Impact of Construction Workers’ Hazard Identification Skills on Their Visual Attention

Abstract

Eye-movement metrics have been shown to correlate with attention and, therefore, represent a means of identifying and analyzing an individual's cognitive processes. Human errors-such as failure to identify a hazard-are often attributed to a worker's lack of attention. Piecemeal attempts have been made to investigate the potential of harnessing eye movements as predictors of human error (e.g., failure to identify a hazard) in the construction industry, although more attempts have investigated human error via subjective measurements. To address this knowledge gap, the present study harnessed eye-tracking technology to evaluate the impacts of workers' hazard-identification skills on their attentional distributions and visual search strategies. To achieve this objective, an experiment was designed in which the eye movements of 31 construction workers were tracked while they searched for hazards in 35 randomly ordered construction scenario images. Workers were then divided into three groups on the basis of their hazard identification performance. Three fixation-related metrics-fixation count, dwell-time percentage, and run count-were analyzed during the eye-tracking experiment for each group (low, medium, and high hazard-identification skills) across various types of hazards. Then, multivariate ANOVA (MANOVA) was used to evaluate the impact of workers' hazard-identification skills on their visual attention. To further investigate the effect of hazard identification skills on the dependent variables (eye movement metrics), two distinct processes followed: separate ANOVAs on each of the dependent variables, and a discriminant function analysis. The analyses indicated that hazard identification skills significantly impact workers' visual search strategies: workers with higher hazard-identification skills had lower dwell-time percentages on ladder-related hazards; higher fixation counts on fall-to-lower-level hazards; and higher fixation counts and run counts on fall-protection systems, struck-by, housekeeping, and all hazardous areas combined. Among the eye-movement metrics studied, fixation count had the largest standardized coefficient in all canonical discriminant functions, which implies that this eye-movement metric uniquely discriminates workers with high hazard-identification skills and at-risk workers. Because discriminant function analysis is similar to regression, discriminant function (linear combinations of eye-movement metrics) can be used to predict workers' hazard-identification capabilities. In conclusion, this study provides a proof of concept that certain eyemovement metrics are predictive indicators of human error due to attentional failure. These outcomes stemmed from a laboratory setting, and, foreseeably, safety managers in the future will be able to use these findings to identify at-risk construction workers, pinpoint required safety training, measure training effectiveness, and eventually improve future personal protective equipment to measure construction workers' situation awareness in real time.

Examining the Relationship between Construction Workers’ Visual Attention and Situation Awareness under Fall and Tripping Hazard Conditions: Using Mobile Eye Tracking

“…Apart from a minor exception, these findings affirm many previous laboratory-based eye-tracking studies. However, some previous construction safety studies that used eye tracking in the laboratory found that workers with higher hazardidentification skills dwelt less on hazards (Hasanzadeh et al 2017a, b), a finding that diverges from the results obtained with the mobile eye tracker used in the current study. This discrepancy can be explained by comparing the experimental conditions in the laboratory and real world.…”

“…Attention is a selection process that determines which items are selected for subsequent processing (Wickens et al 2013). Balance between selective/focused attention (focus on only one stimulus) and divided/distributed attention (splitting attention between two or more tasks/objects) reflects both the amount and quality of information that an individual is able to perceive, process, and interpret from the environment (Hasanzadeh et al 2017a, b). In a dynamic environment, identifying relevant visual information and determining which information requires additional processing is important for individuals to maintain a safe level of performance (Kaber et al 2016).…”

“…The immense potential of using such eye tracking to improve construction safety has led to an increasing number of laboratorybased studies in recent years. These studies have measured the effect of safety training and knowledge, years of experience, personality, risk perception, and past injury exposure on workers' attentiveness and ability to identify hazards (Bhoir et al 2015;Hasanzadeh et al 2016Hasanzadeh et al , 2017a. Furthermore, previous studies have shown that monitoring the eye movements and attentional allocation of workers in real time may be beneficial in detecting at-risk workers who have lower situation awareness (Hasanzadeh et al 2017b) and identifying the hazards that they may fail to detect for the purpose of developing personalized safety training in the future (Hasanzadeh et al 2017d).…”

“…Interestingly, however, no study has empirically measured the influence of situation awareness on attentional allocation or how situation awareness affects tripping-hazard detection. Furthermore, although some studies have investigated the role of attention in accidents in construction safety (e.g., Hasanzadeh et al 2017a, b), most of these studies have been conducted in laboratory settings, which limits their extension to a real construction environment.…”

Role of Personality in Construction Safety: Investigating the Relationships between Personality, Attentional Failure, and Hazard Identification under Fall-Hazard Conditions

“…More recently, Hasanzadeh et al (2017c) expanded the application of eye-movement metrics to examine how working-memory load impacts a worker's attentional allocation and the detection of potential hazards in construction. Working memory (also known as short-term memory) refers to the mental workspace that offers limited capacity for maintaining information for short durations (Hitch and Baddeley 2017; Gevins et al 1998).…”