Nine exploratory studies and five formal experiments were conducted to determine 1 whether stress decrements occur in a complex display monitoring situation 2 if so, what variables contribute most to these decrements and 3 what conditions--particularly display conditions-- may be introduced to reduce such decrements. Variables studied include stimulus density signal frequency, kind, and predictability irrelevant signal characteristics display format duration of monitoring and response requirements. The major findings suggested that serious stress decrements do occur, but these are not simple monotonic functions over time. Decrements are most severe under conditions of high display density and low signal frequency particularly when predictability of signal occurrence is low and irrelevant information is present. Performance does not seem to deteriorate over weeks or months of daily monitoring sessions. Display formats in which classes of information are separated spatially or in which some spatial compression is introduced seem to reduce decrements and enhance overall performance. Implications of these and other more tentative findings are discussed relative to the problem of display design and future research.