There are many components of wine quality. Most are well-known to wine enthusiasts: color, balance, intensity, structure, length, complexity, ageability, for example. But one aspect, perhaps the one which most separates very good wine from great, and great from insanely great, is rarely talked about, even among winemakers and critics.
People tend to think a wine tastes better if they believe it's relatively pricey. Scientists are beginning to learn how our brains convert expectations to "real" perceptions.