A different take on the placebo effect. Give it a skim… It’s an interesting read:

Expectations have long been a topic of psychological research, and it’s well known that they affect how we react to events, or how we respond to medication. But in recent years, scientists have been intensively studying how expectations shape our direct experience of the world, what we taste, feel, and hear. The findings have been surprising - did you know that generic drugs can be less effective merely because they cost less? - and it’s now becoming clear just how pervasive the effects of expectation are.

The human brain, research suggests, isn’t built for objectivity. The brain doesn’t passively take in perceptions. Rather, brain regions involved in developing expectations can systematically alter the activity of areas involved in sensation. The cortex is “cooking the books,” adjusting its own inputs depending on what it expects. [...]

A similar mental process helps explain a wide variety of seemingly bizarre consumer behaviors. Baba Shiv, a neuroeconomist at Stanford, supplied people with an “energy” drink containing a potent brew of sugar and caffeine. Some participants paid full price for the drinks, while others were offered a discount. The participants were then asked to solve a series of word puzzles. To Shiv’s surprise, the people who paid discounted prices consistently solved fewer puzzles than the people who paid full price for the drinks, even though the drinks were identical.

In short, perception really is everything.