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Conversation is the platform where minds meet to create and exchange ideas, hone norms, and forge bonds. But how do minds coordinate with each other to build a shared narrative from independent contributions? Here we show that when two people converse, their pupils periodically synchronize, marking moments of shared attention. As synchrony peaks, eye contact occurs and synchrony declines, only to recover as eye contact breaks. These findings suggest that eye contact may be a key mechanism for enabling the coordination of shared and independent modes of thought, allowing conversation to both cohere and evolve.

Shared by 41, including Uta Frith, Paul Graham, Paul Kedrosky

Wearing face masks and maintaining social distance are familiar to many people around the world during the ongoing SARS-CoV-2 pandemic. Evidence suggests that these are effective ways to reduce the risk of SARS-CoV-2 infection. However, it is not clear how exactly the risk of infection is affected by wearing a mask during close personal encounters or by social distancing without a mask. Our results show that face masks significantly reduce the risk of SARS-CoV-2 infection compared to social distancing. We find a very low risk of infection when everyone wears a face mask, even if it doesn’t fit perfectly on the face. Previously published data were used for this work (<https://aerosol.ds.mpg.de/>). All other study data are included in the article and/or [ SI Appendix ][1]. [1]: https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2110117118/-/DCSupplemental

Past research has found that experienced well-being does not increase above incomes of $75,000/y. This finding has been the focus of substantial attention from researchers and the general public, yet is based on a dataset with a measure of experienced well-being that may or may not be indicative of actual emotional experience (retrospective, dichotomous reports). Here, over one million real-time reports of experienced well-being from a large US sample show evidence that experienced well-being rises linearly with log income, with an equally steep slope above $80,000 as below it. This suggests that higher incomes may still have potential to improve people’s day-to-day well-being, rather than having already reached a plateau for many people in wealthy countries. Data aggregated by income level have been deposited in OSF (<https://accounts.osf.io/login?service=https://osf.io/nguwz/>) ([23][1]). Granular data are stored in a repository and are available to qualified researchers who wish to verify or extend the claims of this paper; contact the author for access information. [1]: #ref-23

The role of social media in political discourse has been the topic of intense scholarly and public debate. Politicians and commentators from all sides allege that Twitter’s algorithms amplify their opponents’ voices, or silence theirs. Policy makers and researchers have thus called for increased transparency on how algorithms influence exposure to political content on the platform. Based on a massive-scale experiment involving millions of Twitter users, a fine-grained analysis of political parties in seven countries, and 6.2 million news articles shared in the United States, this study carries out the most comprehensive audit of an algorithmic recommender system and its effects on political content. Results unveil that the political right enjoys higher amplification compared to the political left. Aggregated study data are available upon request from the corresponding authors following the protocol outlined in [ SI Appendix, section 3 ][1]. [1]: https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2025334119/-/DCSupplemental

COVID-19 has generated a huge mortality toll in the United States, with a disproportionate number of deaths occurring among the Black and Latino populations. Measures of life expectancy quantify these disparities in an easily interpretable way. We project that COVID-19 will reduce US life expectancy in 2020 by 1.13 y. Estimated reductions for the Black and Latino populations are 3 to 4 times that for Whites. Consequently, COVID-19 is expected to reverse over 10 y of progress made in closing the Black−White gap in life expectancy and reduce the previous Latino mortality advantage by over 70%. Some reduction in life expectancy may persist beyond 2020 because of continued COVID-19 mortality and long-term health, social, and economic impacts of the pandemic. All study data are included in [Dataset S1][1]. [1]: https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2014746118/-/DCSupplemental