Are our Minds Joined?

My 6 year-old son once out of the blue asked me whether thoughts are private? I had no clue what to answer so I just quoted the transition of a German song "The thoughts are free", which seemed reasonable enough, though quite honestly,  you certainly can appeal to the mind of another person even without her knowing. I often send little energy waves to people when I feel they need a little boost, the same applies to peace of mind, confidence and health. You can study the reactions of your brothers and sisters before and after, though I would recommend leaving this experiment personal in nature. So it seems our minds are joined after all; hope I can express myself better next time he asks.