According to one hypothesis an experienced wine taster with knowledge and the experienced wine taster without knowledge, assuming they have the same biological capacities, smell and taste the same thing. The person with knowledge might be able to articulate what they experience and explain it more readily than the wine taster without knowledge but their perceptual experience is the same.
The alternative hypothesis is that wine knowledge helps us perceive features of the wine. When we know that, for instance, cool weather Cabernet has a bell pepper aroma we are better able to detect that aroma because we actively learn to suppress other signals coming from the wine until the bell pepper aroma is clear. I’ve always favored the second hypothesis based on my own experience but as far as I know there has been no definitive proof of it.
Jamie Goode points to some science supporting a third hypothesis:
There’s one very interesting molecule called androstenone. It’s associated with pigs, and it’s known colloquially as boar taint. [editors note: not found in wine afaik] Some people find it very unpleasant (they tend not to like eating pork), whereas others find it OK, and some people can’t smell it at all.
But there’s an interesting twist. If you take a person who is anosmic for androstenone and you repeatedly expose them to it, they won’t smell anything. But for some of them, after a while, they will begin to smell it when before they couldn’t.
One explanation for this is that even though they can’t smell androstenone, somehow exposure to it is up-regulating the expression of the gene that encodes the receptor, to the point where there’s enough signal for it to be perceived.
This third hypothesis that Jamie points to is that learning takes place, not because of new beliefs influencing our sensory mechanisms, but because repeated exposure shapes our biological capacities.
Of course the second and third hypotheses are compatible; they could both be true. But I guess Jamie’s hypothesis has a certain appeal—if you want to become a better taster don’t bother with the books and maps, just drink more wine.