We hold these truths to be self-evident: That all men are created equal.

Or do we?

Law professor Edward McCaffery and economist Timor Kuran have been looking into that issue for the better part of a decade. Americans tend to proclaim their allegiance to the egalitarian ideals expressed in the Declaration of Independence, but, in private, do we believe discrimination is appropriate in certain situations, against certain types of people?

Getting an honest answer to that question isn't easy, given the social unacceptability of such views. But if there was ever a time recently when primal fear trumped political correctness in the U.S., it was in the months immediately after the terrorist attacks of Sept. 11, 2001. Kuran and McCaffery were grieving, too, but they also seized a unique opportunity — collecting raw data at a time of raw emotions.

In a survey conducted in January 2002, both on the telephone and the Internet, the researchers tested Americans' willingness to tolerate five forms of discrimination — some familiar from years of controversy, others that were new to the scene or under the radar. The results published in Political Research Quarterly revealed some intriguing inconsistencies, but, in the end, Thomas Jefferson would probably be ple ased.

"We tried to make it safe and acceptable to be discriminatory," said McCaffery, who teaches at both the University of Southern California and the California Institute of Technology. (Kuran, formerly of USC, is based at Duke University.) "We described situations where there was a reason to discriminate — a utilitarian argument, either of economic efficiency or public safety. We gave people those reasons, then asked them if they wanted to discriminate or treat people equally."

The questions were:

Should airlines be allowed to keep Arab Americans off an airplane flight?
Should employers be allowed to deny jobs to overweight people? 
Should employers be allowed to screen job applicants through genetic testing?
When considering who should be allowed to immigrate to the U.S., should well-educated foreigners be favored over the less educated?
Should police be allowed to disproportionately stop African-American motorists?

In each case, a large majority of respondents answered "no." This came as something of a surprise to McCaffery, who expected much more acceptance in keeping Arab Americans off airplanes.

"I guess you can say equality is a very deep norm in America," he said.

But the percentage of people who were willing to tolerate discrimination in certain specific instances varied considerably depending upon the specific question being asked, the respondent's gender and — most strikingly — whether they were talking to a survey taker on the phone or filling out a form on the Web.