A highly critical report sponsored by the Education Department says that only half of college students seeking bachelor's degrees achieve them, and blames the high drop-out rate and declining student achievement on the failure of the nation's colleges to motivate their students.

The new report also chided the schools for allowing more and more undergraduates to lock themselves into narrow professional studies at the expense of broad intellectual inquiry, and said the quality of courses is "problematic. . . .In some colleges, students can earn the same number of credits for taking a course in family food management or automobile ownership as for taking a course in . . . neuropsychol- ogy."

The report notes that the problems arise at the end of a generation of dramatic change in the nation's campuses, a generation marked by a fivefold increase in college enrollment, the increasing dominance of state universities and colleges and by growing numbers of "nontraditional" students who are older, who commute to school or attend parttime.

" . . . Student learning, curricular coherence, the quality of facilities, faculty morale and academic standards no longer measure up to our expectations," the report said.

It also noted that "more and more students attend large institutions. . . . The greater the size of institutions, the more complex and bureaucratic . . . , the fewer the opportunities for . . . intellectual life and the less personal the contact between faculty and students."

The report, which will be the subject of a news conference by Education Secretary T.H. Bell on Monday, is the first of three major studies of higher education in the United States due for release this fall. The new report, "Involvement in Learning: Realizing the Potential of American Higher Education," comes 18 months after a widely publicized critique of U.S. high schools; it is designed to shift attention to the 12 million students who attend the nation's 3,300 colleges and universities.

The seven-member "study group," sponsored by the department's National Institute of Education, was headed by Kenneth P. Mortimer, a professor of higher education and public administration at The Pennsylvania State University.

The group based its findings on earlier studies and statistical data that is available from federal and private sources. It cited the decline in scores of upperclassmen on the Graduate Record Examinations.

GRE scores in 11 of its 15 subject-area exams declined between 1964 and 1982, including exams requiring the best verbal ability: history, political science, education, psychology, sociology and English literature. Scores in chemistry, geology, engineering and music also dropped. Scores increased only in biology, physics, math and economics.

The report criticized schools for failing to keep students interested or giving them any sense of the kind of intellectual achievement they are expected to attain. Freshmen in particular "are often closed out of course selections, treated impersonally and given lower priority in academic advising. . . ." Department statistics show that barely one-third of students who enroll in college receive any degree.

The authors proposed the adoption of general "proficiency" assessments as a prerequisite for graduation, suggesting that this would provide a "warranty for postsecondary credentials." Increased attention to student achievement, they said, would also provide colleges with a benchmark for evaluating their own performance.

In the same vein, they recommended that students pursue a general liberal education for two years. The suggestion comes as many schools are reinstating requirements in history, science, social science and literature that were abandoned during the upheavals of the late 1960s and early 1970s.

Currently 1,100 majors are available to undergraduates, a massive proliferation that is driven by the rise of professional programs. Nearly half of all bachelor's degrees were awarded in arts and science fields in 1971; in 1982 that proportion dropped to 36 percent, with occupational degree programs growing commensurately.

"The professional requirements collide with the schools' general requirements and the schools' requirements have to give," said John E. Trimpey, the dean of arts and sciences at the University of Tennessee at Chattanooga, who is familiar with portions of the report.

The report also advised state governments to change the system they use to distribute money. In a time of declining enrollments, the existing practice of tying school appropriations to their enrollments means "institutions will devote unwarranted energy to maintaining or increasing enrollments simply to meet costs. They will be able to exert little quality control. . . ."

While acknowledging that "one cannot eliminate formula funding . . . , " the authors urged states to set aside appropriations for public higher education for distribution on the basis of educational quality.

The report also criticized the growing number of parttime faculty members, who now comprise 41 percent of college faculties, up from 23 percent in 1966.Faculty purchasing power also has declined 20 percent in the past decade, while the proportion of college freshmen who want to become professors has declined 89 percent.