This may not be related to audio. If you, let's say, decide to try a nutritional product, claimed to increase your energy, I think it's important that you have a positive bias, when you take it. People will say it is the placebo effect, but I think, in order get the full benefit of that product, you actually have to have a positive bias. Time will tell you what is correct, but I've seen negative bias interfere more(because they stop experimenting with that product) with finding the truth.
