NOTE ON INFORMATION-TRANSFER RATES IN HUMAN-COMMUNICATION

Information-transfer (IT) rates in bits/sec were estimated for a varie ty of methods of human communication and modalities of reception. Usin g previously published data, a range of communication rates for which transmission is highly accurate was established for each method and mo dality. These communication rates were converted into a normalized uni t of transmission (words/sec). The normalized units were then converte d into estimates of IT rate (bits/sec) using Shannon's (1951) calculat ions of the information content of a single letter of the alphabet. Ma ximal estimates of IT rates of roughly 40 to 60 bits/sec are observed for speech (through audition) and for reading and sign language (throu gh vision). Maximal rates roughly 50 percent lower are obtained for re ading through the tactual sense. Estimates of IT rates for motor outpu t tasks are also considered. A close correspondence is generally obser ved between IT rates for receiving a given display and IT rates for th e motor output task required for producing the display. These results have implications for the design of synthetic-environment systems and the displays and controls to be used in these systems, by providing ex amples of communication rates that have been achieved by humans in the area of language communication.