Your brain sends out vibrations all the time, and your thoughts affect your life and other people's. They pick up these thoughts and get changed by them. That's why, say, a pacifist gets caught up in a riot situation. It's a field of vibrations - you can 'feel' someone else's thoughts when close to them.
Our thoughts are mainly controlled by our subconscious, which is largely formed before the age of 6, and you cannot change the subconscious mind by just thinking about it. That's why the power of positive thinking will not work for most people. The subconscious mind is like a tape player. Until you change the tape, it will not change.
What's very interesting is that when we look at human bodies, we look at our body as a singular entity when it turns out, no, if I could reduce us to a small size as the size of a cell and put you inside your body, rather than seeing a singular entity, what you would see is a metropolis with 50 trillion citizens.