Not long ago I signed up for an improvisational theater class. I thought I might gain stage presence and confidence; little did I know I would encounter a genuine cognitive challenge. Within seconds of stepping into a new scene, you must assign yourself a character, convey a location and jump into an activity. You must also react convincingly to your scene partners responses. Spinning a believable narrative out of two actors choices is like keeping a beach ball aloft no matter what awkward trajectory it may have spun off on.

Learning improv has brought home two main ideas of this issue. Pursuing all the goals needed to improvise a scene can feel just as demanding as, say, answering an important e-mail while taking a phone call. Clearly, I am not a supertaskerone of those rare people who can flawlessly execute multiple challenges at once. Psychologists David L. Strayer and Jason M. Watson study these lucky individuals, and they share their discoveries in Supertaskers and the Multitasking Brain."

To build a convincing scene, improvisers tune their eyes and ears to the thoughts and emotions of the other performers. The special section Sensational Senses, starting on page 44, explores the bedrock of that ability. The brain possesses sensory skills far more exotic than what we usually think of as sight, smell, hearing and taste, as journalist Ariel Bleicher writes in Edges of Perception." Some of the clues gleaned by our senses enable us to form social bonds, as psychologists Janina Seubert and Christina Regenbogen explain in I Know How You Feel." Years later those perceptions can act like landmines in the brain, unearthing a trove of memories. Delve into Maria Konnikovas Smells Like Old Times.

These themes are deeply related. The act of multitasking alters how we perceive the world as we travel through it. Multitasking divides our attention, which forces the brain to discard critical sensory signals and influences how we think. To engage fully in an experience, however, all you need to do is focus.