Comprehension and workload differences for VDT and paper-based reading

Computer monitors, or video display terminals (VDTs) are starting to be utilized for a wider variety of tasks including reading information. Two experiments were carried out to determine if reading information from a VDT resulted in poorer performance. The performance categories tested were reading times, comprehension of the information, and mental workload (as measured by the NASA-TLX). The first experiment found that those who read from a VDT took significantly longer than those reading from paper. To determine if this difference was due to an increased use of the resources available in working memory, a second experiment was conducted. Half of the participants in the second experiment were instructed to retain a list of letters in working memory while reading from either paper or a VDT. Those reading a paper copy of the material took longer to finish than those reading from a VDT. In contrast, a trend in the data indicated comprehension scores were lower for those reading from a VDT. Therefore the best medium for conveying information might depend on which aspect of performance is most important and on how the information is displayed in the two cases. Additional implications, applications, and future research directions also are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.