(Nautil) - Galileo Galilei is best known for his novel way of looking at Earth’s place in the solar system and his consequent problems with the Vatican. But long before all the fuss blew up over his cosmology, Galileo told us that while the physical attributes of the planet are present, they are perceptually nonexistent until they have been interpreted by our senses. This theory applies to wine as much as to anything else, and Galileo, who described wine as “sunlight, held together by water,” did not forget that fact. As he put it, “A wine’s good taste does not belong to the objective determinations of the wine and hence of an object, even of an object considered as appearance, but belongs to the special character of the sense in the subject who is enjoying this taste.”

Anyone who has ever attended a wine event knows the five S’s of wine tasting: See, Swirl, Sniff, Sip, Savor. The five S’s allow us to directly hit three of our five senses—sight, smell, and taste. This leaves us with two senses that we rarely associate with wine—hearing and touching. But ignoring them is a mistake. There are few things more satisfying than the classic Pop! of a Champagne bottle, however déclassé purists may consider it (they prefer an unostentatious hiss). More important, what a person has heard about a wine usually influences his or her perception of it. In fact, the multimillion-dollar wine advertising industry depends on this aspect of wine appreciation. As for that fifth sense, touch is also critically important in how we perceive wine—not through our fingers but through touch sensors in our mouths and throats. If we couldn’t feel the wine in our mouths, our experience of it would be incomplete.

The role that our senses play in our attraction to and appreciation of wine has been illuminated by generations of wine writers and critics. What has undeservedly received less attention is the brain, the hugely complex organ within which all that sensory information is processed and synthesized. We don’t just taste with our senses, we taste with our minds. And our minds are routinely affected by a host of influences of which, quite often, we are not even aware. Both our senses and our common sense can be led astray by any number of extraneous factors originating in what we know, or think we know, about the wine we are drinking. Figuring out how our minds work in such complex domains as the evaluation of wines—which are, among other things, economic goods—is the province of neuroeconomics.

Researchers discovered that individuals on average enjoy more expensive wines slightly less.

To study the relationship between consumer preference and, for example, the cost of wine, neuroeconomists typically set up blind experiments, in which the subjects are unaware of the parameters of the experiment. Researchers at the Stockholm School of Economics and Yale University have conducted a double-blind experiment—in which both the subject and the experimenters with whom they come into contact are unaware of the parameters involved—upon this relationship. Their sample of over 500 subjects included experts, casual wine drinkers, and novices. The experiment was simple. Subjects were asked to taste a succession of wines and rate them as Bad, Okay, Good, or Great. The wines ranged in price from $1.65 to $150, and the subjects were not told the cost. The responses for each wine were tabulated, and statistical analyses applied. Now, the average wine buyer might have hoped that this experiment would show that the price of a wine is correlated with its quality. This would certainly simplify life. But the researchers discovered that “the correlation between price and overall rating is small and negative, suggesting that individuals on average enjoy more expensive wines slightly less.”

To explore this relationship further, researchers at the California Institute of Technology set up an experiment in which they examined not only the dynamics of preference but also which regions of the brain might be controlling such preferences, in light of cost. To localize these, they turned to functional magnetic resonance imaging (fMRI). The tough part of using this method on taste judgments is that the subject has to lie completely still, so the researchers had to devise a pump-and-tube system to deliver the wine to their subjects. Then the researchers threw a complication into the study that allowed them to pinpoint whether knowledge of price affected perceptions of taste.

First, they bought Cabernet Sauvignon from three different vineyards: an expensive $90 bottle, an intermediate $35 bottle, and a rock-bottom $5 bottle. Their subjects were all young wine-drinkers (aged 21 to 30) who both liked and occasionally drank red wine, but were not alcoholics. They placed the subjects in their MRI machine, connected the delivery hoses, and told them they were going to taste five different kinds of Cabernet Sauvignon. For each of the offerings the subjects were told the notional cost of the wine (as listed in the table), and then the wines were pumped into the subjects’ mouths in a predetermined sequence, for a set amount of time. Subjects were then asked a series of questions designed to determine their preference for each of the “five” wines. The experiment confirmed that perceived wine cost was a heavy factor in choosing preferences. But the real revelation was that a region of the brain called the medial orbitofrontal cortex was hyperactive in every one of the subjects while he was making his choice. It seems that we all use the same part of the brain to make decisions about wine, at least when money is involved.

This experiment clearly showed that the subjects’ preferences for the wines used in the study were strongly influenced by what they believed the wines had cost, and that this calculation was processed in a specific part of the brain. That’s a start. But the subjects were relatively young and naive about wine tasting, and one might legitimately wonder whether an expert wine connoisseur would have been tricked in the same way. This experiment has not been performed yet, at least with an fMRI machine. But it seems likely from the literature that prior knowledge is a significant factor in most people’s appreciation of a wine.

The psychologist Antonia Mantonakis and her colleagues looked at preconceived notions from another perspective. Before giving the subjects wine to taste, the researchers first planted in their subjects’ minds either the notion that they had previously “loved the experience” of drinking wine or that they had “got sick” from it. Whether the subjects actually remembered their earlier drinking experiences in either way was irrelevant to the experiment, since virtually everyone has had experiences of both kinds at some time in their wine-drinking lives. What was important was the initial suggestion offered to the subjects. And the outcome was perhaps to be expected: People who were given the positive suggestion were more influenced by it, and consumed more wine than those who received the negative one. Clearly, the tasters’ responses were affected by extraneous factors, and the recommendation to retailers was that in selling wine they should try to call up the most pleasant possible associations in their customers’ minds.