Objectives: The detection response task (DRT) is a method for measuring attentional effects of secondary tasks on a driver's cognitive load by measuring response times and hit rates to different types of stimuli as indirect indicators of increased cognitive load. ISO 17488 (International Organization for Standardization 2016) only provides guidelines for the technical implementation and measurement methods for the visual and tactile versions (use of visual and tactile stimuli) of the DRT method. This article presents a study with the goal of finding the most appropriate auditory stimulus for the implementation of an auditory version of the DRT method.
Methods: This article presents the results of an experiment in which responses to 7 different auditory DRT stimuli—varying in frequency—were compared while inducing users' cognitive load with a modified n-back task. The experiment was conducted in a surrogate driving environment and in a within-subject design. Response times, hit rates, and secondary task performances were observed as indicators of increased cognitive load.
Results: Significantly shorter response times were found for the white noise signal compared to single-frequency signals. However, the largest differences in response times, for trials without and with a cognitive task, were found for 4- and 8-kHz single-frequency signals. No significant differences were found for hit rates and secondary task performances between the different stimuli.
Conclusions: Consistent significant differences in response times for all tested stimuli prove that the auditory DRT variant is also sensitive to changes in cognitive load. The mean increase in response times of more than 25% for 4- and 8-kHz signals for trials with a cognitive task compared to trials without one indicates that one of these signals could be used as a potential auditory stimulus for the auditory DRT variant. 相似文献
To diagnose environmental nitrogen (N) load from food consumption and to suggest preventive measures, this study identified relationships between nitrogen load from food consumption and driving factors by examining six representative countries and regions for the period 1970–2009 as an example. The logarithmic mean Divisia index technique was used to disassemble nitrogen load growth into four driving factors: population, economic activity, food intensity of the economy, and nitrogen content of food. In all study areas, increased economic activity was the main factor driving nitrogen load increase. The positive effect of population growth was relatively small but not negligible and changes in food intensity had a decreasing effect on nitrogen load. Changes in nitrogen content of food varied between areas. Broad strategies to reduce and mitigate nitrogen loading and decouple nitrogen load from economic growth in both developed and developing countries are suggested. 相似文献