From an article in Psychology Today (https://www.psychologytoday.com/sg/blog/the-athletes-way/201706/are-smartphones-making-us-stupid): > During this study, the UT Austin researchers found that someone’s ability to hold and process data significantly improved if his or her smartphone was in another room while taking a test to gauge attentional control and cognitive processes. Participants who kept their phones in a pocket or bag also outperformed those who kept their phones on the desk while taking the same test. Again, even if the phone was turned off and face down on the desk, the mere sight of one's own smartphone seemed to induce “brain drain” by depleting finite cognitive resources. The study in question: Ward, Adrian F., Kristen Duke, Ayelet Gneezy, and Maarten W. Bos. “Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity.” Journal of the Association for Consumer Research 2, no. 2 (April 2017): 140–54. https://doi.org/10.1086/691462.