That prompted demands from lawmakers that the unclassified version of the study be publicly released.
An earlier version of the study was presented at a conference last year.
He also said the academy planned to publish a version of the study, which it would edit.
That is down from 98 percent in 2009, in a previous version of the study.
The 2012 version of the study suggests they have an almost bottomless appetite for media.
In another version of the study, Bloom and his colleagues offered a choice between two tokens all around, or one for the subject and none for her counterpart.
(A revised version of the study -- "Why Is There So Little Money in U.S. Politics?" -- will be published in The Journal of Economic Perspectives, and it is now available online at econ-www.mit.edu /faculty/snyder).
Dr. Colglazier said the academy had been willing to omit from the published version of the study secret data or passages that could be harmful to national security, but the government had not identified such material.
Broockman and Kalla are now working with Fleischer to give the story a happier ending: when we spoke, Fleischer said that the three of them were in the process of running a new version of the study.
Ms. Bernard served on a board of consultants that helped design and oversee the study, but she withdrew her support for the published version of the study, saying its conclusions were not supported by the underlying data.
"At first I thought it was just the sodium, but it went on," said Dr. Roberts, who is planning a more expansive version of the study.
