The Nobel Memorial Prize in Economic Sciences was awarded on Monday to two American social scientists for their work in describing the numerous relationships within a company or among companies and individuals that shape market behavior.

The prize committee cited Elinor Ostrom, 76, at Indiana University, and Oliver E. Williamson, 77, at the University of California, Berkeley, for work done over long careers. Ms. Ostrom is the first woman to receive the economics prize in the 41-year history of the award. She is a political scientist, not an economist, and in honoring her, the judges seemed to suggest that economics should be thought of as an interdisciplinary field rather than a pure science governed by mathematics.

“This award is part of the merging of the social sciences,” said Robert Shiller, a Yale University economist. “Economics has been too isolated and too stuck on the view that markets are efficient and self-regulating. It has derailed our thinking.”

The Nobel judges in Stockholm notified the winners when it was 6:30 a.m. in Bloomington, Ind., where Ms. Ostrom lives, and 3:30 a.m. in California. Mr. Williamson’s grown son, home on a visit, answered the ringing telephone and passed the call to his father, awakening him. Ms. Ostrom said she, too, was awakened by the call and afterward made herself a cup of coffee in the kitchen. Both expressed surprise that the award had come their way. They will split $1.4 million in prize money.