Situation Awareness (SA) comprises an individual’s perception, comprehension, and projection of the external environment within a defined temporal and spatial situation (Endsley, 1995). Prior research has found that approximately 85% of aviation safety incidents attributed to human error are linked to SA error or loss (Moon & Lee, 2020). According to the SA information processing model, Working Memory (WM) serves as the cornerstone of SA, particularly through the utilization of a mental model within WM to accurately project situational development, thus forming the basis for sound decision-making (Endsley, 1995). Furthermore, Wickens (2002a) categorized SA into spatial awareness, system awareness, and task awareness. Maintaining proficient spatial SA is imperative for ensuring the precise projection of spatial information changes during activities such as flight, tower monitoring, and driving, thereby serving as a prerequisite for operators and task performers, including pilots, air traffic controllers, and drivers. Consequently, exploring the mechanisms of WM involved in the maintenance and updating of spatial SA projection not only offers theoretical insights into human error but also provides practical guidance for the training of relevant professionals.
In comprehensive studies on SA, the aspect related to SA projection often concerns changes in spatial information, with particular attention to the impact of distraction on spatial SA projection. Survey studies on driving have found significant negative effects of distraction on driving behaviors related to spatial SA projection, such as safe overtaking and lane changing (Yang et al., 2020). Research on simulated driving tasks has shown that when distraction introduces a significant workload (such as when drivers answer phone calls), they tend to overlook or forget details of spatial information changes, thus impairing spatial SA projection and affecting the accuracy of predictions of future vehicle movements (such as drivers’ predictions of intersection safety) (Harbluk et al., 2007; Strayer et al., 2016; Frank et al., 2023). Studies on simulated flight monitoring or decision-making tasks have found that distraction can impair spatial SA projection, affecting performance on monitoring or decision-making tasks involving changes in spatial information (such as projecting the time required for an aircraft to reach a target altitude or location) (Fu et al., 2012; Liu, 2015; Xie et al., 2023).
The negative impact of distraction on spatial SA projection may be related to WM. Prior studies have found that the limitations of WM storage time and capacity determine the upper limit of SA (Gutzwiller & Clegg, 2013; Nilsson et al., 2021). According to the theory of limited cognitive resources, the processing of distraction information competes with main task for limited cognitive resources, leading to attentional diversion (Wickens, 2002b). This not only reduces the effective information input into WM but also alters the allocation of cognitive resources, thereby affecting WM processes (Fu et al., 2012; Xie et al., 2023). Hence, one can speculate that distraction’s negative impact on spatial SA projection may be associated with impaired WM functionality. Prior studies have used different types of distraction to induce different modalities of WM load, focusing on the relationships among the visuospatial sketchpad, phonological loop, and SA. Some studies involving spatial SA projection have found that auditory distraction during the presentation of situations impairs spatial SA projection, implying a connection between the phonological loop and spatial SA projection (Muhrer & Vollrath, 2011; Xie et al., 2023). By contrast, other studies have shown that visual distraction or visual-spatial distraction is more detrimental to spatial SA projection than auditory distraction, thus implying that the visuospatial sketchpad is crucial in forming spatial SA projection (Liu, 2015; Karthau et al., 2020). Meanwhile, some studies on the relationship between WM capacity and SA have found no association between WM capacity and spatial SA projection (Gonzalez & Wimisberg, 2007; Kaber et al., 2016).
It is clear, then, that the current conclusions regarding whether distraction can directly impact spatial SA projection and how different types of distraction affect it remain inconsistent, and the WM mechanisms underlying the maintenance and updating of spatial SA projection remain unclear. There are two main reasons for this:
Measurement error
The Situation Awareness Global Assessment Technique (SAGAT) is the most commonly used method for measuring SA (Endsley, 2021); it involves freezing a situation during tasks and presenting situation-related questions. However, during the situation freeze period, participants may experience memory decay, leading to recovery biases in situation tasks and affecting their response accuracy (de Winter et al., 2019). In addition, when multiple questions are presented in a list format, the random content or order of the questions may lead participants to answer other, unrelated questions before answering the spatial SA projection questions, potentially impacting measurement both in terms of content and time, and thereby creating an illusion that different modalities of distraction conditions can affect spatial SA projection, obscuring the real WM mechanisms involved. Furthermore, the SAGAT is text-based, with questions regarding spatial SA projection that mainly test the participant’s memory of situation information and event reasoning abilities, such as “Based on the altitude and rate of climb displayed on the instrument at the pause point, how long will it take for the aircraft to climb to 4000 feet”. Such an approach merely assesses the participant’s WM and reasoning abilities regarding the pause point instrument information, failing to represent their true spatial SA projection.
