College fails to teach civic knowledge - including American history and national institutions - and has an influence on liberal leanings among students, a new study says.

The study, conducted by the conservative Intercollegiate Studies Institute, specifically cited typically liberal positions on gay marriage and school prayer.

Richard Brake, the director of ISI's Culture of Enterprise Initiative, said high schools could be partly to blame for a lack of civic knowledge but college courses should provide more concentrated study.

"You should reinforce it and go beyond it," he said. "Learning is about reinforcement."

The study tested 2,508 Americans with various education levels on 33 basic civic knowledge questions that included political literacy, American history and economics. The overall average score was 49 percent. College graduates scored at 57 percent. Respondents also answered questions about 39 social issues. The answers were compared with those from a 2006-07 study that tested more than 14,000 college freshmen and seniors on similar issues.

Mr. Brake said college students scored better on questions relating to the history of the 1900s, including those involving Susan B. Anthony and Martin Luther King Jr. He added that this is some indication of the focus of study in the classroom.

A previous study by ISI found that the average college student has taken an average of only four political science, economics and history courses, although they are considered to be parts of a general education curriculum. Mr. Brake said the study found that students who took more than four of these courses scored higher, but his main concern was of the quality of education.

He said a fragmented discipline often allows students to avoid taking basic courses that would teach civic literacy.

One portion of the study found that 58 percent of Americans ages 18 to 24 compared with 68 percent ages 45 to 64 disagreed that America corrupts otherwise good people.

Mr. Brake said he is uncertain what variables could be affecting the results.

He said it might be natural for younger people to be more skeptical, or that the older generation was educated differently.

The study shows a correlation between college education and an increase in liberal opinions on four polarizing social issues.

Of those whose education has not extended beyond high school, 24.6 percent believed gay couples should be allowed to legally marry. That compares with 39.1 percent of respondents with college degrees. More than half - 56.6 percent - of those with a high school education, compared with 39.4 percent of those with a college education, thought public school teachers should be allowed to lead prayer at public schools.

The report also found that 74.2 percent of those with a high school education agreed that the Bible is the Word of God, while 63.5 percent of those with college education agreed.

When asked whether non-Christian religions could have affected this result, Mr. Brake said the number of respondents who identified themselves as non-Christians was small.

The responses, however, were less predictable at the Ph.D level of education. Those with doctorate degrees answered more conservatively to marriage and public school prayer questions and more liberally with the Bible question and two additional questions.

Mr. Brake said public opinion is complex.

"There are all sorts of things that contribute to why you think a certain way," he said.

An additional finding of the study concluded that civic knowledge broadens a person's frame of mind.

It said respondents who scored higher on the civic literacy test were more likely to agree that prosperity depends on entrepreneurs but less likely to agree that free markets bring about full employment.

Mr. Brake said the study shows only that there is a lack of civic education at the college level, and that it does not define right or wrong public opinion.

"A lot of this has to do with making more informed consumers," he said. "That's the whole purpose of this initiative."