Two experiments where we systematically investigated the correspondence between auditory number words and visual Arabic digits in adults. Auditory number words and visual Arabic digits were presented concurrently or sequentially and participants had to indicate whether they described the same quantity. We also investigated whether individual differences in the efficiency of the cross-modal processing were related to differences in mathematical performance.Numeracy is the Cinderella of literacy, much less researched but at least as important for employment and life success as literacy. This research project will investigate the development of a fundamental principle of numeracy, the link between number words and number symbols, with the aim to identify potential risk factors for low numeracy. Children entering primary school need to shift from using mainly spoken numbers words (e.g., 'twenty-three') to being able to write down the correct multi-digit Arabic strings (e.g., '23') upon hearing spoken number words. This is called number word transcoding and fundamental for mathematical development. This project will investigate three aspects of transcoding between number words and Arabic digits. First, we will analyse the mapping between single Arabic digits (e.g., '8') and the corresponding number words (e.g., 'eight'), because the single Arabic digits are the basic building blocks for all Arabic multi-digit strings (e.g. 28732). Most children in primary school already know the single Arabic digits. We propose that the efficiency with which children map between digits and number words is still increasing in primary school. In this project we will test this by measuring the efficiency of the mapping in children of different ages. We will also measure children's mathematical ability to see whether the efficiency of the mapping is related to their mathematical ability. Secondly, this project will investigate multi-digit number transcoding. This is important because most of the numbers children are dealing with in primary school are multi-digit numbers (e.g., 2015) and instructions are often given verbally (e.g., 'thirty-two'). We will follow children from Year 1 to Year 3 and measure their ability to transcode multi-digit numbers as well as other number skills every year. We will also test their maths performance. This study will enable us to decide whether a child's ability to transcode multi-digits accurately in Year 1 predicts how their mathematical ability will develop over the next few years better than other measures of numerical skills. Thirdly, number words depend on the language a person speaks. Non-native children entering primary school will be much less familiar with native number words and their mapping to the Arabic digits. Given the multilingual context of many children in primary school in the UK and across Europe, it is important to find out whether and if so, how, language factors influence the association between spoken number words and Arabic digits. We will investigate the influence of language on number transcoding by comparing monolingual children from two language backgrounds: English and German. In addition to increasing our knowledge about the process of number transcoding, this research project will lead to new ways of assessing children's number skills and will in the long run help native and non-native children who struggle with maths.

Two experiments, stimuli presentation and data recording controlled by Presentation, Version 17.2 (Exp.1) and MATLAB with Psychophysics Toolbox extensions (Exp.2). For experiment 1, individual math performance was assessed with the Math Computation subtest of the Wide Range Achievement Test (WRAT-4, Wilkinson & Robertson, 2006) after the computerised task. Participants were asked to solve as many arithmetic questions as possible in 15 minutes (a maximum of 40 questions). See the methods document for more information.