Americans have a longer digit span but a shorter spatial span than Finns

Cross-national studies of test norms show American superiority in digit span (DS) length as compared to European norms. In our study, American and Finnish DS and Spatial span (SS) norms were analyzed to study the hypothesis that the differences in DS reflect a systemic difference in working memory and are not based on linguistic factors.

The mean DS and SS scores from the Wechsler Memory Scale III US (n = 1,250) and Finnish (n = 251) standardizations were compared.

A significant difference between American and Finnish mean DS (16.5-14.2) and SS (14.7-15.9) raw scores was observed. For six out of seven age groups, the American sample had longer DS while for 4/7 age groups, the Finnish sample had longer SS.

It is concluded that differences in DS are based on other factors than a systemic difference in working memory. Cross-national differences in articulatory duration of digit names is probably one major causative factor. The results underline the need for establishing national test norms for memory tests.