Validation of auditory detection response task method for assessing the attentional effects of cognitive load

Objectives: There are 3 standardized versions of the Detection Response Task (DRT), 2 using visual stimuli (remote DRT and head-mounted DRT) and one using tactile stimuli. In this article, we present a study that proposes and validates a type of auditory signal to be used as DRT stimulus and evaluate the proposed auditory version of this method by comparing it with the standardized visual and tactile version.

Methods: This was a within-subject design study performed in a driving simulator with 24 participants. Each participant performed 8 2-min-long driving sessions in which they had to perform 3 different tasks: driving, answering to DRT stimuli, and performing a cognitive task (n-back task). Presence of additional cognitive load and type of DRT stimuli were defined as independent variables. DRT response times and hit rates, n-back task performance, and pupil size were observed as dependent variables.

Results: Significant changes in pupil size for trials with a cognitive task compared to trials without showed that cognitive load was induced properly. Each DRT version showed a significant increase in response times and a decrease in hit rates for trials with a secondary cognitive task compared to trials without. Similar and significantly better results in differences in response times and hit rates were obtained for the auditory and tactile version compared to the visual version. There were no significant differences in performance rate between the trials without DRT stimuli compared to trials with and among the trials with different DRT stimuli modalities.

Conclusions: The results from this study show that the auditory DRT version, using the signal implementation suggested in this article, is sensitive to the effects of cognitive load on driver's attention and is significantly better than the remote visual and tactile version for auditory–vocal cognitive (n-back) secondary tasks.     

论灾害医学及灾后的医疗卫生保障

文中对灾害医学的诞生和发展,灾害医学的特点以及灾害医学的任务进行了论述,并对军队在灾后救援中的作用作出客观的评价。     

Development of statistical models for predicting muscle and mental activities during repetitive precision tasks

This study was conducted to develop muscle and mental activities on repetitive precision tasks. A laboratory experiment was used to address the objectives. Surface electromyography was used to measure muscle activities from eight upper limb muscles, while electroencephalography recorded mental activities from six channels. Fourteen university students participated in the study. The results show that muscle and mental activities increase for all tasks, indicating the occurrence of muscle and mental fatigue. A linear relationship between muscle activity, mental activity and time was found while subjects were performing the task. Thus, models were developed using those variables. The models were found valid after validation using other students’ and workers’ data. Findings from this study can contribute as a reference for future studies investigating muscle and mental activity and can be applied in industry as guidelines to manage muscle and mental fatigue, especially to manage job schedules and rotation.     

Task type as a moderator of positive/negative feedback effects on motivation and performance: A regulatory focus perspective

Applying Higgins' regulatory focus theory, we hypothesized that the effect of positive/negative feedback on motivation and performance is moderated by task type, which is argued to be an antecedent to situational regulatory focus (promotion or prevention). Thus, first we demonstrated that some tasks (e.g., tasks requiring creativity) are perceived as promotion tasks, whereas others (e.g., those requiring vigilance and attention to detail) are perceived as prevention tasks. Second, as expected, our tests in two studies of the moderation hypothesis showed that positive feedback increased self‐reported motivation (meta‐analysis across samples: N = 315, d = 0.43) and actual performance (N = 55, d = 0.67) among people working on promotion tasks, relative to negative feedback. Positive feedback, however, decreased motivation (N = 318, d = ?0.33) and performance (N = 55, d = ?0.37) among individuals working on prevention tasks, relative to negative feedback. These findings suggest that (a) performance of different tasks can affect regulatory focus and (b) variability in positive/negative feedback effects can be partially explained by regulatory focus and task type. Copyright © 2010 John Wiley & Sons, Ltd.     

行为形成因子分析方法评述

为全面了解人因可靠性分析(HRA)中行为形成因子(PSF),对现有的PSF分析方法进行评述。分析情景环境的各种称谓,指出PSF是目前认可程度最高的一种,并规范PSF的定义及其内涵。分2种类型评述当前PSF的分类方法:基于影响机理分类和系统化分类。评述在HRA中PSF的选择和使用情况,针对不同的问题给出选择和使用PSF的建议。分别从定性评价和定量评价2个方面对PSF的评价方法进行评述。结果表明,PSF分析方法仍处于发展之中,需要在后续工作中不断改进。     

Prediction of Musculoskeletal Discomfort in a Pick and Place Task (A pilot study)

A pilot study was conducted regarding the effects of working posture, handling frequency, and task duration on musculoskeletal discomfort. Participants rated their discomfort perceived while performing a repetitive task at 8 different combinations of manipulations. Pauses between the work periods lasted 15 min. Discomfort was rated according to Borg’s category-ratio scale CR-10 and postures were recorded by an optoelectronic movement registration system. From linear multiple regression analysis equations for predicting discomfort at various body regions were obtained. Coefficients of determination especially point to trunk inclination and handling frequency as major determinants of musculoskeletal discomfort.     

A Study on the Combined Effect of Noise and Vibration on Operators’ Performance of a Readability Task in a Mobile Driving Environment

This paper presents a study in which the main objective was to investigate the combined effect of noise and vibration on the performance of a readability task in a mobile driving environment. Subjects performed a readability task on a laptop computer in a sitting posture with their backs supported with a backrest under varying levels of noise and vibration. The data in terms of the mean number of characters read per minute were collected and statistically analyzed. Results showed that the individual effect of noise, vibration, and the operators’ gender as well as the interaction between gender and noise, and gender and vibration were statistically significant. However, the combined effect of noise and vibration was not found to be statistically significant. Results also indicated that gender was statistically significant at all levels of noise as well as vibration, and noise and vibration were statistically significant at both levels of gender.     

建材产业发展循环经济的任务目标与措施

从多方面论述了建材产业发展循环经济的任务、目标、技术路线及措施。指出在循环经济之业链中,建材产业将成为资源减量化、再利用、再循环途径最多和潜力最大的产业之一,建材产业发展循环经济,既可实现自身的可持续发展,又可促进和带动其他行业循环经济的发展。     

Assessing the number of users who are excluded by domestic heating controls

Space heating accounts for almost 60% of the energy delivered to housing which in turn accounts for nearly 27% of the total UK's carbon emissions. This study was conducted to investigate the influence of heating control design on the degree of ‘user exclusion’. This was calculated using the Design Exclusion Calculator, developed by the Engineering Design Centre at the University of Cambridge. To elucidate the capability requirements of the system, a detailed hierarchical task analysis was produced, due to the complexity of the overall task. The Exclusion Calculation found that the current design placed excessive demands upon the capabilities of at least 9.5% of the UK population over 16 years old, particularly in terms of ‘vision’, ‘thinking’ and ‘dexterity’ requirements. This increased to 20.7% for users over 60 years old. The method does not account for the level of numeracy and literacy and so the true exclusion may be higher. Usability testing was conducted to help validate the results which indicated that 66% of users at a low-carbon housing development could not programme their controls as desired. Therefore, more detailed analysis of the cognitive demands placed upon the users is required to understand where problems within the programming process occur. Further research focusing on this cognitive interaction will work towards a solution that may allow users to behave easily in a more sustainable manner.     

四川省环境科技研究方向与任务

本文通过对四川省环境特点的分析与环境科技工作的回顾,提出四川省环境科技研究方向与任务的建议,与环境科技管理及研究人员共同研讨。