[FoRK] The Really Smart Phone
eugen at leitl.org
Thu Apr 28 03:30:02 PDT 2011
The Really Smart Phone
Researchers are harvesting a wealth of intimate detail from our cellphone
data, uncovering the hidden patterns of our social lives, travels, risk of
disease—even our political views.
By ROBERT LEE HOTZ
'Phones can know,' says an MIT researcher. 'People can get this god's-eye
view of human behavior.'
Apple and Google may be intensifying privacy concerns by tracking where and
when people use their mobile phones—but the true future of consumer
surveillance is taking shape inside the cellphones at a weather-stained
apartment complex in Cambridge, Mass.
For almost two years, Alex Pentland at the Massachusetts Institute of
Technology has tracked 60 families living in campus quarters via sensors and
software on their smartphones—recording their movements, relationships,
moods, health, calling habits and spending. In this wealth of intimate
detail, he is finding patterns of human behavior that could reveal how
millions of people interact at home, work and play.
Through these and other cellphone research projects, scientists are able to
pinpoint "influencers," the people most likely to make others change their
minds. The data can predict with uncanny accuracy where people are likely to
be at any given time in the future. Cellphone companies are already using
these techniques to predict—based on a customer's social circle of
friends—which people are most likely to defect to other carriers.
A wave of ambitious social-network experiments is underway in the U.S. and
Europe to track our movements, probe our relationships and, ultimately,
affect the individual choices we all make. WSJ's Robert Lee Hotz reports.
The data can reveal subtle symptoms of mental illness, foretell movements in
the Dow Jones Industrial Average, and chart the spread of political ideas as
they move through a community much like a contagious virus, research shows.
In Belgium, researchers say, cellphone data exposed a cultural split that is
driving a historic political crisis there.
And back at MIT, scientists who tracked student cellphones during the latest
presidential election were able to deduce that two people were talking about
politics, even though the researchers didn't know the content of the
conversation. By analyzing changes in movement and communication patterns,
researchers could also detect flu symptoms before the students themselves
realized they were getting sick.
"Phones can know," said Dr. Pentland, director of MIT's Human Dynamics
Laboratory, who helped pioneer the research. "People can get this god's-eye
view of human behavior."
So far, these studies only scratch the surface of human complexity.
Researchers are already exploring ways that the information gleaned from
mobile phones can improve public health, urban planning and marketing. At the
same time, researchers believe their findings hint at basic rules of human
interaction, and that poses new challenges to notions of privacy.
"We have always thought of individuals as being unpredictable," said Johan
Bollen, an expert in complex networks at Indiana University. "These
regularities [in behavior] allow systems to learn much more about us as
individuals than we would care for."
Today, almost three-quarters of the world's people carry a wireless phone.
That activity generates immense commercial databases that reveal the ways we
arrange ourselves into networks of power, money, love and trust. The patterns
allow researchers to see past our individual differences to forms of behavior
that shape us in common.
As a tool for field research, the cellphone is unique. Unlike a conventional
land-line telephone, a mobile phone usually is used by only one person, and
it stays with that person everywhere, throughout the day. Phone companies
routinely track a handset's location (in part to connect it to the nearest
cellphone tower) along with the timing and duration of phone calls and the
user's billing address.
Typically, the handset logs calling data, messaging activity, search requests
and online activities. Many smartphones also come equipped with sensors to
record movements, sense its proximity to other people with phones, detect
light levels, and take pictures or video. It usually also has a compass, a
gyroscope and an accelerometer to sense rotation and direction. What They
Advances in statistics, psychology and the science of social networks are
giving researchers the tools to find patterns of human dynamics too subtle to
detect by other means. At Northeastern University in Boston, network
physicists discovered just how predictable people could be by studying the
travel routines of 100,000 European mobile-phone users.
After analyzing more than 16 million records of call date, time and position,
the researchers determined that, taken together, people's movements appeared
to follow a mathematical pattern. The scientists said that, with enough
information about past movements, they could forecast someone's future
whereabouts with 93.6% accuracy.
The pattern held true whether people stayed close to home or traveled widely,
and wasn't affected by the phone user's age or gender.
