There's a million important things going on in the world and in our lives, but we're really only aware of seven of them. This means that we all have a very narrow and limited understanding of the world and our own lives. The seven things on our mind all seem very important, while everything else is just kind of forgotten....

This seven register limitation also makes people very subject to manipulation. If you can control what is getting loaded into their attention, you can largely control what they think and how they feel. For example, if people keep talking about Iran and how scary they are and debating what to do about them, then pretty soon Iran will seem like the biggest, scariest problem in the world, and no solution will seem too extreme. The truth is that there are probably 100 more important problems, but it won't seem that way because all seven registers are loaded with the same topic. The subject of the debate is more important than the content. - Paul Buchheit (emphasis his)