The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people (“source control”) with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.

Can mobile-assisted language learning (MALL) foster self-directed learning outside the classroom? This article examines informal, out-of-class engagement with a MALL tool: Duolingo. After being invited to use Duolingo, 118 higher education language students agreed to have their activity in the application tracked. In addition to the data collected from the Duolingo dashboard, questionnaires, as well as semi-structured interviews, were implemented. Results viewed from Garrison’s dimensions of self-directed learning (motivation, self-management and self-monitoring) reveal inconsistencies between what students think about the app and what they do with it. Questionnaires suggest that Duolingo can encourage out-of-class learning through fun activities, but interviews reveal a lack of sustained motivation, self-monitoring and self-management reflected in the low usage of the application. Tracking data reveals that students lack the time for out-of-class MALL during course weeks and are more active during holidays. The results highlight the importance of a context in which users are encouraged to take responsibility for their learning. However, most students will, besides encouragement, also need training and support for their self-directed learning.

Learners need diligence when going solo in technology-enhanced learning environments. Nevertheless, self-regulation and scaffolding are two under-researched concepts when it comes to mobile learning. To tackle this knowledge gap, this study focuses on self-regulation and scaffolding for mobile assisted language learning (MALL). Fifty-two students of French as a foreign language were divided into one control and two experimental groups. The two experimental groups were invited to engage in voluntary language learning through a language platform, Duolingo. One of the two experimental groups was trained for self-regulation and received scaffolding for their MALL. The study reveals five main findings: First, students who were trained in self-regulation and received temporary scaffolding present a significantly higher participation in Duolingo. Second, self-regulation features provided by Duolingo are not frequently used by students and therefore do not substantially contribute to students’ own learning micromanagement. Third, there is a correlation between high use of Duolingo and improvement in French writing skills. Fourth, just inviting students to engage in voluntary out-of-class MALL does not result in higher test scores for French listening, reading or writing skills. Fifth, in a MALL context, self-regulation training and temporary scaffolding contribute to higher test scores in French writing. Overall, the results suggest that training and scaffolding for self-regulation is beneficial in a voluntary out-of-class MALL context. However, more research is needed to analyze in which conditions voluntary out-of-class MALL can lead to substantial learning improvements.