Research On The Perception Mechanism Of Safety Signs In Safety Management

Since the reform and opening-up, China’s industry is undergoing unprecedented great changes. But many production accidents occur along with the changes, and become a major restraining factor in the industrialization process. Safety sign is an important tool in safety management, and widely used in the social production and daily life. But the field investigation and case studies reveal that currently there are serious problems in the design and usage of safety signs, resulting in the impairment of warning effect. With poor attention effect and readability, the signs are hard to be comprehended by front-line workers, which bury hidden trouble of production accidents and labor disputes. Therefore, it is of great value to research on the existing problems such as the design and application of safety signs.The research and application of safety signs have a long history. Most researches are based on surveys and the behavioral experiments, but seldom on brain cognition and electrophysiological perspective. Safety sign design should conform to the cognitive processing and subjective experiences so as to play a better role as warning, which is precisely the research focus of Safety Production in Neuro-Industrial Engineering (Neuro-IE). Regarding previous studies, three key issues remain to be solved in order to deepen our understanding of the attention and awareness of safety signs:(1)"Is there any difference on the risk perception of various safety signs?"(2)"How do people perceive and process safety sign automatically?"(3)" Can the three components of a safety sign (i.e. picture content, background color and frame shape) affect neural perception and automatic processing? Why?" The current study focuses on these three key problems with the primary target on the neural perception and automatic processing of safety signs and completes four studies that are in relation with each other. In research I, a combination of questionnaires, interviews and the KRP (Iwcnt Related Potential) experiment are combined to study whether the hazard perception ratings has significant differences among the four types of safety signs, and whether the cognitive distinction exist in the automatic processing. Research I is a preliminary work for the latter researches, as it is not only an exploratory attempt of the research methods and experimental design, but also a base of the discussion and conclusion in following chapters.Research2studies the pictorial contents of safety signs. This research consults the first experiment’s paradigm, takes strict control over the stimuli materials, and investigates people’s automatic processing and brain cognition of different types of pictorial contents (e.g. warning signs and fake signs) by liRPs to explore the effects of pictorial contents on the design of safety signs.Based on the existing behavioral studies. Research3studies the neural perception and automatic processing of the safety sign’s background color (yellow, blue and white), which adopts a similar paradigm of Research I, and examines the way the color attributes affected people’s perception.Research4studies the perception and automatic processing of safety signs’ frame shape by the same experimental paradigm as Research3. It investigates people’s attention bias and categorization towards different frame shapes, and provides a new explanation with neuroscience perspective for the long-standing disputes over the effect of frame shapes.The current paper draws the following conclusions after the aforementioned scries of studies:(1) The hazard perception ratings have significant differences among the types of safely signs. The score of the warning sign is the highest, and then the prohibition sign, the direction sign and the instruction sign are the lowest.(2)Thc neural perception and automatic processing of different types of safety signs are significantly different. The warning signs own the best effect of risk perception, which is followed by the prohibition signs, and then the direction signs. It could be illustrated by the varied amplitudes and latencies of three ERP components (P2, N2and N4). Two stages of automatic processing are detected:the automatic attention stage and the automatic evaluation stage.(3)The subjects are very sensitive to the content of safety signs with different valences, which significantly affects the neural perceptions and automatic processing of the true and fake safety signs. It could be explained by the distinction of P2, N2, P3and SNW amplitude in the frontal area, suggesting that negative pictures are perceived and discriminated more easily and faster than neutral ones, and retrieved more cognitive resources to evoke long-term memory and associated negative experience, and finally resulted in higher level of hazard perception.(4)Significant differences exist regarding people’s neural perception and automatic processing of different background colors of safety signs. In the non-attention condition, background color of safety signs affects people’s perception processing, but is not significant to hazard evaluation of safety signs. People are sensitive to whether there is color or no color, and when there is color, yellow is advantageous over blue in the aspect of arousal and attention classification at the early perception stage. These differences are primarily reflected by the amplitudes and latencies of PI and1M1in the temporal occipital region and N2in the frontal region.(5) The attributes of frame shapes have significant influence on the neural perception and automatic processing of safety signs. Similar to the effect of color, the shape of safety sign can only facilitate the perception process, but it’s not a key factor to influence the evaluation of the hazard. Therefore, people are sensitive to whether a border exists or not during the initial stage of visual processing, and when a border exist, the shape of triangle obtains better attention than that of circle, which is mainly reflected by the differences of amplitudes and latencies of PI, N1and P2in temporal occipital region.As an exploratory study that introduces cognitive neuroscience research methodology into the study of safety signs and its designing factors, the main innovations and theoretic contributions are presented as follows:(1) The effect of different types of safety signs is studied for the first time. Previous researches are mainly focused on the design attributes and the combinations of them, and most of the studies aimed at warning signs. However, they do not look into the other types of safety signs. The current study takes four types of popular safety signs stipulated by the national standard into consideration, and investigates people’s hazard ratings of different types of safety signs by questionnaires and the neural differences by RRP experiments. The results not only extend the scope of safety sign researches, but also provide electrophysiological evidences for previous studies.(2) The influences of the design attributes of safety signs are studied from the perspective of neuroscience. Although there have been lots of work studying the design attributes and the combinations of them, few of studies retrieve evidences from the human brain. The latter three researches in this paper study the three main attributes, i.e. the pictorial contents, the color, and the frame shapes of safety signs by HRP experiments respectively, and identify the differences both in neurocognition and automatic processing. They provide new evidences for existing theories and promote the design of safety signs. By deepening the understanding of attribute design of safety signs, the present study also provides important reference for future studies on the integration of the attributes.(3) New complements for existing theoretical model are provided. The Hazard Potential Two Stage (I I PI’S) model reveals the evaluation process of the warning words by explicit rating task. Research I adopts an implicit paradigm to indicate the automatic processing and neural cognition towards safety sign pictures. Complementing the IIPTS model, new automatic stages are detected (i.e. the auto-attention stage and auto-evaluation stage).(4) New findings for the disputes of color and shape attributes’effects. Previous studies do not reach a common conclusion on the effects of the two attributes. Some researchers maintain that these two attributes enhance the warning effect, but others hold that the effects are very limited. Research3and Research4in the current study obtain new findings from neuroscience perspective. It shows that, under the passive attention condition, the background color and the frame shape have significantly positive effects on the arousal and attention classification in human brain, but not on the overall interpretation and the hazard perception at the late stage. This study provides new evidences for previous studies from a new perspective, and also provides an interdisciplinary paradigm for further studies on the disputes.This paper introduces cognitive neuroscience approach to safety signs study, the discovery of which provides theoretical guidance to the design and application of safety signs, with the aim of rendering them in line with people’s intrinsic cognition and risk assessment. We expect to enhance the role of warning and guidance in the safety management practice, and thus reduce the potential harm caused by accidents.