Bishop George Berkeley's famous phrase, "to be is to be perceived" suggests that the things that exist in the world is merely perceptions of reality. Things exist because they have been perceived by someone. By thinking or having an idea, we have immediately perceive it.
James Boswell disagreed with his famous sentence, "I refute it thus!", and a phrase from an unknown source cited, "If a tree falls in the forest, and there is no one there to hear it, does it make a sound?" This was an attempt to show that things can exist independently from the perceiver.
My thought, as a response to that sentence, is that, well, how do we know that there is a sound when a tree falls in the forest? Because we, or someone out there, have perceived it so, through past experiences, or connecting the dots of cause and effect. Thus, for us to even ask the question, the reality has been perceived. I have not read anything that Berkeley wrote, but I believe that Berkeley's idea on this matter is much broader than that single example.
I am not a follower of Berkeley's, I merely had a thought while reading these people's stories.