Cheap or expensive pills?

This time I heard something i think all of us had sometime pass trough, what kind of medicine choose?, that one that is expensive, the "original" or that one that is cheaper the generic. I heard about a research that had been made in The Massachusetts Technology Institute in USA, in which they tried to prove the placebo effect of pills in humans. In this experiment researchers produced some kind of pain in people and then told them they will take a pain killer and gave them 4 kinds of different pills, they told them the first one was cheap and made in china, the second one was expensive and made in china, the third one was cheap and made in USA and the forth one was expensive and made in USA, after every time they gave them the pill they produced them pain again and ask them how painful was it every time, and they concluded that people felt less pain when they took the expensive pill than those who take the cheaper, but at the end of the experiment they told them that pills were not pain killers it were only placebos (pills without medicine, just sugar). Another research explain this experiment, they said that everytime we take a pill and we know something that make us trust in it our body release opioids something like morphine that helped us to finish with the pain, thats why everybody thinks that expensive pills works better than cheaper pills although they had the same content.