Paper of the week: Acute stress responses to simulated and real-world driving

Johnson, M. J., Chahal, T., Stinchcombe, A., Mullen, N., Weaver, B., & Bédard, M. (2011). Physiological responses to simulated and on-road driving. International Journal of Psychophysiology, 81(3), 203-8.

Driving is inherently stressful. Sudden events can occur at a moment’s notice forcing the driver to take sudden evasive measures. Therefore, perceived risk and anticipation are likely to elicit physiological changes as a result of increased sympathetic nervous system activity.

Two approaches were used in this study to investigate these effects. First, a driving simulator was used that included two sudden events: a car pulling out unexpectedly and traffic lights changing from green to amber. In a second experiment simulated driving was compared to real-world driving. Physiological parameters monitored included heart rate (HR) via ECG, oxygen consumption, and respiratory rate.

During real-world driving average heart rate increased by 6 bpm, respiratory rate increased by over 2 L/min, and oxygen consumption increased by 550 μl/kg/min. Similar increases in oxygen consumption and respiratory rate were found during simulated driving, indicating a comparable level of engagement. The only difference was that HR increases were greater during real-world as opposed to simulated driving, which is consistent with increased psychological stress in light of greater perceived consequences. During the simulated test, mean HR increased by 4 bpm in response to a car pulling out suddenly. A similar HR increase was seen when a green traffic light suddenly turned amber, prompting braking.

These results show that changes in perceived risk and decision making during driving – even when there are no real consequences – elicits rapid, acute stress responses. That simulated driving was also physiologically arousing may have implications for the use of simulators in early driver training.

16 December 2011