WHEN I was applying to colleges, I was drawn to Harvard's reputation of well-roundedness, its supposed strength in both the humanities, social sciences and the natural sciences. Yale was too fuzzy, MIT too techie. Only Harvard stood as the Renaissance man of schools.

But now that I am here, Harvard seems to be tipping to one side. Among the six major sciences, only physics has an increasing number of concentators. The other departments are watching their numbers of concentrators decrease significantly.

Alexander W. Astin of the University of California at Los Angeles Higher Education Research Institute is not worried. Astin feels that we need to emphasize the humanities more, so that we can tackle problems like world peace, poverty and bigotry. As he recently wrote in Science, "Our understanding of the physical universe has increased exponentially, while our understanding of the behavior of human beings and of societies has lagged far behind."

Astin is correct--since Plato's time we have not made quantum leaps in our understanding of human behavior. However this is not because of a national de-emphasis or misplaced priorities, but because human behavior may never be "understood" as the natural sciences can be.

IN fact, the leaps that have been made have not been made by humanists, but by scientists. More and more behavior is being traced to biological causes. Above all, we need doctors and researchers to work in the hospitals and laboratories, to make observations and conduct experiments, to combat AIDS, ozone, cancer and attrition.

So what if Harvard produces fewer profit-chewing physicians, some might charge, citing the classic occupation for science majors. That objection has some merit. Yet science concentrations also prepare research doctors, of whom we can never have enough. Science concentrations also make for more broadly informed politicians, lawyers and businessmen, all of whom may have to deal with scientific issues such as the atmosphere and genetics.

Statistics show steep declines in science concentrators. From 1983 to 1987 (when the total number of under-graduates remained almost constant), the number of biochemistry concentrators dropped from 300 to 212. In that same span, the number of chemistry concentrators fell from 93 to 74. And from 1985 to 1987, the number of biology concentrators went from 432 to 340. These amount to 20 to 30 percent drops in laboratory science concentrators.

Why are students turning away from the sciences? Some of the reasons might be the exaggeration of the departments' difficulty. The sciences may arguably be more taxing than the humanities and social sciences--they are more sequential, and most entail weekly labs. But popular opinion widens the gap (if there is one) between the difficulty of the sciences and non-sciences. Students may think they could not fare well in the sciences when indeed they could.

Also deterring students from the sciences is the threat of cut-throat premeds. The image of pre-meds dominating the upper portion of curves can be very intimidating.

WHAT can be done to stem the decline in science concentrators? Certain science concentrations have devised solutions which other departments can learn from.

In the Chemistry Department, the problem of pre-meds shoving down other students is somewhat alleviated by splitting organic chemistry into two tracks: pre-meds take the Chem 17-27 series, while Chem majors take Chem 20-30. More science courses ought to be cleaved in this manner.

The Chemistry Department serves as a model for flexibility. The requirements are a year of inorganic, organic, math and physics each, and a semester of labs--the last two years of college can, therefore, be filled with only three chemistry half-courses if a student wishes. These requirements are what those of the other sciences ought to look like. A student must take what is necessary for a knowledge base, but that student can also avoid all upper-level courses.

The concentrator has time to take a significant number of courses in other disciplines. The Chemistry Department also allows students to take a semester pass/fail within the concentration. This should be increased to a year in all science concentrations.

SCIENCE departments should also strive for intimacy--by this I mean an emphasis on teaching and the involvement of students in research. The Bio-chemistry Department is doing just that. It has instituted a tutorial program which requires sophomores, juniors and seniors to research with scientists in such places as the Dana-Farber Cancer Institute and the School of Public Health.

Students also have bi-weekly, one-on-one meetings with tutors. This sort of tutorial program should be carried over to the other laboratory science departments. At present, other departments have either optional tutorial programs or none at all.

Obviously the blame for the decrease in science concentrators should not fall entirely on Harvard's science departments. The allure of business and law, the fear of the socialization of medicine and other concerns have sucked students away from the sciences. Even so, Harvard's science departments ought to compensate by modifying the structure of their concentrations. The necessary changes are within their reach.