It has been reported that a group of accident-prone drivers showed a greater variation (standard deviation) in choice reaction times (RTs) than did non-accident-prone drivers. However, it is not clear which is the cause of the driver's sudden delay, a cognitive process or a reaction process. To investigate this problem, the event-related potential (P300) and RT of youths and the elderly were recorded using a driving simulator. It was supposed that the P300 latency reflected the termination of the cognitive process and the subtract value, RT-P300, reflected the reaction process. The number of subjects who had a significant correlation between RT and RT-P300 was more than that between RT and the P300 latency. These results indicate the variance of RT was caused by the variance of the reaction process. Moreover, the brain resource capacity in youths seemed to fluctuate according to tasks. For the covering abstract see ITRD E113725 (C 22328 CD-ROM).
Abstract