Your brain is made to focus on one thing at a time. Technology can multitask, but your brain cannot. For example, talking on your cellphone while driving causes your sight to narrow considerably. It even continues well after you have stopped talking.
“Scientists now know that the brain is incapable of paying attention to two things at the same time. What looks like multitasking is really switching back and forth between multiple tasks which reduces productivity and increases mistakes by up to 50%.” – Ifor Got