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INTRODUCTION The ability to notice behaviorally meaningful objects and events in the visual surroundings is fundamental to an operator's capacity to maintain performance in a complex environment. Indeed, Endsley's (1995) […], A set of studies examined the effects of cognitive distraction on visual scanning and change detection in natural traffic scenes. Experiment 1 found that a naturalistic hands-free phone conversation could disrupt change detection, thereby degrading the encoding of visual information and increasing the frequency of undetected changes. Data also revealed a tendency for conversation to impair knowledge-driven orienting of attention in older adults. Experiment 2 found that an attentive listening task produced no such effects. Actual or potential applications of this research include the design of displays and interventions to minimize the effects of cognitive distraction on human performance.

INTRODUCTION Bimodal Speech Perception Some research examining the perception of speech has been unimodal; the visual and auditory aspects of speech comprehension are investigated separately. For example, researchers examining the […], Attending to a single voice when multiple voices are present is a challenging but common occurrence. An experiment was conducted to determine (a) whether presenting a video display of the target speaker aided speech comprehension in an environment with competing voices, and (b) whether the "ventriloquism effect" could be used to enhance comprehension, as found by Driver (1996), using ecologically valid stimuli. Participants listened for target words from videos of an actress reading while simultaneously ignoring the voices of 2 to 4 different actresses. Target-word detection declined as participants had to ignore more distracting voices; however, this decline was reduced when a video display of the target speaker was provided. Neither a signal-detection analysis of performance data nor a gaze-contingent analysis revealed a ventriloquism effect. Providing a video display of a speaker when competing voices are present improves comprehension, but obtaining the ventriloquism effect appears elusive in naturalistic circumstances. Actual or potential applications of this research include those circumstances in which a listener must filter a relevant stream of speech from among multiple, competing voices, such as air traffic control and military environments.

INTRODUCTION In many complex systems, such as aircraft, nuclear power plants, and automobiles, little space is available in which to present information to the operator. As systems are engineered with […], A sequential or RAP COM (rapid communication) display was compared with a more conventional spatial display as participants monitored dynamically changing sets of three-digit numbers and responded to occasional target stimuli. In an effort to equate the stimulus-response compatibility of the two displays, we had participants respond to the targets with a chord keyboard in Experiment 1 and vocally in Experiment 2. We examined the influence of display duration on performance with the RAP COM and spatial formats by presenting stimuli at three different durations (400, 800, and 1200 ms). The influence of practice on performance with the RAP COM and spatial displays was also investigated. Participants responded to targets more quickly in the RAP COM than in the spatial displays at each of the three presentation durations and across more than 2000 trials of practice. Accuracy was influenced by the display presentation duration. Accuracy was higher for the RAP COM than for the spatial display at the 800-ms stimulus presentation duration in Experiment 1 and at the 800- and 1200-ms presentation durations in Experiment 2. The results are discussed in terms of the potential utility of RAP COM displays for complex, real-world systems.

We investigated the influence of extended wakefulness on automatic and nonautomatic processes in memory and visual search tasks. Subjects were trained in consistently mapped and variably mapped versions of each task, attaining automatic performance in the consistently mapped versions. We then recorded performance measures and event-related brain potentials for a 14-h period that began during the evening of the last day of training. Overall performance declined with extended wakefulness, but the benefits of consistently mapped training were retained throughout the night. Performance decrements consisted of an increase in nonresponses, increased response latencies, and decreased accuracies. P300 latencies increased, and P300 amplitudes decreased with extended wakefulness. When viewed together, reaction time and event-related brain potentials measures suggest that the locus of extended wakefulness effects was during early perceptual processes.

The main goal of the present study was to examine the feasibility of employing event-related brain potentials to measure dynamic changes in mental workload. Subjects performed two tasks, monitoring and mental arithmetic, both separately and together. Following an analysis of the performance, subjective workload ratings, and average ERP data in the single- and dual-task conditions, two different conditions from each of the tasks were selected for further analysis. A bootstrapping approach was employed to determine the amount of ERP data required to discriminate between these conditions. The results of these analyses indicated that (a) 90% correct discrimination could be achieved with from 1 to 11 s of ERP data, (b) the best ERP measures varied across tasks and subjects, and (c) the inclusion of temporal and spatial aspects of the ERP data improved the ability to discriminate among workload levels. The data is discussed with respect to real-time assessment of mental workload.

The effects of altitude on human performance and cognition were evaluated in a field study performed on Mount Denali in Alaska during the summer of 1990. Climbers performed a series of perceptual, cognitive, and sensory-motor tasks before, during, and after climbing the West Buttress route on Denali. Relative to a matched control group that performed the tasks at sea level, the climbers showed deficits of learning and retention in perceptual and memory tasks. Furthermore, climbers performed more slowly on most tasks than did the control group, suggesting long-term deficits that may be attributed to repeated forays to high altitudes.

