If you have ever asked a stranger for directions, especially in a place where people speak in a wonderful Scottish accent, you may relate to the experience of the driver in this video:

It may not be such a challenge to remember directions if your memory span—that is, the number of items you can recall in correct order immediately upon presentation—was larger, or if you completely understand the title of this post, “As easy as Yī-Èr-Sān.”

A well-replicated result is that if your native language is a Chinese language, then your memory span is bigger than if your native language were English. At least this is the case with digit span. Digit span is assessed with the aptly named digit span test in which a string of digits is presented for immediate ordered recall.

Why do native Chinese language speakers fare better? The dominant explanation is that they are faster at rehearsing, which then allows them to repeat more digits before they are forgotten. Rehearsing in this sense is repeating material in your own head (known as “subvocal articulation”).

A recent article in the Psychonomic Society’s journal Memory & Cognition tested this explanation.

To test the hypothesis that differences in span between native English and Mandarin speakers are due to faster articulation speed, researchers Sven Mattys, Alan Baddeley, and Danijela Trenkic tested native speakers of both languages on a digit-span task and measured the rate of articulation. To rule out the alternative explanation that the effect is due to greater experience with digits of the Chinese students over English students—rather than the speed of rehearsal— the researchers tested participants on a word span task too.

In the experiment, the native Mandarin speaking participants were presented with strings of digits and then strings of words. After each string, participants tried to repeat the items in the same order. The strings started with three items and increased in length until participants could no longer accurately repeat the string. The stimuli were first presented and repeated in Mandarin and then presented and repeated in English.

The procedure was the same for native English speaking participants, except there were no Mandarin items. Importantly, the digits and words did not differ in their presentation durations. The figure below shows an example of the method.

You can try this yourself using the videos below.

For Mandarin speakers (or for English speakers wishing to challenge themselves):

For English speakers:

(Thanks to the authors for providing the stimuli for this example.)

What did Mattys and colleagues find?

First, native Mandarin speakers outperformed native English speakers on tests of digit span when the digits were presented in their native language. This result is shown in the figure below. This replicates previous findings. The results also show that the span was smallest when the digits were presented in their non-native language.

Second, the superior digit span of native Mandarin speakers extended to words that were presented in their native language, as shown in the figure below. These results rule out the explanation that Chinese participants have a larger digit span because of their greater exposure to digits during their education than English participants. And as with digits, the span was smallest when the words were presented in the non-native language.

Third, Mandarin speakers produced more syllables per second than English speakers when the stimuli (both digits and words) were presented in their native language. This is shown in the figures below. When the digits or words were presented in their non-native language, participants produced fewer syllables per second than when the digits or words were presented in their native language.

To delve further into the favoured explanation that rehearsal rates account for the superior performance of the Mandarin speakers on Mandarin stimuli, Mattys and colleagues conducted correlational analyses on an individual participant level. That is, articulation rate and memory span was obtained for each participant, and the correlation between those two measures across participants was computed.

The figure below shows that high memory span was strongly related to a faster rate of articulation, although that correlation was attenuated for the Mandarin speakers. These results cast doubt on the theory that faster rehearsal fully accounts for the superior performance of the Mandarin speakers when tested in their native language.

Mattys and colleagues concluded that rehearsal by articulating does aid memory span, but that something else does too. They suggested that “refreshing” is another type of rehearsal that may also play a role. Refreshing is attending to the memory representation of an item while in short term storage. According to the authors, “It is possible that Chinese speakers have learned to use both articulation and refreshing simultaneously”.

It appears, from these results, that the difference in performance is partially due to an enhanced storage capacity. This likely reflects cultural differences. For example, the use of rote memory is more prevalent in Chinese culture. Learning thousands of characters in Mandarin versus learning 26 characters in English might give the edge to the Mandarin speakers. Whatever the reason, the effect is particularly strong and gives us a glimpse into the workings of working memory.

Psychonomics article focused on in this post:

Mattys, S. L., Baddeley, A., & Trenkic, D. (2018). Is the superior verbal memory span of Mandarin speakers due to faster rehearsal?  Memory & Cognition, 46, 361-369. https://doi.org/10.3758/s13421-017-0770-8.