Building “Situation Awareness” construct from the geometric-functional features of a work environment

In the last decades, the improvement of technology provided sophisticated systems necessary in “operational environments” where individual and environmental safety is at risk. Most systems acquire information from the environment, detect hazards and spread communications for “operator” support. In the operational environments involving human-systems interaction the operator is usually required to allocate his/her attention for monitoring the systems for long periods. Different sources of information (e.g., external environments or other operators) and its typology (e.g., visual or auditory) are designed in developing “complex systems” in order to solve the work overload problem. In Human Factors / Ergonomics (HF/E) domain the mental workload measure is widely accepted to be the most reliable approach to access both operator functional state (OFS) and human performance factors. However, a further construct named as “Situation Awareness” (SA) has been introduced in order to better understand the OFS in complex environments. Endsley (1995) provided a formal definition of SA as the individuals’ ability to (a) perceive elements in the environment within a volume of time and space, (b) comprehend their meaning, and (c) predict their status in the near future. Although, this construct has immediately captured the interest of many HF researchers both an unique definition of SA and an highly validated measure are not available yet. Also, SA theory development appears to follow many applicative requirements neglecting several basic aspects such as a clear definition of the cognitive processes engaged, and the standardization (or formalization) of elements, events, interactions, goals and behaviors leading to different degrees of SA (see Flach, 1995 for a critical review). Furthermore, the increased use of teams in complex environments has shifted the focus from individual operator SA onto the “team SA” (TSA). Indeed, increases in bandwidth and technological tools may enable operators the means to work as networked teams and it is uncertain the TSA and human performance effects that may result. Different modes of communication (e.g. messaging vs. voice) may generate changes in SA and mental workload and affect operators’ performances differently. Operator readiness and performance need to be evaluated and supported in such a critical and dynamic environment. In the first study of this dissertation, it was developed a SA measure with the aim of separately assessing the three main cognitive abilities that defined the construct. A computer game of strategy inspired by the board game Risk! was used in the experimentation. Participants were assigned to teams and they communicated from separated locations via “instant messaging”. Results showed that team SA was mainly characterized by different styles of communication within the team. A strong relationship between TSA and information sharing was evident. Moreover, team members SA was also affected by the distance between the iconic representation of the agents involved in the task. In the third study of this dissertation a simulation of the ambulance dispatchers work was used as experimental task. Participants were required to pick the incoming calls (communications were PC simulated in this case) and to activate emergency rides as well as non-urgent transports. Heart rate variability and ocular scanning behavior were used as indicators of individual mental workload while the previously developed SA measure was adapted to a quite ecological operational environment. Results showed that SA variations were mostly affected by changes in physical features of the working situations. In particular, a higher spatial concentration of displayed information constrained the individual SA achievement that, conversely, benefited from a more spread distribution of information. Also, individual achieved a more accurate SA of the task events that were more salient than others. In other words, the physical features of the working environment showed to play a key role in the SA construct. This dissertation was firstly aimed at filling a gap in the literature for successfully understanding the relationship between situational physical features, functionality (or salience) of the task events, agents’ interaction (i.e. communications) and SA. The insights gained from this investigation may be used for updating the guidelines that designers use for developing technologies to support operators in individual and collaborative task.