”We can learn new languages while we sleep.“ This concept, announced in the headline of the article published 2014 in the UK Version of the Wired, sounds like a dream come true for most people. The ability to acquire a new language while sleeping, which would mean without any effort or specific time investment, might open various possibilities. Unfortunately, the title of the article written by Liat Clarke is not only misleading; the statement itself is wrong. When the article was published, Clarke worked as a reporter for the Wired UK, by now she is a deputy editor for the magazine who frequently publishes articles about a variety of topics, for example politics, neuroscience and technology.
Although the article was published three years ago, I decided to work out the facts as there has been no other popular science article to this topic recently nor did anyone publish a fact-check of it. Furthermore, it is related to my research topic involving incidental vocabulary learning.
The scientific papers
The article uses three different scientific papers as sources and combines the results in order to support its claim. The first and main paper is a written by Thomas Schreiner and Björn Rasch (2015), published in Cerebral Cortex. In their study, it was shown that German native speakers who learned Dutch words before going to sleep benefited from listening to the same words during the Non-REM (rapid eye movement) sleep, thus recalling the cued words better than the control group and the group that listened to the words while being awake. Their results show that verbal cueing seems to reactivate the related memories and facilitate the recall later on.
The second and third paper are only briefly mentioned and only the research institutes together with their locations and the year of the publication are specified (Northwestern University and Weizmann Institute of Science, respectively). The former is written by Rudoy et al. (2009), the latter by Arzi et al. (2012).
The study by Rudoy et al. (2009) resembles the study by Schreiner and Rasch, as they had their participants listening to some of the sounds that have been associated to locations before. Their results also show higher accuracy for the objects that were cued during sleep.
Arzi et al. (2012) show that their participants are able to remember odors that were associated with sounds during their sleep, claiming that humans are able to learn new information while being asleep.
The presentation in the article
The author mainly focused on the article by Schreiner and Rasch, reporting their research in more detail. In general, she presents the results from the paper correctly (and oversimplified), except for the assumption, why the sleep deprivation in the groups that had to stay awake may be dismissed as a relevant factor for the lower recall ability. As an explanation, she quotes the information Schreiner and Rasch provided about the EEG measurements in the abstract of the paper, although these measurements only show that the brain, even when the participant was asleep, seemed to go through the same process of memory encoding and language processing as it would in an awake state. Schreiner and Rasch, however, explain to disregard the partial sleep deprivation, since their participants were students who frequently stayed up long at night and the brain regions affected by sleep deprivations were not the same as the ones that seemed to cause the benefit for cueing during sleep.
Generally, all the quotes Clarke uses are from the abstract of the paper, which might lead to the question how thoroughly she read the paper in the first place. Especially, as the quotes are not quite properly incorporated in her writing, in my opinion. Another question that came to mind, is if there has been an interview with Rasch. Not only is he the only researcher mentioned, although he is the second author of the paper in question, but also she once seems to cite him directly. On the other hand, this quote might also just be a strongly simplified version of the final sentence of the scientific paper. If there has been an interview, I might do the author injustice regarding explanation of the sleep deprivation above; maybe it was explained differently.
Concerning the affiliation of the researchers, Clarke states that they are in „a team from the Swiss National Science Foundation (SNSF)“. To be honest, I am unsure about the way this kind of information is supposed to be presented. While the project was funded with a grant from the SNSF, the researchers are said to be employed by the University of Zurich.
In the last paragraph, Clarke mentions the other studies (Ruody et al. 2009; Arzi et al. 2012) in order to provide background for learning while sleeping. Even though she never repeats the statement in the title, by combining the articles she leads readers to the final assumption that languages can be learned without previous knowledge during sleep; she does not try to moderate this in any way. However, this has not been implied by none of the scientists; Schreiner and Rasch only state that vocabulary learning could be enhanced by verbal cueing during sleep.
In conclusion, the facts in the article are not wrong per se, but merely oversimplified compared to the original papers. The ”real“ falsehood of the paper is in the wording of the (click-bait) title and the combination of different scientific papers that might lead to this claim.
Interesting (or ”Fun“) Fact: This popular science article seems to be almost copied by James Vincent, writing a very similar article on the same day for The Independent, where he also refers back to the Wired UK article. On the one hand, the headline and the first paragraph are even more drastically incorrect, by claiming the wrong statement has been made by the researchers (”Yes, you can learn a foreign language in your sleep, say Swiss psychologists. On the other hand, this article explicitly qualifies the statement by explaining that previous input is necessary in order to achieve these results.
Arzi, A., Shedlesky, L., Ben-Shaul, M., Nasser, K., Oksenberg, A., Hairston, I. S., & Sobel, N. (2012). Humans can learn new information during sleep. Nature neuroscience, 15(10), 1460-1465.
Clarke, L. (2014, June 30) We can learn new languages while we sleep. Wired UK, Retrieved from http://www.wired.co.uk/article/learn-languages-while-you-sleep
Rudoy, J. D., Voss, J. L., Westerberg, C. E., & Paller, K. A. (2009). Strengthening individual memories by reactivating them during sleep. Science, 326(5956), 1079-1079.
Schreiner, T., & Rasch, B. (2015). Boosting vocabulary learning by verbal cueing during sleep. Cerebral Cortex, 25(11), 4169-4179.
Vincent, J. (2014, June 30) Yes, you can learn a foreign language in your sleep, say Swiss psychologists. The Independent, Retrieved from http://www.independent.co.uk/news/science/yes-you-can-learn-a-foreign-language-in-your-sleep-say-swiss-psychologists-9574112.html