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Objective: We describe a major factor in research in warnings — namely, forensics. Background: During the past three decades, much of the empirical warnings research has been published in human factors and ergonomics (HF/E) literature. A major impetus to that research has been concurrent activity by HF/E professionals participating as expert witnesses in product liability and personal injury cases in which there is a claim of failure to adequately warn about associated hazards. Method: We review how the issues in forensics can identify researchable questions. This effort has prompted important questions to be addressed that have resulted in publications. Two examples are provided: vehicle seat recline and explicitness. Results: The research has contributed to theory and model building of the processing involved. The research prompted by practical forensic issues can contribute to knowledge that is not limited in scope to particular instances, as is sometimes ascribed to applied research; it can also offer confirmatory support for theory or its modification. Conclusion: A practice-driven approach to the initiation of research can benefit not only application and practice but also theory. Application: Results in the warnings research domain can enhance safety and aid decisions in forensic contexts.

Performance in a memory-span task using eight-letter sequences was explored as a function of presentation rate (.5, .75, 1.0, 2.0, and 3.0 sec/item) and presentation mode (visual, auditory, simultaneous visual and auditory, and mixed visual and auditory). Results indicate that performance in the mixed mode was inferior to the other three modes, but the other modes did not differ from each other. As presentation rate decreased, performance improved. These results are consistent with current theories of memory and indicate that the mode in which alphanumeric information is displayed is unimportant provided the modes are not mixed.

The time required by an observer in a moving vehicle to detect controlled accelerations and decelerations by the vehicle ahead was measured for automobiles travelling on a four-lane, divided, limited-access highway. Two levels of rate of velocity change and two initial intervehicle separations were studied. Detection time increased with intervehicle separation and decreased with increasing rate of change.

The purpose of the present work was to identify some of the factors that influence effectiveness of warnings. Two laboratory experiments designed to examine behavioral effectiveness indicated that a warning placed before procedural instructions is more likely to lead to compliance than a warning that follows instructions. Two rating experiments indicated that for greatest perceived effectiveness, environmental warnings generally require a signal word plus hazard, consequence, and instruction statements. A third rating experiment suggested that informative, nonredundant statements add to a warning's perceived effectiveness. Several field demonstration studies showed that cost of compliance and salience influence behavioral effectiveness. Implications and applications to warning design are discussed.