A Neuroergonomics Approach to Mental Workload, Engagement and Human Performance

Abstract

The assessment and prediction of cognitive performance is a key issue for any discipline concerned with human operators in the context of safety-critical behavior. Most of the research has focused on the measurement of mental workload but this construct remains difficult to operationalize despite decades of research on the topic. Recent advances in Neuroergonomics have expanded our understanding of neurocognitive processes across different operational domains. We provide a framework to disentangle those neural mechanisms that underpin the relationship between task demand, arousal, mental workload and human performance. This approach advocates targeting those specific mental states that precede a reduction of performance efficacy. A number of undesirable neurocognitive states (mind wandering, effort withdrawal, perseveration, inattentional phenomena) are identified and mapped within a two-dimensional conceptual space encompassing task engagement and arousal. We argue that monitoring the prefrontal cortex and its deactivation can index a generic shift from a nominal operational state to an impaired one where performance is likely to degrade. Neurophysiological, physiological and behavioral markers that specifically account for these states are identified. We then propose a typology of neuroadaptive countermeasures to mitigate these undesirable mental states.

Keywords: degraded attentional and executive mental states; mental workload; neuroergonomics; performance prediction; task engagement.

FIGURE 1

The dopamine pathway exerts a quadratic control over the PFC. A low or a high release of this neurochemical depresses PFC activation whereas an adequate concentration ensures optimal executive functioning (Vijayraghavan et al., 2007; Robbins and Arnsten, 2009). These neurobiological considerations bring interesting highlights to understand the mechanisms underlying the Yerkes and Dodson inverted-U law and the dynamic adaptability theory (Hancock and Warm, 1989). They also provide a relevant prospect to relate motivational aspects to behavioral responses. The noradrenaline pathway mediates the PFC activity and executive functioning in a similar fashion (see Aston-Jones and Cohen, 2005).

FIGURE 2

Performance, arousal and task engagement: the green zone conceptually describes the operator’s “comfort zone” where performance is optimal. The degraded mental states are mapped across a “task engagement” axis and an “arousal” axis. Interestingly, this point of view makes it possible to link the notion of engagement and degraded behavior in a simple way.

FIGURE 3

Left part: Several types of stressors can yield to the deactivation of the DLPFC and in return drastically induce collapse of performance. Right part: An illustration with the N-Back task: the right-DLPFC deactivates when the task demands exceed mental capacity (7-Back condition) and is associated with reduced performance efficacy and effort withdrawal (from Fairclough et al., 2019).

FIGURE 4

The three types of Neuroadaptive countermeasures dedicated to mitigate the undesirable mental states. Inattentional deafness and Inattentional blindness mental states were merged into “Inattentional phenomena” as no neuroadaptive countermeasure were implemented to explicitly address failure of auditory attention to the exception of multimodal alerts. Moreover, no adaptive automation-based solutions were designed to prevent from inattentional states. This demonstrates the need to conduct more research in this direction.