My understanding of the phenomenon, (full disclosure, I haven't actually done the experiment nor know anyone who has, GASP!) is that the act of observing is absorbing or altering photons in the process of measuring which affects the measurement.  Yes we are part of the universe, but i believe only in a measuring kind of way and not the transcendental way.  but you never know for sure... "it is thee that hath made us and not we ourselves" (not to discount the participatory nature of being)... 

 I love this phenomenon and any thinking around it. Personally I don't think we "absorb photons" and so alter the state. 

I am more wondering what is an act of observing? 

I don't think the experiment will change if we put a chair there... But what about a plant.. Or ant.. Or Another mamal?