THE DICTATION OF ITALIAN NUMERALS

Some recent studies on acalculia raise the question of how people translate verbal numerals (e.g. three hundred and sixty five) into Arabic numerals (365). This ability can conveniently be tested by a dictation task: The experimenter presents a spoken verbal numeral which the subject must write down in Arabic digits. Two broad categories of dictation error have been observed in acalculia studies. First, the patient may select a wrong digit (“lexical“ error, e.g. 364); secondly, he may produce a numeral with the wrong overall structure, in particular by inserting the wrong number of zeros (“syntactic” error, e.g. 30065). The present study examines another source of evidence, the performance of children who are in the process of acquiring this ability (the crucial age is around 6-8 years). A total of 15 Italian children were given a graded dictation test for numbers below 1 million. In comparison with acalculia patients, the most striking result was the overwhelming preponderance of syntactic errors of 128 errors scored, 111 were classified as syntactic and only 3 as lexical. The most common syntactic error was the insertion of extra zeros (e.g. 30065 or 3065 instead of 365). A formal theory explaining such errors is proposed. According to the theory, the production of an Arabic numeral like 365 requires the combination of 300 and 65 by a string operation which we call “over-writing”; children who have not yet learned this operation tend to fall back on concatenation.