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The objectives of this research were to (1) explore whether goal-activation models of procedurally based interrupted task performance can be applied to content production, and if not, (2) develop a new theoretical account, and (3) provide support for that theory. Experiment 1 found that interruptions during planning resulted in less developed plans, and that available theoretical models could not account for performance. Experiment 2 leveraged Verbal Protocol Analysis to explore the cognitive mechanisms underlying interrupted task performance on a content production task. We found support for a combination of processes: (1) cues and environmental context, and (2) task activation levels. These results suggested a spreading activation account of interrupted task performance. Experiment 3 provided further support for spreading activation by comparing short and long interruptions. These results have broad implications for moving our understanding of interrupted task performance forward by expanding ou...

As semiautonomous driving systems are becoming prevalent in late model vehicles, it is important to understand how such systems affect driver attention. This study investigated whether measures from low-cost devices monitoring peripheral physiological state were comparable to standard EEG in predicting lapses in attention to system failures. Twenty-five participants were equipped with a low-fidelity eye-tracker and heart rate monitor and with a high-fidelity NuAmps 32-channel quick-gel EEG system and asked to detect the presence of potential system failure while engaged in a fully autonomous lane changing driving task. To encourage participant attention to the road and to assess engagement in the lane changing task, participants were required to: (a) answer questions about that task; and (b) keep a running count of the type and number of billboards presented throughout the driving task. Linear mixed effects analyses were conducted to model the latency of responses reaction time (RT) to automation signals using the physiological metrics and time period. Alpha-band activity at the midline parietal region in conjunction with heart rate variability (HRV) was important in modeling RT over time. Results suggest that current low-fidelity technologies are not sensitive enough by themselves to reliably model RT to critical signals. However, that HRV interacted with EEG to significantly model RT points to the importance of further developing heart rate metrics for use in environments where it is not practical to use EEG.

Modern vehicles can present an ever-changing plethora of information, making it of the utmost importance that signals are evaluated efficiently in the early stages of design. The current study investigates the relationship between traditional methods of physchophysical scaling and newer methods of sorting or categorization. Participants sorted a sample of sounds into “Alarms”, “Status Notifications” and “Social Notifications”. Following the sorting task, participants were asked to rate each individual sound (using a 1-100 scale) on urgency, annoyance and acceptability. Results indicate extremely high correlations between alarm categorization and urgency level where sounds categorized as alarms by more participants were also rated as more urgent by all participants.

Mind wandering is a pervasive threat to transportation safety, potentially accounting for a substantial number of crashes and fatalities. In the current study, mind wandering was induced through completion of the same task for 5 days, consisting of a 20-minute monotonous freeway-driving scenario, a cognitive depletion task, and a repetition of the 20-minute driving scenario driven in the reverse direction. Participants were periodically probed with auditory tones to self-report whether they were mind wandering or focused on the driving task. Self-reported mind wandering frequency was high, and did not statistically change over days of participation. For measures of driving performance, participant labeled periods of mind wandering were associated with reduced speed and reduced lane variability, in comparison to periods of on task performance. For measures of electrophysiology, periods of mind wandering were associated with increased power in the alpha band of the electroencephalogram (EEG), as well as a reduction in the magnitude of the P3a component of the event related potential (ERP) in response to the auditory probe. Results support that mind wandering has an impact on driving performance and the associated change in driver’s attentional state is detectable in underlying brain physiology. Further, results suggest that detecting the internal cognitive state of humans is possible in a continuous task such as automobile driving. Identifying periods of likely mind wandering could serve as a useful research tool for assessment of driver attention, and could potentially lead to future in-vehicle safety countermeasures.

Vibrotactile navigation systems can provide drivers with directional information while reducing annoyance from a voice that interrupts on-going music and conversations. However, little is currently known regarding the working memory processes involved in utilizing vibrotactile navigation. Prior research has demonstrated that individuals differ in their sense of direction and ability to navigate and the working memory resources used to carry out the navigation task. Recent research has shown that vibrotactile cues can be used effectively to facilitate navigation while potentially reducing workload. The aim of this study is to examine impact of vibrotactile navigation systems on working memory. Specifically, the aim is to examine how they may differentially impact individuals based upon their sense of direction. It is predicted that the location based information provided by the vibrotactile navigation system may facilitate performance among individuals with a poor sense of direction – because it is not expected to rely on their verbal working memory. Conversely, vibrotactile systems are expected to hinder the performance of individuals with a good sense of direction since they may overload the visuospatial working memory processes. The results of this research will help in better understanding the differences between these individuals and help improve navigation system design to better navigational performance.

