Neil R. de Joux

A functional near-infrared spectroscopy study of sustained attention to local and global target features

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.

Friendly Fire and the Sustained Attention to Response Task

Objective: We investigated whether losses of inhibitory control could be responsible for some friendly-fire incidents. Background: Several factors are commonly cited to explain friendly-fire incidents, but failure of inhibitory control has not yet been explored. The Sustained Attention to Response Task (SART) could be a valid model for inhibition failures in some combat scenarios. Method: Participants completed small-arms simulations using near infrared emitter guns, confronting research assistants acting as friends or foes. In Experiment 1, seven participants completed three conditions with three different proportions of foes (high, medium, low). In Experiment 2, 13 participants completed high-foe (high-go) and low-foe (low-go) versions of a small-arms simulation as well as comparative computer tasks. Results: Participants made more friendly-fire errors (errors of commission) when foe proportion was high. A speed–accuracy trade-off was apparent, with participants who were faster to fire on foes also more likely to accidentally shoot friends. When foe proportion was higher, response times to foe stimuli were faster, and subjective workload ratings were higher. Conclusion: Failures of inhibitory control may be responsible for some friendly-fire incidents and the SART could be a suitable empirical model for some battlefield environments. The effect appears to be disproportionately greater at higher foe proportions. The exact nature of performance reductions associated with high-foe proportions requires further investigation. Application: The SART may be a useful model of friendly-fire scenarios. It could be used to indicate a soldier’s likelihood to commit a friendly-fire mistake and to identify high-risk environments.

Cognitive Resource Demands During Climbing Considerations for Communication Technologies

Climbing is a demanding physical activity often requiring communication with others. In sport and recreational climbing communication may be with belayers and team members. In occupations requiring climbing, like firefighting and search and rescue, this communication demand is even more pressing. Theories in human factors, such as Multiple Resource Theory (MRT), may be useful in designing and selecting communication technology appropriate for climbers. We present the results of a series of dual-task studies in which climbing is combined with a communication task. These results indicate climbing is highly cognitively demanding. Based on these results and MRT, we suggest the need for communication equipment that augments the climber’s memory and caution regarding the use of communication equipment using visual or tactile modalities.

Go-stimuli proportion influences response strategy in a sustained attention to response task

The sustained attention to response task (SART) usefulness as a measure of sustained attention has been questioned. The SART may instead be a better measure of other psychological processes and could prove useful in understanding some real-world behaviours. Thirty participants completed four Go/No-Go response tasks much like the SART, with Go-stimuli proportions of .50, .65, .80 and .95. As Go-stimuli proportion increased, reaction times decreased while both commission errors and self-reported task-related thoughts increased. Performance measures were associated with task-related thoughts but not task-unrelated thoughts. Instead of faster reaction times and increased commission errors being due to absentmindedness or perceptual decoupling from the task, the results suggested participants made use of two competing response strategies, in line with a response strategy or response inhibition perspective of SART performance. Interestingly, performance measures changed in a nonlinear manner, despite the linear Go proportion increase. A threshold may exist where the prepotent motor response becomes more pronounced, leading to the disproportionate increase in response speed and commission errors. This research has implications for researchers looking to employ the SART and for more applied contexts where the consequences of response inhibition failures can be serious.

The effect of task-relevant and irrelevant anxiety-provoking stimuli on response inhibition

The impact of anxiety-provoking stimuli on the Sustained Attention to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997), and response inhibition more generally, is currently unclear. Participants completed four SARTs embedded with picture stimuli of two levels of emotion (negative or neutral) and two levels of task-relevance (predictive or non-predictive of imminent No-Go stimuli). Negative pictures had a small but detectable adverse effect on performance regardless of their task-relevance. Overall, response times and rates of commission errors were more dependent upon the predictive value (relevance) of the pictures than their attention-capturing nature (i.e., negative valence). The findings raise doubt over whether anxiety improves response inhibition, and also lend support to a response strategy perspective of SART performance, as opposed to a mindlessness or mind-wandering explanation.

