Itullian:
You are correct. Our eyes are not senders, they are receivers. They do receive light, and then we see.
I think the problem comes in with the working definition of the word “observe” as you used it. In the everyday language, when we say observe, we usually mean: to see with our eyes. But this is not how science uses the word.
Let’s take the process of observing back one step. Before the light is received in our eyes, it bounces of the things in the room. If you look at someone through a mirror, what is it you are seeing? You are receiving the light that has bounced off the person’s face, then bounced off the mirror and has entered your retinas. You haven’t done anything. The LIGHT has done everything, e.g. bounced, reflected.
When you say “behavior”, in science speak, this usually refers to the speed and direction a particle is moving.
When you say “Observing a sub-atomic particle changes its behavior”, what this really means (in physics, at least), is more like
“When you hit a cue ball off of another billiard ball on a table, the billiard ball is deflected and moves away from the cue ball”
Aelred Minor: This really does not have much to do with the type of experiment, as much as a fundamental principle of observation. I can work out the math for you for the mechanism in physics for which I believe you are looking for, if you would like.