In 2002, one of the most prestigious restaurants in New York City served four Wall Street workers its most expensive bottle of wine: a US$2,000 Mouton Rothschild from 1989.

After it was decanted, the host of the group, a self-reported wine connoisseur, twirled his glass, took a sip and began praising the wine for its purity. Blissfully ignorant, the group had accidentally been given the cheapest bottle of wine on the menu, a Pinot noir valued at just US$18.

This story might sound like a flight of fancy, but growing research on the psychology and neuroscience of wine-tasting suggests mistakes like this are made all the time, although true wine experts often know better.

One of the first studies to explicitly manipulate the price of wine in a realistic tasting session has found a cheap glass becomes far more pleasant when participants are told it has a higher price.

The experiment was conducted during a public event at the University of Basel in Switzerland. To entertain visitors, the psychology department kindly contributed a wine tasting session.

The event drew 140 participants throughout the day and consisted of a 15-minute session of wine tasting. For each tasting, participants were given their own table and told not to communicate with others also involved in the event - that way their views of the wine wouldn't be influenced.

Six small glasses of wine were then placed on each table, and visitors were told to taste each and every glass in a specific sequence fully randomized for every individual. After each sip, participants were instructed to clear their palates with a swish of water and rate the wine for pleasantness and intensity.

Half the glasses held three different wines without any price information. The remaining glasses contained three different wines of low, medium, and high price with the retail tag clear to see.

In each case, one, two or none of these price-tagged wines had been labeled deceptively. If they were mislabeled, the retail price displayed was either four times higher, or four times lower than the real cost.

When the price of the wine was hidden, researchers found no difference in pleasantness ratings, no matter the actual price.

On the other hand, when the price of wine was mislabeled and deceptively up-priced, pleasantness ratings also increased. For instance, when a low-cost wine was tagged to appear higher in price and exceeded that of the mid-priced wine, participants tended to enjoy the low-cost one more.

"Thus, in wine may lay the truth, but its subjective experience may also lie in the price," the authors conclude.

Beyond sheer enjoyment, this study is the first to assess the perceived intensity of blind tastings in a real world setting, and it suggests that most wine drinkers are able to determine something different about more expensive wine - they just don't enjoy that difference as much.

In short, while the intensity of expensive wine might taste more obvious, it seems the pleasantness of that glass doesn't always add up to the cost.

These results largely fall in line with previous studies, which have found manipulating wine prices can actually change how pleasant they taste, while the intensity of the wine stays relatively consistent with its price.

In 2008, researchers used functional MRI to scan participants while they tasted wines that were deceptively labeled. When the price of a wine was increased, participants reportedly enjoyed the flavor more, while intensity ratings remained the same.

In 2017, follow-up research was able to confirm these results. Scanning the brains of those tasting wines, researchers found increasing the price of the product once again improved subjective reports of flavor without changing its perceived intensity.

What's more, this deceptive pricing increased activity in the medial orbitofrontal cortex of the brain, which is thought to encode for experienced pleasantness.

"The reward and motivation system is activated more significantly with higher prices and apparently increases the taste experience in this way," said behavioral economist Bernd Weber from the University of Bonn in Germany in 2017.

Such studies have allowed us to better understand how marketing might influence our brains and our perceptions of pleasantness, but few experiments have replicated these effects in a real-world setting. Previous fMRI studies fed wine to participants through plastic tubes, which means the color and smell were not taken into account, just the price and taste.

This has helped narrow down confounding factors, but it also misses out on several of the ways experts normally judge wine.

The current study is more realistic, measuring both pleasantness and intensity "to get a more comprehensive understanding of the influence of price on consumer's experience."

Unlike previous studies, the authors found decreasing the price of an expensive wine by four fold did not change the overall wine ratings for its pleasantness among laypeople. Only when the price was deceptively increased, did the average person seem to prefer the wine more.

These differing results might have occurred because of the more realistic wine-tasting experience, which allowed participants to also take into account the smell and color of the wine they were drinking. The noise of the event might also have influenced their other senses, possibly reducing or canceling out the effects of the price information.

"These cues could have potentially lowered the impact of the price information on wine ratings, as participants did not only pay attention to the price information presented," the authors suggest.

The Wall Street workers who ordered their US$2,000 bottle of wine in 2002 are a good example of exactly this. Their table was in a celebratory mood, "clearly enhanced by the wine", before they were informed of the mistake.

When the owner of the restaurant told them and apologized, the host supposedly replied, "I THOUGHT that wasn't a Mouton Rothschild!"

Nearby, a young couple who ordered an US$18 bottle of wine found they were actually indulging in something far more expensive.

"Both parties left Balthazar happy that night, but the younger of the two left happier," the owner recalled on Instagram last year.

Sometimes, life is sweeter when you don't know the truth.

The study was published in Food Quality and Preference.