Participants drove a simulated vehicle while completing an n-back task of high or low cognitive demand. Concurrently, they responded via brake press to signals presented in either a single modality (auditory, visual or tactile) or a bimodal combination. Participants were asked to indicate the perceived urgency of each signal by adjusting the force applied in their brake response. Signals were designed to be of “high” or “low” urgency based on previous research for both unimodal and bimodal combinations. Participants were capable of subjectively judging perceived urgency independent of response time and responded to bimodal (relative to unimodal) and high (relative to low) urgency stimuli with significantly greater brake force. However, both factors interacted with cognitive demand indicating that the magnitude of these differential responses was reduced under high demand. Implications for warning evaluation in an in-vehicle driving context are discussed.

Waypoint navigation is a critical task for dismounted soldiers, especially when navigating through novel environments with potential threats. In these dangerous environments, the soldiers should have their “eyes-up” and “ears-out” scanning the environment for critical signals. Current practices for dismounted soldiers include the use of a compass and map or small wearable computer in order to navigate. In this experiment, we compared several modalities and multiple combinations of these modalities in waypoint navigation performance. These modalities include two visual (an egocentric and a geocentric map), 3D spatialized audio, tactile, and the multimodal combinations of each. We also examined individual differences in sense of direction as a potential moderator of display usage. Results provide preliminary evidence that localized 3D audio and haptics navigation aids are an intuitive, efficient, and effective means of waypoint navigation, regardless of sense of direction.

Physiological assessment of cognitive processes has become a topic of increased interest. The value of understanding and measuring brain function at work has the potential to improve performance. The emphasis of this paper is to discuss how pupil diameter can be applied to learning. The link between pupil diameter and task difficulty, or cognitive load, has been repeatedly demonstrated for the past 40 years. However there has been little work to date on measuring cognitive load during training or looking at how real time metrics of cognitive load could be used to adapt training. According to Cognitive Load Theory, cognitive load should be reduced as an individual learns a task and he/she relies more on long term memory than working memory. Ten participants completed a simulated unmanned aerial vehicle task in which they had to identify targets and report their direction of movement. There were three levels of increased difficulty. As expected, pupil diameter significantly dropped within each block as participants learned the task, and then increased again at the start of the next level of difficulty. The results suggest that pupil diameter may be a useful metric for assessing when an individual has transferred information into long term memory. Implications for how pupil diameter can be used to drive an adaptive training system are discussed.

Understanding when operators are experiencing high workload is important in the design and implementation of Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) systems. Fortunately physiological metrics, such as pupillary reflexes, have been shown to correlate with increases in mental workload. This paper proposes an automated method for characterizing and identifying task evoked pupillary responses (TEPR) during various workload levels. This method captures findings and observations from previous TEPR studies in an automated algorithm. This algorithm characterizes the rate of pupil dilation and constriction into a TEPR area metric, which is then used to identify times of increased operator workload. Independent trial analysis shows the benefits of using the TEPR area for distinguishing different workload responses but additional investigation is needed to make the algorithm more robust to individual variability.

Electroencephalography (EEG) has the prospect of providing a means to gauge operator workload in a manner that does not intrude on the task being performed. Specifically, it has been proposed that the technique could be used as a method to speed the learning of a task, by adjusting the task to suit the state of the learner. The present study recorded EEG while participants performed a simulated Unmanned Aerial Vehicle (UAV) reconnaissance task. Analysis of power in three EEG frequency bands of interest found differences between the types of task being performed; however more complex analysis may be necessary to discern levels of difficulty within the task.

Advanced technologies have enabled the choice of either visual or auditory formats for avionics and surface transportation displays. Methods of assessing the mental workload imposed by displays of different formats are critical to their successful implementation. Towards this end a series of investigations were conducted with the following aims: 1) developing analogous auditory and visual versions of a secondary task that could be used to compare display modalities; and 2) to compare the sensitivity of neurophysiological, behavioral and subjective indices of workload. Experiments 1 and 2 confirmed that analogous auditory and visual secondary oddball discrimination tasks were of equivalent difficulty as indicated by P300 amplitude, RT, accuracy and subjective ratings of workload. Experiments 1–3 revealed that RT and accuracy for target detections were generally more sensitive to changes in primary task difficulty than P300 responses and subjective ratings. However, Experiment 3 indicated that P300 amplitude was sensitive to increased perceptual demands (resulting from driving in heavy fog versus clear visibility) not revealed by changes in either behavioral or subjective indices. Together the results of the current investigations indicate that a battery of assessment techniques will provide the most sensitive assessment of workload in complex environments.

