We report on results of two experiments designed to compare subjects' ability to extract information from audio recordings of conversational telephone speech (CTS) with their ability to extract information from text transcripts of these conversations, with and without the ability to hear the audio recordings. Although progress in machine processing of CTS speech is well documented, human processing of these materials has not been as well studied. These experiments compare subject's processing time and comprehension of widely-available CTS data in audio and written formats -- one experiment involves careful reading and one involves visual scanning for information. We observed a very modest improvement using transcripts compared with the audio-only condition for the careful reading task (speed-up by a factor of 1.2) and a much more dramatic improvement using transcripts in the visual scanning task (speed-up by a factor of 2.9). The implications of the experiments are twofold: (1) we expect to see similar gains in human productivity for comparable applications outside the laboratory environment and (2) the gains can vary widely, depending on the specific tasks involved.