地铁声环境对X光安检员工作绩效的影响研究

张文瑾

摘  要

地铁行李安全检查是保障旅客人身安全的重要措施，受到政府和社会的高度重视。我国的行李安全检查是采用X射线安检设备在繁杂的环境中进行的，地铁安检员长期暴露于高强度的噪声环境中会分散注意力、影响情绪唤醒程度，进而可能导致X光安检绩效降低，甚至可能引起地铁安全事件的发生。基于此，本课题通过实验研究探索地铁站厅噪声强度对X光安检人员心理状态及认知表现的影响，对地铁运营安全具有重要的意义。

本文设计了两种基于多目标安检识别认知测试的实验方案，并同步记录受试者在实验中的脑电及认知表现数据。其次，采用带通滤波和独立分析进行脑电预处理，使用基于周期图法的频域分析提取0.5-50 Hz之间表征注意力及情绪唤醒水平的频谱特征。最后，分别从总体及时间维度上分析声压级对注意力、唤醒水平和认知表现的影响特性，并进一步探讨认知表现与注意力、唤醒水平的关系。

实验结果显示，注意力与测试成绩之间呈线性正相关关系，当声压级为66.3 dBA时有利于集中安检人员注意力，降低违禁品漏检率，而声压级为76.7 dBA时会分散注意力，使安检人员反应迟钝。而唤醒水平与认知表现无相关性，当任务简单时声压级为87.7 dBA会有利于情绪唤醒，任务复杂时声压级为76.7 dBA更有利于情绪唤醒，而声压级为96.1 dBA时均不利于情绪唤醒。还发现，工作时间及任务复杂度会影响实验者对声压级的敏感度，从而影响注意力、唤醒及认知表现的变化情况。同时，本文验证了直接借助分心假说解释噪声对工作表现的影响结果是具有科学性的，而同样的实验结果也验证了直接利用唤醒理论解释实验认知结果不具有可靠性。

结合实地调研结果表明，合理安排工作时间及科学降噪可最大化提高地铁安检人员的工作绩效。并且，本文的研究不仅可用于X光安检人员工作绩效管理，还可以用于改善人体舒适度。

关键词：地铁声环境；X光安检；绩效；认知表现；情绪唤醒

Abstract

Baggage security screening of the subway is an important measurement to ensure the personal safety of passengers, and it is highly valued by the government and society. In China, baggage security-checking staff is carried out using X-ray equipment in complicated environment. Security screeners of the subway who have been exposed to high-intensity noise for a long time will distract and affect the level of emotional arousal, which may reduce the performance of X-ray security-checking staff and may even cause subway safety incidents. Based on this, systematic laboratory experiments were carried out to clarify the adverse effects of noise intensity on security screeners’ psychological state and cognitive performance, which is of great significance to the safety of subway operations.

The paper designs an experimental scheme based on multi-objective visual search task, which has two dimensions: simple and complex. And simultaneously record the subject's EEG signals and cognitive performance data during the experiment. Secondly, band-pass filter and independent component correlation algorithm are used for the preprocess of EEG signals. Frequency domain analysis based on the periodic graph method is used to extract spectral features between 0.5-50 Hz in order to assess attention and emotional arousal levels. Finally, the article analyzes the impact characteristics of sound pressure level on attention, arousal level and cognitive performance from the overall and time dimensions, and further explore the relationship between cognitive performance and attention and arousal level.

The results indicate that there is a linear positive correlation between attention and test scores. When the sound pressure level is 66.3 dBA, it is conducive to concentration and reduce the false detection rate of security screeners, but when the sound pressure level is 76.7 dBA, the security screeners will be distracted and unresponsive. However, arousal level does not affect cognitive performance. When the task is simple, the sound pressure level of 87.7 dBA will be conducive to emotional arousal, but when the task is complex, the sound pressure level of 76.7 dBA is more conducive to emotional arousal. However, in tasks of different complexity, when the sound pressure level is 96.1 dBA, it is not conducive to emotional arousal. The experiment proves that it is scientific to use the distraction theory to explain the experimental cognitive results directly, but it is not reliable to use the arousal theory to explain the experimental cognitive results directly. It was also found that working time and task complexity will affect the subject's sensitivity to the sound pressure level, which in turn affects changes in attention, arousal and cognitive performance.

Combined with field research, the results show that arranging reasonable working hours and scientific reduction of the noise in the working environment can maximize work performance of security screeners. Moreover, this research is conducive to the management of performance of X-ray security screeners, but also improves human comfort.

Keywords: Acoustic Environment of Subway Station hall; X-Ray Screening; Performance; Emotional arousal; Cognitive Performance