An investigation into physiological responses in driving simulators: An objective measurement of presence

The main contribution of this paper to the Cognitive Ergonomics field is to propose a new approach of the behavioral validity´s assessment of driving simulators. In this paper, our ambition is to find a way of measuring “presence” to use it as a measure for ecological validity in driving simulators. In this way, the purpose of this study is especially to investigate the relationship between subjective ratings of presence and physiological responses in virtual driving environments. Six driving scenarios were, thus, created, resulting from crossing two independent variables, i.e., the visual realism of the virtual environment (three virtual environments were created ranging from very realistic to not realistic) and the degree of visibility on the road for each virtual environment (two conditions were proposed : very good visibility and very bad visibility). Whatever the scenario, the driving task was always to follow a red car without losing sight of its location. To measure subjective presence, attention and emotional involvement, Presence, and Mood questionnaires were used. As measures of physiological response, heart rate and skin conductance level were acquired and more specifically the heart rate variability (HRV) was calculated from the acquired ECG data. Driving performance (standard deviations of speed and lateral position) was also analyzed. Fourteen participants (25.4±4.5 years of age) were placed in a fixed base driving simulator and performed consecutively the six driving scenarios in a different order. The results show correlations between Presence Questionnaire scores and both HRV parameters (time and frequency domains) and skin conductance level. In the study, HRV parameters and skin conductance level appeared to indicate the participant´s degree of presence.