Stress Effects and the Optimum Format of a Scrolling Seven-Line VDT Text Window

Several aerospace applications have been identified for small text windows incorporated into existing computer VDT display screens. These text windows will provide system designers and software engineers with a means of providing realtime interactive plain English instructions on the same VDT screen as graphic or numerical data to which the instructions pertain. In aerospace applications, the screen space available is expected to be very small. For purposes of this report, on screen windows are presumed to allow for no more than seven lines of text. This report evaluated the effect of time pressure or stress on a key formatting decision which designers must now make concerning these text windows. The NASA Human Factors Laboratory (in conjunction with Lockheed) has run an experiment to determine the most appropriate location (within a seven-line text window) for the current operative instruction (i.e., the current open check-item). This experiment presents a simplified version of a proposed Shuttle/Space Station VDT screen text window with the current operative line-item at the top, middle, or bottom of the inserted text window. This student engineering report centers around a modification to the original NASA/Lockheed experiment. An additional factor (three levels of time stress) has been applied to the experiment. Appropriate background material is included (in the introduction of this report) to support the student's contention that time stress may have a significant interaction effect on optimal location of the current operative line-item within a seven-line text window. The data from this new modified experiment does, in fact, partially support this contention.