Evaluated were the role and importance of request-receiver feedback in an information system. Participants were 50 university biological scientists who agreed to place requests for information by telephone with a specially established clearinghouse. One type of receiver was a scientist holding a Ph.D. in biochemistry, with over 20 years biological research experience. He interacted with the requester, providing "technical" and "conventional" feedback. The other receiver was represented by a tape-recorder which recorded the call but was unable to provide feedback. A schedule was provided to participants each week indicating the type of answering service which would be available. The requesting behavior of participants with the two types of request-receivers was analyzed. Results indicated that (1) three out of four scientists made exclusive use of the scientist receiver, while one in five used the tape-receiver exclusively, (2) the main objection raised against the tape-receiver was lack of feedback, (3) the tape method was generally used to place brief well-articulated requests, or less difficult requests, and (4) aid in structuring requests as well as mere confirmation responses seemed to be valuable services. A complete description of the operation is given, and the need for request-receiver feedback capability in an information clearinghouse is discussed. (DS)