Edward W. Karnes

Effects of Task Difficulty on Transfer Performance on Rotary Pursuit.

The effects of task difficulty on transfer performance in a perceptual-motor tracking task were investigated. Five groups of Ss (ns = 15) practiced 45 30-sec. trials with 30-sec. rests on a pursuit-rotor tracking task at 5 levels of difficulty, 30, 40, 45, 50, and 60 rpm. 48 hr. later, all Ss practiced at 45 rpm. The results showed that the extreme transfer groups (30 and 60 rpm) were significantly poorer than the central transfer groups (40, 45, and 50 rpm) on the first five trials of the second session but after 9 blocks of 5 trials, performance was similar. The roles of perceptual, motor, and strategy factors in transfer are discussed.

Perception of Risk in Automobiles: Is it Accurate?

Consumer concern with safety may be nullified because understanding of hazards associated with uses and misuses of products is often inadequate owing to lack of understanding relevant physical principles. These studies examined the publics understanding of hazards associated with automobiles. Recent safety advances have included passive restraint systems to increase the likelihood of buckling up. Such systems are usually passive/active systems, because lap belts must be manually buckled. Not buckling the lap belt may cause the system to become an injury-producing system rather than an injury-preventing system. Without lap restraint severe neck injuries and possible ejection from the vehicle can occur. Similar problems are posed by other seat belt behaviors. Surveys of general knowledge of these problems and of problems associated with the temperatures occurring in vehicles exposed to solar radiation indicated significant knowledge gaps. Suggestions are made for added warnings and informational programs to ameliorate the situation.

Adequacy of Responses to Warning Terms

Previous research has indicated that many persons have difficulty in describing the seriousness of hazards that are associated with some terms frequently used in warnings. Alternative explanations for this failure could be lack of understanding or simply inability to express their knowledge. Two studies were conducted in an effort to get more definitive information about what the general public knows about these terms. The obtained evidence suggested that many terms commonly used alone in warnings are not adequate to inform users of the extent of the hazards associated with those warnings. These results are discussed in terms of the need for completeness in warnings.

Ride-on lawnmowers warnings: Slope measurements and safety-by-separation

Various single-rider open vehicles, such as lawnmowers, are susceptible to overturning on slopes that are too steep for them. Warnings have included separation from the vehicles and avoiding slopes that are too steep. A recommended maximum slope is commonly 15 degrees. However, many individuals cannot evaluate slopes just by sight. Some mower manufacturers have warned about too steep slopes and have provided slope gauges for users to determine the slopes in natural settings. This article evaluated the usefulness of such gauges for users who might be expected to need to evaluate slopes and the efficacy of a separation procedure for avoiding injuries. It was concluded that neither of these were likely to be successful and suggestions are made for alternative approaches.

Recreational Preferences in Potential Space Crew Populations

Leisure-time preferences were surveyed in three populations which are potential sources for future space crews. A questionnaire was designed to provide rating scale measures of preferences for various spacecraft recreational equipment items, leisure-time activity categories, content within activity categories, and various kinds of snack items. The questionnaire was administered to samples from three populations: test pilots, military pilots, and aerospace engineers and scientists. Statistical analyses of the obtained data indicated that preferences for types of spacecraft leisure-time equipment were similar in the three populations. However, certain significant differences were obtained among the populations in terms of the amount of time spent in earthbound leisure-time activities. Implications for space mission off-duty concepts are discussed.

Current Issues in Warnings Selected Case Studies and Applications

Warnings and warnings-related issues continue to be an important focal point of liti-gation in the U.S. Many personal injury cases, for example, revolve around questions associated with residual hazards in products, facilities, or user environments – and the steps the manufacturer of a product, or the parties responsible for the safe operation of a facility or environment have taken to mitigate people’s exposure to those hazards. If haz-ards are not eliminated through design and/or guarding, then warnings and other types of precautionary instructions are commonly used to alert, inform, and remind people about the hazard(s) and to tell them what they should do to avoid or at least minimize injury. A significant body of published HFE / Warnings literature over the past several dec-ades has addressed a myriad of issues associated with the proper design, fabrication, and application of warnings and warning systems. However, the continuing stream of warn-ings-related cases being litigated in courts across the country, serves as an important re-minder that warnings issues are not merely abstract and theoretically interesting topics of discussion, but are rather items of concern that can have a significant, real-world impact on the conduct of our daily lives. The four HFE forensic professionals in this panel discussion session provide different but related perspectives on warnings-related applications and case study examples drawn from their respective professional practices. These discussion topics help to provide greater insights into the ways in which warnings-related research and theoretical con-structs are translated into warnings experts’ opinions in actual court cases. The following are brief summary descriptions of each discussant’s presentation.

A Case Study of Using Human Factors Analyses on Warnings

On occasion defects appear in products after some period of use. Often, the products have been distributed to many unknown individuals requiring a program to inform them of the hazardous defect. In this study a comparison is made between two warning programs one of which did not utilize good human factors principles (considering them too academic) and a second which concerned itself with the problem of notifying individuals of an unknown and potentially deadly hazard. An analysis of the human factors principles involved in such programs was performed. The human factors principles were discussed in terms of the failures of the one program to reach the target audience with information in an acceptable form. In addition, the procedures for developing an adequate warnings program are described and the techniques for testing the warnings with individuals who are akin to the target audience were presented.

Development of Warnings Resulting from Forensic Activity

One of the arguments given for pursuing the rights of injured parties through the legal system in cases involving ergonomics principles is that it encourages corporations to modify their products or the warnings given about them to produce a safer environment. Unfortunately, this does not occur as often in practice as might be hoped. This report describes a case in which support for ergonomic research was provided by a corporation that wanted to insure their warnings were adequate. The effectiveness of pictograms in aiding persons with a limited command of English was investigated. Pictograms were first tested on college students and modified in accord with the feedback obtained from them. For the final test, subjects who were taking courses in English-as-a-Second-Language and courses for adults who were learning to read were selected. They were shown a letter printed in Greek symbols with pictograph representing an individual calling to get more information about the letter, and they were asked to describe how they would go about determining what the letter said. Although not all subjects indicated that they would call the number listed, their responses indicated that they would use reasonable strategies for learning its contents. In addition to showing the feasibility of such research procedures, the experiment suggested that future research was needed on the development of symbols indicating the need “to do” certain activities.