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Abstract: We examined whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed a number detection task for 37.3min using either a Sustained Attention to Response Task (SART; high Go low No-Go) or a more traditionally formatted vigilance task (TFT; high No-Go low Go) response format. Participants performed these tasks using either a regular fixed ordered stimuli set (1–9, sequentially repeated), in which the target number appeared predictably, or a random order (1–9, random presentation), in which the target number appeared at random. We utilized functional near infrared spectroscopy (fNIRS) to measure cerebral oxygenation levels in the right and left frontal areas. We also used post-task participant reports of arousal, and conscious thoughts occurring during the tasks. Performance differed for the both response format and target predictability. Greater right than left frontal hemisphere activation occurred in the TFT than the SART with time-on-task. In addition, the SART response format resulted in elevated self-reports of task-related thoughts than the TFT response format. The results suggest the SART, random or fixed ordered, places high response inhibition, not necessarily sustained attention, demands on participants. Elevated levels of task-related thoughts during the SART format condition in comparison to the TFT condition does not appear to be in accord with the claim that the SART induces mindlessness. [Copyright &y& Elsevier]

Abstract: Despite a long history of vigilance research, the role of global and local feature discrimination in vigilance tasks has been relatively neglected. In this experiment participants performed a sustained attention task requiring either global or local shape stimuli discrimination. Reaction time to local feature discriminations was characterized by a quadratic trend over time-on-task with performance levels returning to initial levels late in the task. This trend did not occur in the global shape discrimination task. Functional near-infrared spectroscopy (fNIRS) was utilized in this study as an index of cerebral activation. In both tasks there was increased right hemisphere relative to left hemisphere oxygenation and right hemisphere oxygenation increased with time-on-task. Left hemisphere oxygenation, however, decreased slightly in the global task, but increased significantly in the local task as task duration increased. Indeed, total oxygenation, averaging both right and left, increased more with time-on-task in the local discrimination task. Both the performance and physiological results of this study indicate increased utilization of bilateral cerebral resources with time-on-task in the local, but not the global discrimination vigil. [Copyright &y& Elsevier]

Abstract: In the present experiment, we used search asymmetry to test whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed feature present and feature absent target detection tasks using either a sustained attention to response task (SART; high Go low No-Go) or a traditionally formatted task (TFT; high No-Go low Go) response format. In addition to performance, we employed functional near infrared spectroscopy (fNIRS) to measure lateral cerebral oxygenation levels and self-reports of Tense Arousal, Energetic Arousal, task related and unrelated thoughts occurring during the tasks. Detections were lower and reaction times longer in the feature absent search than the feature present search regardless of response format. Detections were lower, but reaction times shorter in the SART than the TFT regardless of feature search. Greater right than left frontal hemisphere activation occurred in the SART than the TFT. In addition, the SART was more fatiguing based on self-reports than the TFT, but there were no differences in Task-Unrelated Thoughts across task conditions. Overall, the results suggest the SART places high response inhibition, not necessarily sustained attention, demands on participants. [Copyright &y& Elsevier]