Many times, we think we are multitasking well and we aren’t. A study by Ira Hyman (2009) showed that people walking while talking on cell phones ran into people (literally) more often, and were less likely to notice what was around them than people who were not talking on cell phones. The researchers had someone in a clown suit ride by on a unicycle. The people talking on a cell phone were much less likely to notice or remember the clown than those who were not multitasking,
Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter) by Susan Weinschenk