"For us, people look like little particles that move in space and that
occasionally communicate with each other," said Northeastern physicist
Albert-Laszlo Barabasi, who led the experiment. "We have turned society into
a laboratory where behavior can be objectively followed."
Only recently have academics had the opportunity to study commercial
cellphone data. Until recently, most cellphone providers saw little value in
mining their own data for social relationships, researchers say. That's now
changing, although privacy laws restrict how the companies can share their
Several cellphone companies in Europe and Africa lately have donated large
blocks of calling records for research use, with people's names and personal
details stripped out.
"For the scientific purpose, we don't care who the people are," said medical
sociologist Nicholas Christakis at Harvard University, who is using phone
data to study how diseases, behavior and ideas spread through social
networks, and how companies can use these webs of relationships to influence
drug marketing and health-care decisions.
His work focuses on "social contagion"—the idea that our relationships with
people around us, which are readily mapped through cellphone usage, shape our
behavior in sometimes unexpected ways. By his calculation, for instance,
obesity is contagious. So is loneliness.
Even though the cellphone databases are described as anonymous, they can
contain revealing personal details when paired with other data. A recent
lawsuit in Germany offered a rare glimpse of routine phone tracking. Malte
Spitz, a Green party politician, sued Deutsche Telekom to see his own records
as part of an effort by Mr. Spitz to highlight privacy issues.
In a six-month period, the phone company had recorded Mr. Spitz's location
more than 35,000 times, according to data Mr. Spitz released in March. By
combining the phone data with public records, the news site Zeit Online
reconstructed his daily travels for months.
In recent days, Apple Inc. triggered privacy alarms with the news that its
iPhones automatically keep a database of the phone's location stretching back
for months. On Friday, The Wall Street Journal reported that both Apple and
Google Inc. (maker of the Android phone operating system) go further than
that and in fact collect location information from their smartphones. A test
of one Android phone showed that it recorded location data every few seconds
and transmitted it back to Google several times an hour.
Google and Apple have said the data transmitted by their phones is anonymous
and users can turn off location sharing.
"We can quantify human movement on a scale that wasn't possible before," said
Nathan Eagle, a research fellow at the Santa Fe Institute in New Mexico who
works with 220 mobile-phone companies in 80 countries. "I don't think anyone
has a handle on all the ramifications." His largest single research data set
encompasses 500 million people in Latin America, Africa and Europe.
Among other things, Mr. Eagle has used the data to determine how slums can be
a catalyst for a city's economic vitality. In short, slums provide more
opportunities for entrepreneurial activity than previously thought. Slums
"are economic springboards," he said.
Cellphone providers are openly exploring other possibilities. By mining their
calling records for social relationships among customers, several European
telephone companies discovered that people were five times more likely to
switch carriers if a friend had already switched, said Mr. Eagle, who works
with the firms. The companies now selectively target people for special
advertising based on friendships with people who dropped the service.
At AT&T, a research team led by Ramon Caceres recently amassed millions of
anonymous call records from hundreds of thousands of mobile-phone subscribers
in New York and Los Angeles to compare commuting habits in the two
Dr. Caceres, a lead scientist at AT&T Labs in Florham Park, N.J., wanted to
gauge the potential for energy conservation and urban planning. "If we can
prove the worth of this work, you can think of doing it for all the world's
billions of phones," he said.
Thousands of smartphone applications, or "apps," already take advantage of a
user's location data to forecast traffic congestion, rate restaurants, share
experiences and pictures, or localize radio channels. Atlanta-based AirSage
Inc. routinely tracks the movements of millions of cellphones to generate
live traffic reports in 127 U.S. cities, processing billions of anonymous
data points about location every day.
As more people access the Internet through their phones, the digital universe
of personal detail funneled through these handsets is expanding rapidly, and
so are ways researchers can use the information to gauge behavior. Dr. Bollen
and his colleagues, for example, found that the millions of Twitter messages
sent via mobile phones and computers every day captured swings in national
mood that presaged changes in the Dow Jones index up to six days in advance
with 87.6% accuracy.
The researchers analyzed the emotional content of words used in 9.7 million
of the terse 140-character text messages posted by 2.7 million tweeters
between March and December 2008. As Twitter goes, so goes the stock market,
the scientists found.