Timing of distraction application
SA is a cognitive, cyclical process of continuous deepening and updating of perception, comprehension, and projection. However, in studies to date, distraction has often persisted during the situation presentation stage (Karthau et al., 2020), with the implication that distraction acts on spatial SA projection through two pathways. First, distraction can influence perception, altering the content input into WM, and thus affecting spatial SA projection generation, ultimately leading to inaccurate projection. For example, auditory distraction can reduce individuals’ total gaze time and average gaze rate on the monitoring task interface, thereby affecting projection (Xie et al., 2023). Second, distraction can directly affect the information processing process related to the maintenance and updating of spatial SA projection, impairing projection by competing with the corresponding WM subsystems for cognitive resources. Therefore, applying distraction during the situation presentation stage fails to separate the two pathways of action, making it difficult to accurately determine how distraction affects the maintenance and updating of spatial SA projection and its WM mechanisms.
For these reasons, the current study did not use SAGAT. Instead, it employed a concretized approach, namely positional judgment, to measure spatial SA projection by creating a task situation of flight monitoring. Furthermore, to distinguish the two pathways through which distraction affects spatial SA projection, a masking paradigm was used to simulate situation absence and disrupt the complete cognitive cycle of SA, while simultaneously applying distraction that directly affects the cognitive processing involved in the maintenance and updating of spatial SA projection. Specifically, to systematically investigate the WM mechanism underlying the maintenance and updating of spatial SA projection, the current study conducts three experiments.
First, in regard to the limited storage time of WM, Experiment 1 investigates the influence of distraction on spatial SA projection under different durations of situation absence. The following hypothesis is proposed:
H1
As the duration of situation absence increases, spatial SA projection deteriorates, and is worse under conditions of distraction than those of no distraction. This suggests a direct connection between WM and the maintenance and updating of spatial SA projection, and distraction can impair the maintenance and updating of spatial SA by affecting this connection.
Second, if H1 holds true, then the question arises of how the central executive system of WM functions, and in particular the question of whether its refreshing function is closely related to the maintenance and updating of spatial SA projection. To address this, Experiment 2 compares the effects of different durations of distraction under fixed conditions of situation absence duration on spatial SA projection. The following hypothesis is thus proposed:
H2
Continuous distraction during situation absence can impair spatial SA projection, and if the distraction is interrupted, the projection will recover. This suggests that the effect of distraction on the maintenance and updating of spatial SA projection is achieved through continuous inhibition of the refreshing function of the central executive system.
Finally, if both H1 and H2 hold true, then the question arises of how the central executive system allocates cognitive resources, and whether both the visuospatial sketchpad and the phonological loop play important roles in the maintenance and updating process of spatial SA projection. Experiment 3 explores differences in the effects of visual-spatial distraction and auditory distraction on spatial SA projection. Considering that the limited storage capacity of WM can affect the extent to which distraction affects spatial SA projection, this experiment also compares the differences in the effects of two types of distraction (i.e., visual-spatial and auditory) on spatial SA projection in single-object motion and multiple-object motion situations. The following hypothesis is thus proposed:
H3
Visual-spatial distraction is more detrimental to spatial SA projection than auditory distraction, and the complexification of object relations only amplifies the impact of visual-spatial distraction on spatial SA projection. This suggests that spatial SA projection has a capacity-limited maintenance and updating mechanism, which is associated with the visuospatial sketchpad and has a smaller association with the phonological loop.