(PhysOrg.com) -- Many Americans changed their perceptions of discrimination and racism after Barack Obama became the nation's first black president.

This belief that racial biases had softened, however, did not translate to about policies that address , according to a new University of Michigan study. In fact, opposition to affirmative action and immigration may have increased since 2008.

"When racial progress is made, and perceived, by many Americans from a variety of racial backgrounds, it may seem counterintuitive that opposition to affirmative action would increase," said Nicholas Valentino, an associate professor of and political science.

He wrote the study with Ted Brader, a research assistant professor at the U-M Center for Political Studies.

"The answer may be simple: If the playing field is perceived to be more balanced than before, then the need for policies to address inequality is lessened," Valentino said.

Perceptions of discrimination could play a factor in how some vote in next year's presidential election.

"It is possible that these perceptions could be used by both parties to mobilize their base voters," he said.

The survey involved telephone interviews before and after the 2008 presidential elections. The pre-election interviews were completed by 617 respondents and 82 percent of these completed the post-election survey. They were asked how much discrimination they thought blacks faced in America.

Prior to the election, 61 percent said there was "a lot" or "some" discrimination against blacks, but only 50 percent endorsed that view after the election. More than one in four people revised their estimate of downward immediately after the election.

Significant declines in perceived discrimination occurred in all subgroups, including blacks, whites, men, women, the rich and the poor.

Declines in perceived racism were significantly larger among conservatives, perhaps because this group opposed race-related policies to begin with.

Anxiety before the election—regardless of party affiliation or ideology—was linked to large drops in perceived discrimination as the result of Obama's victory, Valentino said.

"Anxiety may trigger a more open-minded approach to new information, and thus facilitate belief change," he said.

Other emotions such as anger, enthusiasm and sadness before the election did not seem to affect the size of the change in perceived .

"These results suggest that voters used Obama's election as a sign that things have improved for blacks even more than they previously believed. They think the playing field is more balanced," he said. "As a result, and regardless of the reality, policies designed to improve equality of opportunity such as affirmative action are seen as less necessary."

The findings appear in this month's Public Opinion Quarterly.