"It is not just about observing what is happening; it is about shaping what
is happening," said Dr. Bollen. "The patterns are allowing us to learn how to
better manipulate trends, opinions and mass psychology."
Some scientists are taking advantage of the smartphone's expanding
capabilities to design Android and iPhone apps, which they give away, to
gather personal data. In this way, environmental economist George MacKerron
at the London School of Economics recruited 40,000 volunteers through an
iPhone app he designed, called Mappiness, to measure emotions in the U.K.
At random moments every day, his iPhone app prompts the users to report their
moods, activities, and surroundings. The phone also automatically relays the
GPS coordinates of the user's location and rates nearby noise levels by using
the unit's microphone. It asks permission to photograph the locale.
By early April, volunteers had filed over two million mood reports and
Publicly, Mr. MacKerron uses their data to chart the hour-by-hour happiness
level of London and other U.K. cities on his website. By his measure, the
U.K.'s happiest time is 8 p.m. Saturday; its unhappiest day is Tuesday.
Perhaps less surprisingly, people are happiest when they are making love and
most miserable when sick in bed. The most despondent place in the U.K. is an
hour or so west of London, in a town called Slough.
On a more scholarly level, Mr. MacKerron is collecting the information to
study the relationship between moods, communities and the places people spend
time. To that end, Mr. MacKerron expects to link the information to weather
reports, online mapping systems and demographics databases.
Several marketing companies have contacted him to learn whether his cellphone
software could help them find out how people feel when they are, for
instance, near advertising billboards or listening to commercial radio, he
Mr. MacKerron said he's tempted—but has promised his users that their
personal information will be used only for scholarly research. "There is a
phenomenal amount of data we can collect with very little effort," he said.
Some university researchers have begun trolling anonymous billing records
encompassing entire countries. When mathematician Vincent Blondel studied the
location and billing data from one billion cellphone calls in Belgium, he
found himself documenting a divide that has threatened his country's ability
to govern itself.
Split by linguistic differences between a Flemish-speaking north and a
French-speaking south, voters in Belgium set a world record this year, by
being unable to agree on a formal government since holding elections last
June. Belgium's political deadlock broke a record previously held by Iraq.
The calling patterns from 600 towns revealed that the two groups almost never
talked to each other, even when they were neighbors.
This social impasse, as reflected in relationships documented by calling
records, "had an impact on the political life and the discussions about
forming a government," said Dr. Blondel at the Catholic University of Louvain
near Brussels, who led the research effort.
The MIT smartphone experiment is designed to delve as deeply as possible into
daily life. For his work, Dr. Pentland gave volunteers free Android
smartphones equipped with software that automatically logged their activities
and their proximity to other people. The participants also filed reports on
their health, weight, eating habits, opinions, purchases and other personal
information, so the researchers could match the phone data to relationships
and behavior. [analyze]
The current work builds on his earlier experiments, beginning in 2004,
conducted in an MIT dormitory that explored how relationships influence
behavior, health, eating habits and political views. Dr. Pentland and his
colleagues used smartphones equipped with research software and sensors to
track face-to-face encounters among 78 college students in a dorm during the
final three months of the 2008 presidential election.
Every six minutes, each student's phone scanned for any other phone within 10
feet, as a way to identify face-to-face meetings. Among other things, each
phone also reported its location and compiled an anonymous log of calls and
text messages every 20 minutes. All told, the researchers compiled 320,000
hours of data about the students' behavior and relationships, buttressed by
"Just by watching where you spend time, I can say a lot about the music you
like, the car you drive, your financial risk, your risk for diabetes. If you
add financial data, you get an even greater insight," said Dr. Pentland. "We
are trying to understand the molecules of behavior in this really complete
Almost a third of the students changed their political opinions during the
three months. Their changing political ideas were related to face-to-face
contact with project participants of differing views, rather than to friends
or traditional campaign advertising, the analysis showed.
"We can measure their daily exposure to political opinions," said project
scientist Anmol Madan at MIT's Media Lab. "Maybe one day, you would be able
to download a phone app to measure how much Republican or Democratic exposure
you are getting and, depending on what side you're on, give you a warning."
As a reward when the experiment was done, the students were allowed to keep
the smartphones used to monitor them.
Write to Robert Lee Hotz at sciencejournal at wsj.com
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