For computers, as for humans, reading and observation are two distinct ways to understand the world, Mr. Lieberman Aiden said. In that sense, he said, “computers don’t have one hand tied behind their backs anymore.”
Text has been easier for A.I. to handle, because words have discrete characters — 26 letters, in the case of English. That makes it much closer to the natural language of computers than the freehand chaos of imagery. But image recognition technology, much of it developed by major technology companies, has improved greatly in recent years.
The Stanford project gives a glimpse at the potential. By pulling the vehicles’ makes, models and years from the images, and then linking that information with other data sources, the project was able to predict factors like pollution and voting patterns at the neighborhood level.
“This kind of social analysis using image data is a new tool to draw insights,” said Timnit Gebru, who led the Stanford research effort. The research has been published in stages, the most recent in late November in the Proceedings of the National Academy of Sciences.
In the end, the car-image project involved 50 million images of street scenes gathered from Google Street View. In them, 22 million cars were identified, and then classified into more than 2,600 categories like their make and model, located in more than 3,000 ZIP codes and 39,000 voting districts.
But first, a database curated by humans had to train the A.I. software to understand the images.
The researchers recruited hundreds of people to pick out and classify cars in a sample of millions of pictures. Some of the online contractors did simple tasks like identifying the cars in images. Others were car experts who knew nuances like the subtle difference in the taillights on the 2007 and 2008 Honda Accords.
“Collecting and labeling a large data set is the most painful thing you can do in our field,” said Ms. Gebru, who received her Ph.D. from Stanford in September and now works for Microsoft Research.
But without experiencing that data-wrangling work, she added, “you don’t understand what is impeding progress in A.I. in the real world.”
Once the car-image engine was built, its speed and predictive accuracy was impressive. It successfully classified the cars in the 50 million images in two weeks. That task would take a human expert, spending 10 seconds per image, more than 15 years.
Identifying so many car images in such detail was a technical feat. But it was linking that new data set to public collections of socioeconomic and environmental information, and then tweaking the software to spot patterns and correlations, that makes the Stanford project part of what computer scientists see as the broader application of image data.
“There has been an explosion of computer vision research, but so far the societal impact has been largely absent,” said Serge Belongie, a computer scientist at Cornell Tech. “Being able to identify what is in a photo is not science that advances our understanding of the world.”
The Stanford car project generated a host of intriguing connections, not so much startling revelations. In the most recent paper, and one published earlier in the year by the Association for the Advancement of Artificial Intelligence, these were among the predictive correlations:
■ The system was able to accurately predict income, race, education and voting patterns at the ZIP code and precinct level in cities across the country.
■ Car attributes (including miles-per-gallon ratings) found that the greenest city in America is Burlington, Vt., while Casper, Wyo., has the largest per-capita carbon footprint.
■ Chicago is the city with the highest level of income segregation, with large clusters of expensive and cheap cars in different neighborhoods; Jacksonville, Fla., is the least segregated by income.
■ New York is the city with the most expensive cars. El Paso has the highest percentage of Hummers. San Francisco has the highest percentage of foreign cars.
Other researchers have used Google Street View data for visual clues for factors that influence urban development, ethnic shifts in local communities and public health. But the Stanford project appears to have used the most Street View images in the most detailed analysis so far.
The significance of the project, experts say, is a proof of concept — that new information can be gleaned from visual data with artificial intelligence software and plenty of human help.
The role of such research, they way, will be mainly to supplement traditional information sources like the government’s American Community Survey, the household surveys conducted by the Census Bureau.
This kind of research, if it expands, will raise issues of data access and privacy. The Stanford project only made predictions about neighborhoods, not about individuals. But privacy concerns about Street View pictures have been raised in Germany and elsewhere. Google says it handles research requests for access to large amounts of its image data on a case-by-case basis.
Onboard cameras in cars are just beginning, as auto companies seek to develop self-driving cars. Will some of the vast amounts of image data they collect be available for research or kept proprietary?
Kenneth Wachter, a professor of demography at the University of California, Berkeley, said image-based studies could be a big help now that public response rates to sample surveys are declining. An A.I.-assisted visual census, he said, could fill in gaps in the current data, but also provide more timely insights than the traditional census, conducted every 10 years, on hot topics in public policy like “the geography and evolution of disadvantage and opportunity.”
To Nikhil Naik, a computer scientist and research fellow at Harvard, who has used Street View images in the study of urban environments, the Stanford project points toward the future of image-fueled research.
“For the first time in history, we have the technology to extract insights from very large amounts of visual data,” Mr. Naik said. “But while the technology is exciting, computer scientists need to work closely with social scientists and others to make sure it’s useful.”