Measuring the emotional validity of driving simulators

Simulators offer an alternative medium to investigate issues with driving and to conduct vehicle control and situation awareness tests. To ensure transferability of research findings, drivers’ behaviour and reactions within vehicle simulators should be comparable to those observed on real roads. However, various questions relating to simulator validity have been raised, often focused on physical dimensions of fidelity (does the simulator look and feel like the real-world?), rather than psycho-physiological properties (does it replicate the relevant emotional and cognitive factors?). To address whether drivers in simulators behave and emotionally express themselves in response to perceived hazards as would be expected in the real-world, 24 drivers - 12 in a low fidelity and 12 in medium-fidelity simulator - drove on a rural road and encountered an emergency braking event (a vehicle pulling out from a parked position) towards the end of the drive. Drivers’ subjective responses were measured through an Emotion Questionnaire, nonverbal expressions (facial, vocal, gestures and postural movements) of emotion response and physiological measures of Heart-Rate (HR), Respiration-Rate (RR) and Breathing-Wave Amplitude (BWA). Drivers’ subjective responses to the emotion items showed higher ratings on the negative emotions of anger, fear, disgust, sadness and surprise during the emergency braking event (the hazard phase) compared to the non-hazard phase. Similar results were shown for drivers’ HR, RR and BWA measures. Furthermore, drivers exhibited realistic reactions and emotional gestures e.g. withdrawal of the head back towards the vehicle head restraint, and tensing of arms as if bracing for an impact. Facial expressions revealed a continuity of negative and adaptive emotional expressions. Results also showed comparability across measures taken from both simulators and the literature for equivalent on-road situations.