If you’re going abroad this summer, flexing your second language skills could do more than help you get by. According to new research in the Journal of Experimental Psychology: General, it may also improve the accuracy of your memories of your trip.

Leigh H. Grant at the University of Chicago and colleagues studied native Mandarin Chinese speakers who also knew English. Across two experiments, they found that when the participants used English, their foreign language, they were less susceptible to developing false memories. These results not only have theoretical implications for our understanding of memory, but also practical implications for the hundreds of millions of people worldwide who speak two or more languages.

For the first study, the team recruited 120 Chinese students who were studying in the US. On average, they had started learning English at the age of 9 and they rated their proficiency in English as about 5 on a scale of 1-7, with 7 being highly proficient.

Across two separate trials, each participant listened to two different sets of 15 words, one set in English, the other in Mandarin Chinese. Both sets contained words with related meanings, but omitted a word with a very closely related meaning, known as the ‘critical lure’. For example, a list that included the words rest, bed, drowsy, doze, tired, and awake omitted the word sleep. Earlier work has found that people are susceptible to falsely recalling critical lures as having been on the list.

After listening to a set of words, the participants wrote down all the words that they believed had been on the list and, in another column, any words that came to mind but that they did not think had been on the list.

The team’s analysis showed that, when working in English, the participants were more likely to put the critical lure in the ‘not on the list’ column than in the ‘on the list’ column. This suggests that they were better at monitoring their memories for accuracy when they were working in a foreign language.

In the second study, a fresh group of 120 native Mandarin Chinese speakers who also knew English watched two silent movie clips then listened to narratives describing what had happened in the clips. Each narrative contained a number of false details and also statements that were correct but that didn’t contain a key detail that the participants were then questioned on in a subsequent memory task. In this task, they were also asked about details from the videos that the narrative had got wrong.

The researchers found that when the participants were working in their native Mandarin Chinese, false details given in the narratives induced false memories of what had happened in the videos. However, when they were working in English, this ‘misinformation effect’ on memory all but disappeared. Their analysis also showed that using a foreign language didn’t boost the accuracy of the participants’ memory for the clips overall — rather, it purely enhanced their ability to detect false information.

Other studies have found that when we use a foreign language, we make different choices. For example, we are more likely to choose to sacrifice one life to save many, reject superstitious beliefs, and to eat unappealing but sustainable insect-based foods.

One explanation for these findings is that because it takes a little longer to process information in a foreign language, people are less susceptible to defaulting to quick, intuitive, potentially biased responses, and more likely to engage in slower, more deliberate, and more accurate, decision-making. The authors note that the quick, intuitive ‘System 1’ type of processing is known to increase susceptibility to errors, so if working in a foreign languages means that it is less likely to be used, this could explain these new results, too.

There are some limitations to this new research, however. All the participants spoke Mandarin Chinese and English, so clearly work is needed on speakers of other languages, too. Also, the participants in this study were good at English, though not fluent. A person’s level of fluency with their non-native language will likely affect the influence of language on false memories. Further studies will also be needed to explore this.

For now, though, this new work does suggest that after a meeting, say, conducted in English, a native English speaker may come away with a different — and less accurate — memory of what was decided than a colleague for whom English is their second language.

Given the sheer number of people worldwide who speak more than one language, and the number of companies with bases in different countries that use a single working language, further studies on the influence of language on false memories will clearly be important. Holiday-makers, too, may want to take note. Even if your school French or Spanish is a little rusty, this study offers another reason to make an effort to use it.

Read the paper in full: https://doi.org/10.1037/xge0001378