Effect of driving environment complexity and dual task on eye blink rate
Résumé
Eye measures have been shown to be relevant indicators of mental workload. Empirical results revealed a relationship between mental workload and eye blinks, depending on the task constraints. In a single-task, the blink rate seems to drop as a function of greater task complexity, while the opposite result has been found in a dual-task. The goal of this study was to examine the effect of driving-task complexity on blink rate, using a single versus a dual task. For the experiment, 20 participants drove in 3 driving environment complexities: low (dual-carriageway), medium (rural-road) and high (urban-road). Each condition was presented alone, or associated with a vocal reaction-time-task to an auditory stimulus. Results showed a strong effect of driving-task complexity, as blink rate decreased from low to high environment complexity. By contrast and differing from previous research, the dual-task condition didn’t affect blink rate. This suggests that the reaction time and the driving task were performed simultaneously, and that the reaction -time -task didn’t affect the driving -task. The effects of a dual task on blink rate might probably occur in case of attentional switching. It could be valuable to examine in a future experiment the effect of environment complexities on blink rate in a new dual-task paradigm: driving and mental-arithmetic.