The amount of political radicalism on Latin politician campases has been "grosdy over-exaggerated" by the American press, Dr. Glaucio A.D. Soares, a prominent Brazilian sociologist, said tonight.

Students who belong to left-wing groups, he said, are more active than moderates, "but they are not more numerous. Activism grows with extremism. When it gets to voting, the leftists vote more. When it gets to meetings and demonstrations their number is distorted."

Dr. charged that the press "has reported only the vivid occurences--tho demonstrations--misrepresenting the strength of the Communist movement."

Speaking at the Latin American Association, Dr. Soares cited "the need to identify with a movement larger than the individual" and "an intolerance for ambiguity" as the primary reasons why students join Communist organizations.

But at a Social Relations Colloqulum, earlier in the day, Dr. Soares said that the growth of political radicalism in Latin America reflects in a deeper sense "a gap between social development and economic development."

Economic development alone, he asserted, "is not sufficient to explain the rise of Communism. We must compare the rate of economic development to things like the infant mortality rate, literacy and the rate of disease," indicators of social development.

"Political radicalism rises," he continued, "neither when economic development is non-existent, nor when the country is fully developed. It comes in middle states when the urban worker has not received the social benefits of progress."

In these middle states, he said, urbanization is accompanied by rising unemployment. "It is then possible to have both the growth of a middle class and a fantastic rate of unemployment. And students who see this economic dislocation are drawn to "the revolution of rising expectations."