One thing at a time!

 It’s popular to think that you are multi-tasking, but the research is clear that people actually can’t multi-task,
One thing at a time – For many years the psychology research has shown that people can only attend to one task at a time. The research shows that people can attend to only one cognitive task at a time. You can only be thinking about one thing at a time. You can only be conducting one mental activity at a time. So you can be talking or you can be reading. You can be reading or you can be typing. You can be listening or you can be reading. One thing at a time.

We fool ourselves – We are pretty good at switching back and forth quickly, so we THINK we are actually multi-tasking, but in reality we are not.
  
The one exception:According to one research though, it has been considered true that there is one exception of "walking and talking" side by side..that too after a person is well practiced.
 Even this was negated later on though. A study showed that people talking on their cell phones while walking, run into people more often and don’t notice what is around them. The researchers had someone in a clown suit ride a unicycle. The people talking on a cell phone were much less likely to notice or remember the clown.

Info and Image collected from businessinsider.com..People interested in this finding should switch their channels to National Geographic quite often as they show very informative programs about this.