No. 06
Why Digit Span Differs Between Languages
A study where Chinese speakers had longer spans than English speakers, and another where spans shrank when measured in Welsh. How the spoken length of number words changes memory span.
Digit span is reported as a number of digits, but what you actually rehearse in your head are the digits' names, that is, speech sounds. So the number of digits you can remember depends on the language you think them in.
About two seconds of speech
Baddeley, Thomson and Buchanan (1975) reported the word length effect: lists of short words are remembered better than lists of long words. People generally remembered about as much as they could read aloud in roughly two seconds. The interpretation is that the phonological loop is limited less by the number of items than by the time it takes to rehearse them.
Welsh and English
Ellis and Hennelly (1980) studied children who spoke both Welsh and English. Welsh number words take longer to pronounce than English ones, and the same children had shorter digit spans when tested in Welsh. The researchers used this to explain why digit span scores on the Welsh version of an intelligence test came out lower: the difference lay not in intelligence but in the length of the number words.
Chinese and English
Stigler, Lee and Stevenson (1986) compared digit memory in Chinese and English speakers. Chinese number words are all single syllables and are pronounced quickly, and Chinese speakers had longer digit spans. The researchers saw this as evidence for a memory store limited by time.
Comparing several languages
Naveh-Benjamin and Ayres (1986) compared speakers of English, Spanish, Hebrew and Arabic and reported that languages whose number words can be read faster tended to show longer digit spans.
| Language | Number words (1–5) | Notes |
|---|---|---|
| --- | --- | --- |
| Korean (Sino-Korean) | 일, 이, 삼, 사, 오 (il, i, sam, sa, o) | All one syllable |
| Chinese | yī, èr, sān, sì, wǔ | All one syllable |
| Japanese | いち, に, さん, し/よん, ご (ichi, ni, san, shi/yon, go) | 1–2 syllables; some digits have two readings |
| English | one, two, three, four, five | Mostly one syllable; seven and zero have two |
| Spanish | uno, dos, tres, cuatro, cinco | A mix of two-syllable words |
The syllable counts in this table are only a rough clue to spoken length; they are not research figures comparing digit spans across languages.
What this means on this site
- Comparing your score with someone who speaks a different language means little. The same memory can score higher when tested in a language with shorter number words.
- If you're bilingual, your score may depend on which language you silently rehearse in. Use the same language when comparing your results.
- Listening mode reads the digits with a voice in the current page language. Speech synthesizers speak at different rates, so even in the same language the difficulty may feel slightly different from device to device.
Sources: Baddeley, Thomson & Buchanan (1975) Journal of Verbal Learning and Verbal Behavior 14(6):575–589 · Ellis & Hennelly (1980) British Journal of Psychology 71(1):43–51 · Stigler, Lee & Stevenson (1986) Cognition 23(1):1–20 · Naveh-Benjamin & Ayres (1986) Quarterly Journal of Experimental Psychology 38A(4):739–751