We often think that multitasking, or trying to undertake multiple activities at the same time, can help us better keep up with school or work demands—and, perhaps, is even necessary to learn new material in today’s modern world. Yet, studies consistently show that human beings are terrible multitaskers. When we attempt to do more than one thing at once, valuable information, without fail, falls through the cracks. People have a hard time believing this, however—everyone seems to think they are great at multi-tasking, even when shown evidence to the contrary.

Neuroscientists have tried to train people to be better multitaskers, especially now that so many of us are forever tethered to smart devices that ping, beep, and alert every few minutes, taking our attention away from our primary task. While those studies suggest that we may not completely fail when we mix tasks that involve distinct types of cognitive resources (e.g., walking while talking with a friend or doing math while listening to music), they still involve a whole lot of cognitive delegation. The brain still has to figure out where to direct our attention. Because of that, multitasking always comes at some cost. For optimal learning, it’s best to focus on one thing at a time.