Improving Vigilance Analysis Methodology: Questioning the Successive Versus Simultaneous Distinction

We describe a vigilance experiment of a successive task and a simultaneous task. Successive tasks require comparing the current stimulus on the screen to a representation in memory (i.e. making a declarative memory retrieval), whereas simultaneous tasks require making a comparative judgment based on information that is available on the screen. When analyzing the data from this experiment using conventional methods, there was an effect of time-on-task (i.e. block), an effect of task type, and an interaction between block and task type. These findings were consistent with previously reported studies regarding the successive and simultaneous vigilance task distinction, which interpret such findings as evidence that the decrement is more severe for successive tasks. But different results and conclusions are made when more appropriate analyses of the data are used, such as: including block as an interval variable instead of a categorical variable and making the dependent variable detection of critical signals ...