No abstract

The impact of visual display terminals on man/machine communications is explored. The necessity of developing behaviorally valid guidelines for effective user performance is discussed, with emphasis on the importance of relating the guidelines to user cognitive processes. Quantitative substantiation of these “principles” through experimentation is underscored. Finally, the extendability of the guideline approach to interactive graphics is broached.

A joint IBM-SHARE field study surveyed 229 computer users about their use of a range of information sources. On a questionnaire, each respondent described a situation where information was required to use a computer. The respondent then specified all the information sources that were consulted, judged the degree to which each met the information needs, and estimated the time required to obtain the information. With a keyword technique, responses were coded to identify user cognitive states from the situation descriptions. Three unique cognitive states identified: Learning, Solving, and Refreshing.For learning and problem solving, the best online and human sources are used at about the same rate, 70% of the time; but, humans are rated more effective at 80% versus 60% for online sources. When effective, human sources require more time, on average 24 minutes versus 9 minutes for online sources. The conclusion drawn from the study is that human sources are rated more effective than online sources because humans have four critical advantages. They are interactive speakers and listeners. They can be selective in the information presented. Humans can query at multiple levels of discourse. Humans can assess the relevance of the information presented.