The Configural Properties of Task Stimuli do Influence Vigilance Performance

Abstract Sixty-one participants performed a sustained attention task in which they were required to respond to a critical signal requiring feature discrimination. Three separate groups performed the task with different global display configurations. The local feature elements (directional arrow shapes) were displayed on either a circle, a circle broken apart or a reconnected figure. For two of the groups, the entire display consisted of a clear global shape (circle and reconnected), and for one of the groups, the display had no discernible global element (broken circle) despite the critical signal being the same for all the groups. Analyses of hit rate and A′ scores indicated that the broken circle group had impaired performance compared to the global figure groups. A configural superiority effect was found in which performance was improved by having a global shape property to the entire display. These results provide a behavioural base for further research utilizing measures of cerebral activation, as cerebral activity during vigilance tasks may be dependent on both task difficulty and hierarchical aspects of the display. The configurable or hierarchical aspects of vigilance displays may be critical in understanding sustained attention performance and its hemispheric lateralization.

Friendly Fire and the Proportion of Friends to Foes

Losses of inhibitory control may be partly responsible for some friendly fire incidents. The Sustained Attention to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) may provide an appropriate empirical model for this. The current investigation aimed to provide an ecologically valid application of the SART to a small arms simulation and examine the effect of different proportions of enemy to friendly confederates. Seven university students engaged in a small arms simulation where they cleared a building floor using a near-infrared emitter gun, tasked with firing at confederates representing enemies and withholding fire to confederates representing friends. All participants completed three conditions which were differentiated by the proportion of enemies to friends present. As hypothesized, participants failed to withhold responses more often when the proportion of foes was higher, suggesting that a prepotent motor response routine had developed. This effect appeared to be disproportionately more substantial in the high foe condition relative to the others. Participants also subjectively reported higher levels of on-task focus as foe proportions increased, suggesting that they found this more mentally demanding. Future research could examine closer the nature of the performance reductions associated with high proportions of foes, as it appears that this is more complex than a simple linear relationship.

Judgments of Team Workload and Stress: A Simulated Unmanned Aerial Vehicle Case

How do people perceive team workload and stress? Is team workload and stress simply judged to be the sum of the constituent parts, or do people perceive interactive effects between task demands and the team member’s respective skill levels? The present study explored whether people have an intuitive theory of team stress and workload that they use to predict team’s stress and workload in performance contexts. Participants were trained for five weeks on a UAV team task, and then were asked to rate eight hypothetical scenarios for team stress and workload. The present results indicate the participants basically perceived team workload and stress as the sum of the constituent parts in regards to team members.

The effects of a transition between local and global processing on vigilance performance

Sixty participants performed a sustained attention task in which they were required to perform either global or local feature discrimination. Two groups required just one type of discrimination, while the remaining two groups started on one type of discrimination before transitioning to the other type halfway through. A transition resulted in worse performance when compared to no transition. It was also found that the local discrimination group showed improved performance over time compared to the global discrimination group. Functional near-infrared spectroscopy (fNIRS) was used to measure blood oxygenation during the task and was used as an index of cerebral hemodynamic activity. Total oxygenation was found to increase more in global discrimination tasks. It was also found that the left prefrontal cortex showed little change in nontransition tasks while in transition tasks it followed the same trend as the right prefrontal cortex. Combined with performance data, it suggests that an increased utilization of bilateral resources may in some cases improve performance over time.

Real-time quantitative performance feedback during strength exercise improves motivation, competitiveness, mood, and performance

Providing quantitative feedback on performance in real-time appears to improve performance in a strength training context. Less is known about the associated effects on psychological variables. Fifteen rugby athletes performed a strength training exercise both with and without objective performance feedback provided in real-time. Feedback increased performance, consistent with previous research. Feedback also led to higher ratings of task competitiveness, state motivation, mood, and workload. These findings provide insight into possible underlying mechanisms responsible for the feedback’s facilitative effects on performance. The findings also suggests that providing this type of feedback may have benefits within other industries, where attempts are frequently made to increase adherence to exercise and rehabilitation programs. This research carries important implications for the design and use of technology within both the sports science and healthcare industry.