Great read over at Louie Mantia’s blog.
“While a computer can simultaneously run two applications at once, this does not mean a human can perform tasks in both applications simultaneously. For example, you cannot type two different messages in two different windows at the same exact time. While you are able to easily switch to another chat window or tab, you are not actually performing both tasks at the same time. Similarly, you are not able to read a tweet and read an article in your RSS feed simultaneously.
On a sidetone, take this into “real life.” You know when you’re with a friend in a busy coffee shop, and there’s a bunch of people talking? You focus on what your friend is saying while filtering out all the other people. It’s really hard (if not impossible) to truly listen to two people talking at the same time. Similarly, it is with your eyes. Try playing Super Mario Bros. while reading a book. Yeah, that didn’t work out so well. Your eyes are required in two locations. Remember when you were a kid and someone told you to try to rub your tummy and pat your head? Similar stuff, here. It’s impossible to give your full attention to multiple things. You can, however, sacrifice and divide your attention.”