A RESOLUTION LIMITED MODEL FOR THE PREDICTION OF INFORMATION RETRIEVAL FROM EXTENDED ALPHANUMERIC MESSAGES

This paper was presented at Session 38 - Signing, Delineation and Guidance 2. A model for the prediction of information retrieval from alphanumeric messages is developed on the assumption that the physiological limit for retrieval is the capacity of the visual system to resolve detail. Since visual acuity decreases with increasing angle away from the line of sight and an alphanumeric message of any length must extend into the peripheral field of view, it follows that there must be a limit to the length of a message if the whole of it is to be resolved. Contour interaction is also taken into account in the model. Two experiments are reported, the results of which support the general principles of the model, although it appears that observers cannot retrieve information from two successive lines at a single glance, even though the words can be resolved. (TRRL)