Advanced in-vehicle technologies (IVTs) are rapidly being introduced. Methods of assessing the mental workload required by the driving situation are imperative to the safe implementation of these advanced systems. The current investigation compared the sensitivity of an array of assessment techniques to changes in simulated driving task demand. P300 amplitude was sensitive to increased driving task demand due to reduced visibility (presence of fog) but was not sensitive to changes in road type (urban versus freeway). Conversely, RT and accuracy to a secondary task were sensitive to changes in road type but were not sensitive to the visibility manipulation. Subjective workload ratings were not sensitive to either manipulation. Results are discussed in terms of their implications for assessing the impact of environmental factors on the mental workload demands of the driving task and for the design and implementation of adaptive driver interfaces.

The present study investigated the ability of individuals to correctly execute different numbers of commands presented in speech and text format (simulating voice and data link communications). These commands were executed in the presence of different sources of task interference drawing upon visual, verbal, and central executive resources. The results showed that performance decreased as the number of commands in the message set increased from two to four, regardless of presentation format. Visual interference was less disruptive than both verbal and central executive interference. These findings have implications for the design of data link systems and suggest that during periods of high workload, communications should include fewer commands within a message set particularly when there is insufficient time to request clarification.

Despite extensive examination of display parameters affecting written and nonverbal warnings, few investigators have examined presentation parameters affecting auditorially presented verbal warnings. This investigation is the first systematic examination of display parameters affecting verbal warnings that required listeners to be engaged in a contextually appropriate simultaneous task. Participants responded to verbal collision avoidance system (CAS) messages while engaged in a simultaneous simulated driving task. Perceived urgency, alerting effectiveness and annoyance ratings and behavioral reaction times were examined as a function of the signal word, CAS message, and presentation level (PL). Consistent with predictions from previous research involving written warnings, differences in the perceived urgency were observed as a function of the signal word used. PL also significantly impacted perceived urgency and alerting effectiveness. CAS messages presented at a S/N ratio of at least +4 dB resulted in high ratings of perceived urgency ratings and were responded too relatively quickly without a substantial tradeoff in increased annoyance ratings.

Recent empirical evidence underscoring the necessity of considering the role hearing abilities when using auditory tasks to assess age-related changes in cognitive abilities is presented. Young participants, screened for hearing impairment, were required to perform a simulated driving task concurrently with an auditory task in which stimuli were presented at intensity levels simulating age-related hearing impairment. Young participants demonstrated performance decrements mirroring those of older participants in a separate but similar dual task investigation. In conjunction with evidence found by previous researchers, the results presented here provide clear evidence for the need to utilize methodologies that account for age-related hearing deficit when using auditory tasks as indices of cognitive abilities with older adults.

Verbal warnings are designed to alert as well as provide information to an operator who is likely to be performing several simultaneous tasks. Yet, research generally ignores the potential of presentation intensity to alter the attentional demands placed on the operator by verbal warnings in multi-task environments. Results of the current investigation demonstrate that as the presentation intensity of speech stimuli decreased from 70 to 50 dB, participants made more auditory processing errors, but only when required to perform a simultaneous simulated driving task. Auditory task performance did not differ significantly between conditions in single task trials. However, as signal presentation level decreased, participants made significantly more incorrect responses in both an auditory mental arithmetic task and a sentence processing task while driving performance remained unchanged. Results are discussed in terms of their implications for the design of verbal displays and warnings for use in transportation settings particularly with older, hearing impaired listeners.

Recent work has identified an event-related potential (ERP) component, the incongruency negativity (Ninc), which is sensitive to auditory Stroop conflict processing. Here, we investigated how this index of conflict processing is influenced by individual differences in cognitive style. There is evidence that individuals differ in the strategy they use to navigate through the environment; some use a predominantly verbal-egocentric strategy while others rely more heavily on a spatial-allocentric strategy. In addition, navigational strategy, assessed by a way-finding questionnaire, is predictive of performance on an auditory spatial Stroop task, in which either the semantic or spatial dimension of stimuli must be ignored. To explore the influence of individual differences in navigational style on conflict processing, participants took part in an auditory spatial Stroop task while the electroencephalogram (EEG) was recorded. Whereas behavioral performance only showed a main effect of congruency, we observed the predicted three-way interaction between congruency, task type and navigational style with respect to our physiological measure of Stroop conflict. Specifically, congruency-dependent modulation of the Ninc was observed only when participants performed their non-dominant task (e.g., verbal navigators attempting to ignore semantic information). These results confirm that the Ninc reliably indexes auditory Stroop conflict and extend previous results by demonstrating that the Ninc is predictably modulated by individual differences in cognitive style.

