In this post on the A Learning A Day daily blog by Rohan Rajiv the Pygmalion Effect is mentioned.
Pygmalion Effect, also called Rosenthal effect, says that if you and everyone around you believe in something, there are more chances of you making it happen. In other words, high expectation lead to better results while lower expectations lead to poorer. It is a bit similar to the Placebo effect in Medical Science.
Right now, there are 3 or more Vaccines with high efficacy are peeking from the horizon. While there are skeptics, there’s a huge populace which is betting on its success. Even if they end up being reasonable in effectiveness, this effect might make it more effective.
Same thing works with confidence. Isn’t it?