Main sequence: an index for detecting mental workload variation in complex tasks.

The primary aim of this study was to validate the saccadic main sequence, in particular the peak velocity [PV], as an alternative psychophysiological measure of Mental Workload [MW]. Taking the Wickens' multiple resource model as the theoretical framework of reference, an experiment was conducted using the Firechief® microworld. MW was manipulated by changing the task complexity (between groups) and the amount of training (within groups). There were significant effects on PV from both factors. These results provide additional empirical support for the sensitivity of PV to discriminate MW variation on visual-dynamic complex tasks. These findings and other recent results on PV could provide important information for the development of a new vigilance screening tool for the prevention of accidents in several fields of applied ergonomics.