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Objective: To investigate whether depleting self-control prior to vigilance results in a steeper vigilance decrement. Background: The resource-control theory of vigilance asserts that an inherent bias toward self-generated mind-wandering draws attentional resources away from the primary task. This study seeks to test whether depleting self-control, the potential mechanism of self-generated mind-wandering, results in poorer vigilance performance. Method: This study featured a between-subjects design where participants either completed a typing task that depleted self-control resources or a standard typing task that did not require self-control before performing a vigilance task. In the self-control depletion condition, participants typed a passage while omitting any “e” and “space” keys. In the standard typing task, participants typed the same passage without skipping any keys. Following both typing tasks, participants in both conditions completed an identical 12-min vigilance task. Results: Results demonstrated decreased accuracy and increased reaction times over time for both groups. Depleting self-control did not result in significant differences in accuracy, reaction time, nor a steeper vigilance decrement. Conclusion: These results provide evidence against resource-control theory and self-control as an explanation for vigilance, and provide further support for cognitive resource theory as the predominant explanation for vigilance impairments. Application: It is still unclear exactly what constitutes a “resource.” A better understanding of the nature of these resources can help researchers and practitioners identify how they can be replenished, which could enhance human performance in situations requiring vigilance such as baggage screening.

Measuring workload accurately is critical for human factors research and applications. However, if the instruments we use to measure workload are burdensome for participants to complete, we may find ourselves in the ironic position of increasing workload simply by measuring it. We present a pair of studies that suggest the NASA-TLX, a widely-used workload metric, increases workload for participants who complete it, and consequently may hurt performance and upwardly bias the estimates it produces. We found that repeated administration of the NASA-TLX increased workload by 18%, and more than doubled the performance decrement on a simple vigilance task. Single-item measures may be a simple way to avoid burdening participants unnecessarily while still obtaining valuable insight into participant cognitive state. In line with the attentional resource theory, we validate a measure that asks participants to ‘think about [their] brain as an engine,’ and to indicate inside a rectangle ‘how much gas [they] h...

Given that older adults are remaining longer in the workforce, their ability to perform demanding cognitive tasks such as vigilance assignments needs to be thoroughly examined, especially since many vigilance assignments affect public safety (e.g., aviation, medicine, and long distance driving). Previous research exploring the relation between aging and vigilance is conflicted, with some studies finding decreased vigilance performance in older adults but others finding no effect of age. We sought a better understanding of effects of age on vigilance by assessing neurophysiological change over the course of a vigil in young (aged 18-24) and healthy older (aged 66-77) adults. To measure temporal changes in cerebral blood flow, participants underwent functional transcranial doppler (fTCD) recording during a one-hour vigilance task. Based on research showing a compensatory effect of increased left hemisphere activation during vigilance in young adults and the ‘hemispheric asymmetry reduction in older adults’ (HAROLD) model, we predicted that during vigilance our older adults would show greater left hemisphere activation but perform at a similar level compared to young adults. While cerebral blood flow velocity (CBFV) declined over time in both groups, only young adults showed the typical right-lateralized CBFV pattern. Older adults showed greater left hemisphere activation consistent with the HAROLD model. However, the increased left hemisphere activation did not appear to be compensatory as the older adults performed at a significantly lower level compared to young adults over the vigil. Findings are discussed in terms of the HAROLD model of healthy aging and the resource theory of vigilance.