Objective We implemented a gaze-contingent useful field of view paradigm to examine older adult multitasking performance in a simulated driving environment. Background Multitasking refers to the ability to manage multiple simultaneous streams of information. Recent work suggests that multitasking declines with age, yet the mechanisms supporting these declines are still debated. One possible framework to better understand this phenomenon is the useful field of view, or the area in the visual field where information can be attended and processed. In particular, the useful field of view allows for the discrimination of two competing theories of real-time multitasking, a general interference account and a tunneling account. Methods Twenty-five older adult subjects completed a useful field of view task that involved discriminating the orientation of lines in gaze-contingent Gabor patches appearing at varying eccentricities (based on distance from the fovea) as they operated a vehicle in a driving simulator. In half of the driving scenarios, subjects also completed an auditory two-back task to manipulate cognitive workload, and during some trials, wind was introduced as a means to alter general driving difficulty. Results Consistent with prior work, indices of driving performance were sensitive to both wind and workload. Interestingly, we also observed a decline in Gabor patch discrimination accuracy under high cognitive workload regardless of eccentricity, which provides support for a general interference account of multitasking. Conclusion The results showed that our gaze-contingent useful field of view paradigm was able to successfully examine older adult multitasking performance in a simulated driving environment. Application This study represents the first attempt to successfully measure dynamic changes in the useful field of view for older adults completing a multitasking scenario involving driving. [ABSTRACT FROM AUTHOR]

Objective: We aimed to develop and test a new dynamic measure of transient changes to the useful field of view (UFOV), utilizing a gaze-contingent paradigm for use in realistic simulated environments.Background: The UFOV, the area from which an observer can extract visual information during a single fixation, has been correlated with driving performance and crash risk. However, some existing measures of the UFOV cannot be used dynamically in realistic simulators, and other UFOV measures involve constant stimuli at fixed locations. We propose a gaze-contingent UFOV measure (the GC-UFOV) that solves the above problems.Methods: Twenty-five participants completed four simulated drives while they concurrently performed an occasional gaze-contingent Gabor orientation discrimination task. Gabors appeared randomly at one of three retinal eccentricities (5°, 10°, or 15°). Cognitive workload was manipulated both with a concurrent auditory working memory task and with driving task difficulty (via presence/absence of lateral wind).Results: Cognitive workload had a detrimental effect on Gabor discrimination accuracy at all three retinal eccentricities. Interestingly, this accuracy cost was equivalent across eccentricities, consistent with previous findings of "general interference" rather than "tunnel vision."Conclusion: The results showed that the GC-UFOV method was able to measure transient changes in UFOV due to cognitive load in a realistic simulated environment.Application: The GC-UFOV paradigm developed and tested in this study is a novel and effective tool for studying transient changes in the UFOV due to cognitive load in the context of complex real-world tasks such as simulated driving. [ABSTRACT FROM AUTHOR]

Objective: A fully immersive, high-fidelity street-crossing simulator was used to examine the effects of texting on pedestrian street-crossing performance.Background: Research suggests that street-crossing performance is impaired when pedestrians engage in cell phone conversations. Less is known about the impact of texting on street-crossing performance.Method: Thirty-two young adults completed three distraction conditions in a simulated street-crossing task: no distraction, phone conversation, and texting. A hands-free headset and a mounted tablet were used to conduct the phone and texting conversations, respectively. Participants moved through the virtual environment via a manual treadmill, allowing them to select crossing gaps and change their gait.Results: During the phone conversation and texting conditions, participants had fewer successful crossings and took longer to initiate crossing. Furthermore, in the texting condition, smaller percentage of time with head orientation toward the tablet, fewer number of head orientations toward the tablet, and greater percentage of total characters typed before initiating crossing predicted greater crossing success.Conclusion: Our results suggest that (a) texting is as unsafe as phone conversations for street-crossing performance and (b) when subjects completed most of the texting task before initiating crossing, they were more likely to make it safely across the street.Application: Sending and receiving text messages negatively impact a range of real-world behaviors. These results may inform personal and policy decisions. [ABSTRACT FROM AUTHOR]

Objective: A high-fidelity street crossing simulator was used to test the hypothesis that experienced action video game players are less vulnerable than non-gamers to dual task costs in complex tasks.Background: Previous research has shown that action video game players outperform nonplayers on many single task measures of perception and attention. It is unclear, however, whether action video game players outperform nonplayers in complex, divided attention tasks.Method: Experienced action video game players and nongamers completed a street crossing task in a high-fidelity simulator. Participants walked on a manual treadmill to cross the street. During some crossings, a cognitively demanding working memory task was added.Results: Dividing attention resulted in more collisions and increased decision making time. Of importance, these dual task costs were equivalent for the action video game players and the nongamers.Conclusion: These results suggest that action video game players are equally susceptible to the costs of dividing attention in a complex task.Application: Perceptual and attentional benefits associated with action video game experience may not translate to performance benefits in complex, real-world tasks. [ABSTRACT FROM AUTHOR]

Objective: A pair of simulated driving experiments studied the effects of cognitive load on drivers' lane-keeping performance.Background: Cognitive load while driving often reduces the variability of lane position. However, there is no agreement as to whether this effect should be interpreted as a performance loss, consistent with other effects of distraction on driving, or as an anomalous performance gain.Method: Participants in a high-fidelity driving simulator performed a lane-keeping task in lateral wind,with instructions to keep a steady lane position. Under high load conditions, participants performed a concurrent working memory task with auditory stimuli. Cross-spectral analysis measured the relationship between wind force and steering inputs.Results: Cognitive load reduced the variability of lane position and increased the coupling between steering wheel position and crosswind strength.Conclusion: Although cognitive load disrupts driver performance in a variety of ways, it produces a performance gain in lane keeping.This effect appears to reflect drivers' efforts to protect lateral control against the risk of distraction, at the apparent neglect of other elements of driving performance.Application: Results may inform educational efforts to help drivers understand the risks of distraction and the inadequacies of compensatory driving strategies. [ABSTRACT FROM AUTHOR]