Space Constancy on Video Display Terminals

Work for the grant's second year progressed in four projects. The first, a report of distorted space processing in flickering fields, concerns empirical work completed. The second project extended this work to high-speed flicker, at 480 adn 960 Hz. No evidence was found that these high flicker rates have any advantages over slower rates, though some technical issues were resolved. The third project examined reading rates on CRT screens at 60 and 500 Hz. The faster rate resulted in reading that was on average 0.6 msec faster, a difference that is neither statistically reliable nor of practical consequence. Technical problems in that study were addressed in the fourth study, using more subjects and a larger and more difficult sample of reading material, with eye movement monitoring and an automatized screen refresh procedure. Initial results showed a small advantage in reading speed at the higher frequency for 4 to 6 subjects, and an overall advantage of 5 words/min at 500 Hz. Data collection is continuing in this project.