Social Physics I

Pulling heavily from the introduction to Social Physics.

Frankly, skimming below for emphasized words and block quotes will get you the gist, but I like to shore up with quotes directly from the source. And sometimes, I like to bloviate.


If I were preparing to create a PBS documentary of this book, I’d probably start with a campy scene with a telescope or microscope, and I’d talk about the interplay between the development of technologies that extend the senses, and new concepts and sciences, notations and theories, that the new observations support. The technologies that enable “Big Data”, I might argue, are the new telescopes.

“Our ways of understanding and managing the world were forged in a statelier, less connected time. Our current conception of society was born in the late 1700s during the Enlightenment and crystallized into its current form during the first half of the twentieth century. […] When we think of how to manage our society, we speak of “markets” and “political classes,” abstractions that events move slowly, so everyone has pretty much the same information and so people have time to act rationally.”

These assumptions are outdated. Groups can form and dissolve much faster thanks to technology and globalization. We need to develop more useful concepts for the new world- “we can no longer think of ourselves as only individuals reaching carefully considered decisions; we must include the dynamic social effects that influence our individual decisions and drive economic bubbles, political revolutions, and the internet economy.”

The goal of this book is to develop a social physics that extends economic and political thinking by including not only competitive forces but also exchanges of ideas, information, social pressure, and social status in order to more fully explain human behavior. To accomplish this we will have to explain not only how social interactions affect individual goals and decisions but, more importantly, how these social effects produce Adam Smith’s otherwise mysterious invisible hand. Only once we understand how social interactions work together with competitive forces can we hope to ensure stability and fairness in our hyperconnected, networked society.


II. What is Social Physics?

Just as the goal of traditional physics is to understand how the flow of energy translates into changes in motion, social physics seeks to understand how the flow of ideas and information translates into changes in behavior.

“Social physics is a quantitative social science that describes reliable, mathematical connections between information and idea flow on the one hand and people’s behavior on the other. Social physics helps us understand how ideas flow from person to person through the mechanism of social learning and how this flow of ideas ends up shaping the norms, productivity, and creative output of our companies, cities, and societies. It enables us to predict the productivity of small groups, of departments within companies, and even of entire cities. It also helps us tune communication networks so that we can reliably make better decisions and become more productive.”

Example: Pentland and his army of grad students were allowed by a broker to “try a social physics approach” to see if financial day traders could improve their gains. “By analyzing the millions of detailed messages among traders on a social network, we discovered that the effects of social influence within the network were too strong, causing the phenomenon of herding, in which the traders overreacted to each other, and so all tended to adopt the same trading strategy.” Pentland’s team determined that the best approach was to slow the spread of new strategies. “When we implemented these changes, it doubled the average return on investment, leaving the standard economic approaches in the dust.” [More information on this case is promised later in the book].

Pentland quickly addresses the fact that “social physics” was originally used in the early 19th century, when “society was conceptualized as a vast machine”. This is a view that we all (for some definitions of “all”) safely reject. We should also be careful not to go too far the other way, and to only describe social behavior in a way that isn’t terribly causal or useful beyond personal appreciation. He credits David Marr for progress in the form of a “computational theory of behavior: a mathematical explanation of why society reacts as it does and how these reactions may (or may not) solve human problems.” This theory “focuses on the human generative process, [and] is what is required to build better social systems. Such a theory could tie together mechanisms of social interactions with our newly acquired massive amounts of behavior data in order to engineer better social systems.” This book means to present the early bit of this view.

Real world examples promised:

  • financial decision making (including bubbles)
  • “tipping point”-style cascades of behavior change
  • recruiting millions of people to help in a search, to save energy, to vote, to shape political views, purchasing behavior, health choices.

The ultimate test will be pragmatic: Can the computational theory of behavior shape outcomes? It’s being deployed in various environments, so I suppose we’ll see.

Pentland also hopes to introduce sets of concepts to better describe our world.

Big Data is “the engine that drives social physics.” Pentland calls the system for analyzing patterns in the torrents of data all around us as “reality mining” (a phrase Pentland has coined previously, I believe). Events that seem unrelated or even random “acts of God” can sometimes be glimpses through reality mining.

Most current social science is based on either analysis of laboratory phenomena or on surveys- that is, on descriptions of averages or stereotypes. These approaches don’t account for the complexity of real life, when all of our mental quirks operate at the same time. [They also miss the critical point that the details, the micropatterns, the exchange of not just goods and money but also “information, ideas, or just gossip” matter]. Big data give us a chance to view society in all its complexity, through the millions of networks of person-to-person exchanges.

“The scientific method used in social physics is different from that used in most social sciences, because it principally relies on ‘living laboratories’.” By this Pentland means cordoning off an area and then recording every interaction and behavior possible for a sustained period of time. Pentland and his team are essentially running diagnostic tests on whole social organisms (groups, companies, communities). It’s also important to note that Pentland has “developed legal and software tools to protect the rights and privacy of the people in these ‘labs’ to insure that they are fully informed about what is happening to their data and that they maintain the right to opt-out at any time”. [Details on this are available online and, apparently, later in the book.]

We are running into a future where more and more variables are being recorded, continuously, more-or-less from now on.

“Anonymized data, visualizations, code, documentation, and papers” can be found here.

The two most important concepts in social physics are Idea Flow and Social Learning.

  • Idea Flow exists within social networks, and can be “separated into exploration (finding new ideas/strategies) and engagement (getting everyone to coordinate their behavior)”.
  • Social learning is “how new ideas become habits”. Learning can be “accelerated and shaped by social pressure.”

Pentland ends his introduction by talking about social implications of Social Physics. He is excited for the emergence of the field, clearly, but he is also concerned about data abuse and has suggestions for a “New Deal on data”. He is interested in providing real empiricism for the thin veneer of social science behind policy today.

More soon.


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