Six Core classes rank among the spring's 10 largest courses, up from four last year, according to figures released yesterday from the registrar's office.

As the dust from shopping period settled, Social Analysis 10, "Principles of Economics," retained its traditional first-place position, with 1016 students, followed by History 1628. "The American Century: 1945 to the Present" in second place and Literature and Arts B-16, "Abstraction in Modern Art" in third.

Last spring's runner-up, Literature and Arts C-14, "The Concept of the Hero in Hellenic Civilization," suffered a large drop in enrollment and is no longer among the top 15.

History 1628 is popular because it covers "a period that people never got to in high school history," Alan Brinkley, Dunwalke Associate Professor of American History, hypothesized yesterday. He called his course's high rank "a dubious honor."

The high enrollment for fourth-place winner History 1958, "Popular Culture in the Modern Context," surprised Pforzheimer University Professor Oscar Handlin. "I didn't know if there would be four people, 40, or 400," Handlin said yesterday.

The course requires students to watch a television series throughout the semester "They do that anyway," Handlin said, but added that he does not believe the high enrollment is related to the relatively light workload.

Handlin cited a study by the Office of Instructional Research last spring, which found that students' grades in History 1958 last year correlated "just about on the nose" with their grades in other courses.

Five of the Core courses in the top 10 were new to the list. Literature and the Arts B-16; Literature and the Arts C-31. "Literature of the Outsider in America," Literature and Arts A-12, "Great Novels of 19th and Early 20th Centuries", Historical Study A-12, "International Conflicts in the Modern World"; and Historical Study B-5, "The World of the Early Christians."

Students flocked to Lit and Arts B-16 because "everyone wants to know what to say about modern art," Diane W Upright, associate professor of Fine Arts, and instructor of the course, said yesterday.

Some students probably took the course, "Literature of the Outsider in America," because the readings are "directly pertinent to their own experience," said Andrew H. Delbanco '73, assistant professor of English and American Literature.

Disappointment

The high enrollment in Historical Study B-5, "The World of the Early Christians," disappointed Zeph Stewart, Mellon Professor of Greek and Latin, who said he prefers smaller classes in which one can "get closer with the people you're teaching." He speculated that limited offerings in the Historical Study department caused the large enrollment in his course.

Core courses have been steadily overtaking the spring top-10 list for the past three years. Six ranked this year, and four in 1982 and 1981. Two made the list in 1980, two years after the first Core courses were instituted.

Edward T. Wilcox, director of General Education and the Core, said yesterday that high Core enrollments cause "very serious resource problems and sectioning problems." Wilcox added that he has "no idea" whether he can find resources to accommodate all students in the Core.

Doctors

Two science courses maintained their high rankings. In spite of its high enrollment, Chemistry 20b, "Organic Chemistry," is "not popular," according to William V. Doering, Mallinckrodt Professor of Chemistry. Rather, it is simply "an inescapable requirement for medical school."

The enrollment in Biology 7a, "Introductory Biology," has declined in the past three years, although the course remains one of the most attended at Harvard. The instructors, J. Woodland Hastings, professor of Biology, and Lawrence Bogorad, Cabot Professor of Biology, both speculated that the number of people interested in medical school is going down.

Otto Eckstein, Warburg Professor of Economics, yesterday offered three reasons for the perennial popularity of his course, Social Analysis 10.

"Harvard undergraduates feel their opportunity for jobs is enhanced by studying economics," he said. He also noted that the course is "carefully polished," with work books, at least four types of sections, and "an outstanding staff of young teachers," and that public interest in economics is currently at "a fever pitch."