THE JOINT EFFECT OF TASK CHARACTERISTICS AND EXTRAVERSION ON THE PERFORMANCE, WORKLOAD, AND STRESS OF SIGNAL DETECTION

incorporated individual differences into the model (Szalma, 2008). The purpose was to investigate how the task characteristics of information rate (event rate) and information structure (number of displays to be monitored) interact with participant personality (extraversion) to affect the performance, workload, and stress associated with a cognitive vigilance task. As expected, extraversion moderated the relationship of task characteristics to performance, global workload, distress, and task engagement, although the relationship of extraversion to the worry dimensions of stress was not significant. The dynamic adaptability theory of performance under stress (Hancock & Warm, 1989) explicitly identifies the task a person performs as the most proximal source of stress input. The model defines two task dimensions, information structure (the spatial organization of a task) and information rate (the temporal properties of a task). The model predicts that across a wide range of task demands individuals can maintain a stable adaptive state. However, as demands are increased or decreased to extremes, adaptation failures occur (e.g., increased workload and stress; performance decrements). Szalma (2008) incorporated individual differences into the model, asserting that because stress results from a transaction between the person and the task (Matthews, 2001) models of stress and performance should incorporate both person and task characteristics to fully account for stress effects. In particular, Szalma (2008) proposed that the level of task demand at which the threshold of adaptation is reached may vary as a function of affective traits. In addition, the slope of the decline in adaptation may also vary as a function of observer traits. The current study was designed to test these predictions by manipulating the task characteristics of information rate and structure and evaluating whether the effect of task properties on performance, workload, and stress varies as a function of extraversion, a trait that has been associated with performance and stress of cognitive tasks (Matthews et al., 2009)