M.I.T. announced last Friday the selection of the architectural firm, Benjamin Thompson and Associates. Inc., to design 700 units of housing which the university is planning to build on three sites for low-income and elderly families in Cambridge.

According to Walter L. Milne, assistant to the chairman of the M.I.T. Corporation, the Thompson firm was chosen because of its "demonstrated ability to adapt sensitively to its surroundings."

M.I.T. selected the firm after university officials had met with tenant groups throughout the city, and arrived at architectural guidelines with them, Milne added.

The university anticipates that federal funds will be obtained to subsidize the housing. To procure these funds, M.I.T. and its architect will file a "feasibility study' 'of housing specifications with the government under the federal housing code. Construction of the housing is now scheduled to begin in the spring of 1971.

These units are part of a housing plan by which M.I.T. will build a total of 1600 units on five sites in Cambridge. Subsidized homes for low-income and elderly families will comprise over half of these.