Lila F. Laux

Information processing components of substitution test performance

Abstract Although substitution tests have been included in tests of intelligence for years, the underlying abilities they measure have still not been clearly determined. This study used componential analysis to investigate the information-processing components underlying substitution test performance. The bases of sex and age differences were also of interest. One hundred subjects from each of three age groups (9–11, 18–25, and 60–89 years) were tested. The componential analysis found that substitution tests measure perceptual speed and, to a lesser extent, memory ability and writing speed. The component “Stimulus Orientation, Response Initiation, and Execution” was related to substitution test performance in the sample of children and the sample of older adults but not in the sample of younger adults. Verbal ability was not significantly related to substitution test performance in the two younger samples but was strongly related to substitution performance in the oldest sample. Although females outperformed males on the Symbol Digit Test, males did as well as females on the computerized tasks. Apparently, sex differences in substitution test performance cannot be explained by the components of the test measured here.

Effects of Explicitness in Conveying Severity Information in Product Warnings

Manufacturers typically provide consumers with a warning message on the label of potentially hazardous products in order to encourage their safe use. Warnings often vary in explicitness and severity, where explicitness refers to the specificity of the stated injury consequences and severity refers to the harshness of the consequences. This study examined the nature of the relationship between explicitness and severity and explored changes in peoples perceptions of four common consumer products as a result of exposure to warnings that varied on these two dimensions. The results show that explicitness and severity are related. The results also demonstrated that exposure to explicit warnings produced an increase in rated severity of injury and intent to act cautiously with a product. Overall this study suggests that, unless they are explicit, warnings on common consumer products may not change perceptions and subsequent intentions to act cautiously.

Recognizability and Effectiveness of Warning Symbols and Pictorials

In this study we sought to determine the relative effectiveness of pictograms for a group of 139 subjects ranging in age from 17 to 83. We gave a pictogram identification task for 16 pictograms from the Westinghouse Product Safety Label Handbook (1981) to subjects. Pictogram identification ranged from 100% to completely unrecognizable. Generally, pictorials which depicted simple, clearly identifiable hazards or protective equipment were more identifiable than symbols. Pictograms which showed the injury occurring to a hand rather than the entire human figure were also more recognizable. Finally, to explore more than simple pictograms identification, we presented subjects with three pictograms: We asked half of the subjects to list all of the ways they could be hurt, injured or killed as well as any precautions they would take while using a product displaying one of the pictograms. The other half of the subjects endorsed precautions that they would observe on a checklist of possible precautions. In general, subjects were able to name at least one of the hazards associated with each graphic, but they generally did not name all of the hazards for a given pictogram. Sex and age effects are commented on in the paper.

The Role of Human Engineering in the Design of the Orion Spacecraft

The panel will discuss NASAs Crew Exploration Vehicle, Orion, which is being designed to take four humans back to the moon, and lay the groundwork for future manned missions to Mars. Given that the last design work for such a vehicle was performed over 30 years ago, a lot has changed. Since the contract was only recently awarded (2007), there is much work to be done: finalize requirements, mature the technology, design the systems and modules, produce the hardware and software, test the systems, and prepare for first flight operations planned for 2014. The panel, consisting of customer and contractor human engineering professionals, as well as an astronaut who is actively participating in the design process, will discuss current design issues, human factors approaches that are being applied, and current technical and cultural challenges. Audience insights and recommendations for addressing these challenges will form the interactive portion of the panel session.

Driver Locus of Control: Age and Sex Differences in Predicting Driving Performance

Increasing age is associated with an increase in the rate (per mile driven) at which drivers have driving accidents, particularly fatal accidents. In the oldest age groups, men in particular are at risk. If beliefs about the controllability of accidents are reflected in differences in safety-related behaviors, and if increasing age is associated with more external control beliefs about accidents, this might be reflected in changes in safety and driving behavior which could result in increased accident rates. We assessed Driver Locus of Control and found mixed support for that hypothesis, depending on sex and control beliefs addressed, in a group of drivers aged 40–92.

Individual Differences in Visual Perceptual Processing: Attention, Intelligence, and Display Characteristics

Researchers have found little evidence that the ability to identify briefly presented simple stimuli (single letters, symbols) is related to intelligence in normal populations although performance on visual processing tasks which impose a greater attentional load (words, phrases, sentences) has been found to correlate with scores on reading tests. This study assessed the correlation between performance on seven visual processing tasks and intelligence as measured by the Ravens and the Nelson-Denny Reading Test. Intelligence correlated with tasks that required the identification of a confusable target, tasks in which the target was defined by a conjunction of features, and tasks in which the target was defined by its location. Intelligence did not correlate with the ability to identify single targets or targets defined by a single non-confusable feature. Other studies have shown that when attentional load is increased by increasing the number of characters in the display, performance is affected differently for confusable and conjunction targets. Increasing the attentional load reduces the number of hits in the confusable condition and increases the number of false alarms in the conjunction condition. In this study these two measures correlated with intelligence but not with each other, meaning that they assess different aspects of visual perceptual processing efficiency. We conclude that when it is critical to correctly identify targets and to avoid false alarms when monitoring complex displays, targets should not be confusable and should be defined by a single feature. When this is not possible, it is important to select operators who are more efficient at processing confusable and conjunction-defined stimuli.

Micro- and Macroethical Aspects of Caring for the Aged

Physicians face several different ethical microquestions in treating patients of all ages. Ethical questions about withdrawal of life support, informed consent, and extent of therapeutic intervention are encountered more frequently in the treatment of older patients. Moral pluralism and rapid technological advancement complicate the task of developing an acceptable set of ethical guidelines for addressing these questions. The formulation of comprehensive ethical guidelines for medical practice requires a wide-ranging discussion by people with backgrounds other than medicine.