Effects on low doses of psychoactive substances are quite weak and difficult to measure. Furthermore, if sedative effects or vigilance reduction are to be investigated a methodological and practical issue is to induce the effect rather than wait for it. Therefore, a new rationale is introduced that adds high effort episodes into normal tasks. We term this approach "MaxMin" method. In this approach we give subjects the chance to remain vigilant by operating more actively. This self-activation is possible in early stages of fatigue only, whereas at the last stage subjects tend to reduce the stress. In our experimental design subjects had to drive a monotonous route in a simulator and were instructed to stress themselves at predefined episodes by driving as fast as possible. After each trip (about 25 min monotonous route and 5 min driving with high demands; 11 trips overall) subjective ratings and BAC were measured. Subjects of one group consumed alcohol aimed to reach a peak BAC of 0.5 ‰ and were compared to the non-alcohol group. The alcohol group drove faster within the periods of high demand. Their lane deviation was increased during the fast trips as well as during the normal epochs. Physiological data on EEG and eyelid closure will be presented to confirm the hypothesis of the self-activational process. (Abstract only) (Author/publisher) For the covering abstract of the conference see ITRD Abstract No. E201067.
Abstract