(Flickr user André Natta )

On first reading, most restaurant reviews on a site like Yelp do just that — they review restaurants. They assign stars and appraise empanadas and out the places with awful service. But they also say a surprising amount about the people writing them.

For instance: Diners reviewing pricey restaurants are more likely to write long-winded reviews using big words, subtly depicting themselves as educated food connoisseurs. Diners reviewing bad restaurants spin narratives of another kind in which they portray themselves as — seriously — victims of trauma.

This is the takeaway of an amusing study (good for a lunchtime read) in the online journal First Monday by researchers at Stanford and Carnegie Mellon. They analyzed the "linguistic structure" of nearly 900,000 Yelp reviews spanning five years, some 6,500 restaurants in seven U.S. cities, and every kind of dining option from greasy carry-out spots to fine purveyors of "New American" cuisine.

Among the other findings: Good reviews of expensive restaurants tend to tap metaphors about sex and sensuality ("these oysters are so seductive"). Good reviews of cheap places, on the other hand, go for the drug and addiction analogies ("this pizza is my crack").

All of the results suggest that we're as interested in saying something about ourselves — or, as the academics put it, the self — as we are in talking about the food. In assessing restaurants, we're intimately wrapped up in assessing ourselves as metaphorical addicts or spurned victims or appreciators of fancy things.

The trauma findings are particularly interesting. One-star reviews were heavy on negative emotions and collective grievance, with stories more of bad things that happened than bad food eaten ("we were ignored until we flagged down one waiter to go get our waitress"). This is, incidentally, also how we talk about tragedies and disasters. Here are the authors, Dan Jurafsky, Victor Chahuneau, Bryan R. Routledge and Noah A. Smith:

This exact constellation of features (negatively emotional past tense narratives about other people, with an associated increase in the first person plural) has been associated in a number of previous studies with a particular genre: people writing after experiencing trauma. According to the standard social stage model of coping (Pennebaker and Harber, 1993), shortly after a disaster or tragedy people experience emotional upheavals and obsessive thoughts and feelings. In this phase they share these thoughts and feelings with others, including strangers, and the phase is marked by expressions of collectively shared grief, in which people seem to emphasize their belonging to groups, using the words we or us with high frequency, as a sign of solidarity and other-comforting and a way of achieving “collective closure.”

Heady stuff for an overcooked burger, no? Restaurateurs should beware (although the good news here is that they might ease all this trauma with marginally better service, not new menus).

As for the language used in contented reviews, this pattern is intriguing:

The cheap good eats prompted a lot of variations on addiction, craving, chocoholics, jonesing, bingeing, drugs of choice, food crack and edible crack. The good expensive restaurants, meanwhile, included a lot of food that was erotic, pornographic, orgasmic, tempting, voluptuous, sinful, sultry and sexy (evidently not words you would use to describe a two-dollar slice of pizza).

Then you've got the really fancy people who appreciate "unobtrusive" service or well-appointed "vestibules" or food that's "commensurate" with its price tag:

Jurafsky et al.

A good follow-up study might look at how you review restaurants after you'd read this study. Surely there's a whole other language for the awkwardly self-conscious diner who knows that science is out there reading in between the lines of your burrito review.