Lab experiments have long played an important role in behavioral science, in part because they allow for carefully designed tests of theory, and in part because randomized assignment facilitates identification of causal effects. At the same time, lab experiments have traditionally suffered from numerous constraints (e.g. short duration, small-scale, unrepresentative subjects, simplistic design, etc.) that limit their external validity. In this talk I describe how the web in general—and crowdsourcing sites like Amazon's Mechanical Turk in particular—allow researchers to create "virtual labs" in which they can conduct behavioral experiments of a scale, duration, and realism that far exceed what is possible in physical labs. To illustrate, I describe some recent experiments that showcase the advantages of virtual labs, as well as some of the limitations. I then discuss how this relatively new experimental capability may unfold in the future, along with some implications for social and behavioral science.
Duncan Watts is a principal researcher at Microsoft Research NYC and an AD White Professor at Large at Cornell University. His research on social networks and collective dynamics has appeared in a wide range of journals, from Nature, Science, and Physical Review Letters to the American Journal of Sociology and Harvard Business Review. He is also the author of three books: Six Degrees: The Science of a Connected Age (W.W. Norton, 2003) and Small Worlds: The Dynamics of Networks between Order and Randomness (Princeton University Press, 1999), and most recently Everything is Obvious: Once You Know The Answer (Crown Business, 2011)