Mental workload at roundabouts and its relationship to mindfulness -A driving simulator study using pupillometry and a spatial-auditory secondary task.

Abstract

An unfavorable amount of mental workload while driving has a negative impact on the driving performance and can therefore lead to accidents. Assistance systems that are capable of measuring the drivers’ mental state based on psychophysiological data and intervene accordingly are a promising possibility in particular for supporting a driver in phases of high mental workload. The current study aimed at contributing to the development of an according assistance system. Thus, the mental workload was measured in this study via a spatial auditory secondary task and the pupil variance while the participants drove through a roundabout. A second aim of the study was to exploratively examine the impact of Mindfulness on mental workload, therefore, the German adaption of the MAAS short was used to measure Trait Mindfulness. 23 participants completed a simulated driving scenario which consisted of multiple roundabouts. A task analysis revealed seven roundabout phases in which different levels of mental workload can be expected. In each of these seven roundabout phases, a secondary task stimuli was presented and the reaction time to this stimuli was recorded. In addition, the pupil variance was assessed as an indicator for mental workload. The results showed an increasing pupil variance and reaction time in roundabout phases in which many contact points with other road users were given and in which much steering and slow driving was required. After the cognitive demanding task was fulfilled the reaction time remained impaired while the pupil variance already decreased to normal levels. Regarding the Mindfulness, the results showed an increased reaction time but decreased pupil variance for participants with a higher Trait Mindfulness when high levels of mental workload were induced. When moderate levels of mental workload had been induced, the correlation between Mindfulness and the reaction time remained, although slightly mitigated, while the correlation between Mindfulness and pupil variance disappears.