Contrary to the previous reviewer, it is precisely the fact that you have to constantly hear multiple streams of thought of a few people at the same time, and decide what is "noise" and what is "important" what made this movie most interesting and enjoyable for me.
It is a psychological experience that is exactly the opposite of what you normally do all day long... paying attention to the one stimulus that you already know is important in the given situation while what is not important automagically gets filtered out by your senses.
For a layperson (regarding the complex machinery of your senses) this movie gives you a "hands on" way of appreciating the valuable work your senses do for you all the time, filtering out irrelevant information for you. Even if you are acquainted with the science behind the senses, this movie shows you how you probably would go insane if this filtering were not part of our makeup.