One such paper, by Dirk Brockmann, a professor of physics at Northwestern University, tracks paper currency as a surrogate for the movement of people. Using data from the wheresgeorge.com Web site, where volunteers track the location and flow of more than 129 million bills of various denominations, Dr. Brockmann found similar routines of movement that also resemble those of animal foraging.

The cellphone researchers pointed out that the new paper moved the field forward significantly because people hold on to their phones, and so the movement of individuals is more closely tracked than it can be with paper currency that is passed from person to person. As the researchers put it in the paper, “Dollar bills diffuse, but humans do not.”

Both lines of research, however, suggested that people did not really move around much.

Dr. Brockmann, who was a reviewer on the new paper, said he first approached it with some trepidation  “I said, ‘Oooh, I hope this does not completely falsify what we found.’ ” Instead, he said, “I was very happy to see that it was consistent with what we found, even though the patterns of travel were obtained by very different sets of data.”

The use of cellphones to track people, even anonymously, has implications for privacy that make this “a troubling study,” said Marc Rotenberg, a founder of the Electronic Privacy Information Center in Washington. The study, Mr. Rotenberg said, “raises questions about the protection of privacy in physical spaces, when devices make possible the capture of locational data.”

There are serious ethical issues as well, said Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania. While researchers are generally free to observe people in public places without getting permission from them or review from institutional ethics boards, Mr. Caplan said, “your cellphone is not something I would consider a public entity.”