain indebted to Xavier Seron and Marie-Pascale Noël for their helpful comments on a previous version of this manuscript. Part of the research reported here was conducted while the first author was a postdoc at the Università degli Studi di Trieste (Italy).

Notes

¹ Through all the paper the word “format” is used to refer to the external representation of numbers and “code” to talk about their internal representation.

² In German, no main effect of compatibility was found, but there was a significant interaction of Compatibility × Unit Distance. In English, no effects of compatibility at all were obtained.

³ Zhou, Chen, Chen, and Dong (2008) showed that finding a compatibility effect might depend on how numbers are displayed: Simultaneous presentation led to compatibility effects, while sequential presentation favoured a holistic comparison. We opted for avoiding sequential displaying because it requires keeping the first number in working memory. If the phonological loop is engaged in this process, language effects might be found. However, we were not interested in representations in short-term memory processing, but on the code of long-term representations. To avoid any confounding in the location of hypothetical language effects, we discarded this type of presentation.