Twenty-two participants drove a simulated vehicle while engaged in a low or high working memory load task and responded to signals presented in auditory, visual and tactile modalities or their bimodal combinations by pressing on the brake. Signals were designed to be of low or high urgency in both unimodal and bimodal combinations. High urgency and bimodal signals were responded to faster than their low urgency and unimodal counterparts. Fewer bimodal signals were missed overall. This bimodal advantage was particularly significant relative to unimodal signals of low urgency in the high working memory load condition. Together these results indicate that hazard mapping can most effectively be obtained by designing with both the perceived urgency level of the signal and modal plurality in mind.

Older drivers constitute the fastest growing segment of the driving population, in terms of both number of drivers and number of miles driven. Accident analyses reveal that older drivers are not able to fully compensate for emerging reductions in perceptual/cognitive capacity. Establishment of a method of assessing older drivers with perceptual/cognitive impairments which place them at risk of accidents is imperative. In this investigation, a subsidiary task of mental arithmetic was demonstrated to be sensitive to age differences in relative mental workload resulting from increased steering task complexity in a simulated driving task. As steering task difficulty increased, verbal response latency to concurrent mental arithmetic problems increased for older, but not younger, participants. Steering error remained stable across single and dual task conditions indicating that the secondary mental arithmetic task did not interfere with steering (primary task) performance. These results provide preliminary support for the use of this assessment technique outside of the laboratory in actual driving situations.

Mind wandering while performing various tasks has been shown to increase errors and impair task performance (Smallwood, McSpadden, & Schooler, 2008). Performance decrements elicited by mind wandering occur when attention necessary for the primary task is diverted to task-unrelated thoughts. While these results remain consistent in various domains, it is less understood how driving performance is affected by mind wandering. He Becic, Lee, and McCarley (2011) used a self-caught method to detect mind wandering, finding that variability in vehicle velocity decreased during states of mind wandering compared to attentive states. Other studies using a probe method to detect mind wandering have found that speed was greater during mind wandering (Yanko & Spalek, 2014), or that speed and speed variability were lower during mind wandering (Bencich, Gamboz, Coluccia, & Brandimonte, 2014) compared to attentive states. Although these studies provide some insight about the performance decrements and associated consequences of engaging in mind wandering while driving, the extent that mind wandering affects driving performance is not fully understood. The goal for this research was to further investigate differences in driving performance during mind wandering and attentive states. Participants performed two simulated driving scenarios and were instructed to indicate when they noticed they were just mind wandering (He et al., 2011; Smallwood & Schooler, 2015) by pressing a button on the steering wheel. Episodes of mind wandering were classified as 10 seconds before a button press with a three second buffer and, for comparison, instances of attentiveness relative to mind wandering episodes were classified as 10 seconds after a button press with a three second buffer (He et al., 2011). The results from linear mixed effects models showed that steering reversal rate, lane deviation, and lateral position were significantly greater during attentive states compared to states of mind wandering. These results may best be explained by Michon’s (1985) proposal that driving is a hierarchical task consisting of three levels. The first level includes basic operational control (e.g., speed and lane maintenance), while the higher-order levels are tactical (e.g., interacting with other vehicles, lane changing, etc.) and strategic (e.g., navigation, planning, and decision making). Our data suggest that mind wandering affected but did not necessarily disrupt driving performance. However, the present study only investigated basic operational-level metrics. Mind wandering may be more likely to negatively influence the detection of critical events and hazards–deviations from routine behaviors associated with higher level components of the driving task (i.e., tactical and strategic). For example, Yanko and Spalek (2014) reported that when participants were mind wandering they responded more slowly to critical events while driving. Further research is needed to determine whether the negative effects of mind wandering are more likely to occur within these higher order components of the driving tasks.

Adaptive training using neurophysiological measures requires efficient classification of mental workload in real time as a learner encounters new and increasingly difficult levels of tasks. Previous investigations have shown that artificial neural networks (ANNs) can accurately classify workload, but only when trained on neurophysiological exemplars from experienced operators on specific tasks. The present study examined classification accuracies for ANNs trained on electroencephalographic (EEG) activity recorded while participants performed the same (within task) and different (cross) tasks for short periods of time with little or no prior exposure to the tasks. Participants performed three working memory tasks at two difficulty levels with order of task and difficulty level counterbalanced. Within-task classification accuracies were high when ANNs were trained on exemplars from the same task or a set containing the to-be-classified task, (M = 87.1% and 85.3%, respectively). Cross-task classification accuracies were significantly lower (average 44.8%) indicating consistent systematic misclassification for certain tasks in some individuals. Results are discussed in terms of their implications for developing neurophysiologically driven adaptive training platforms.

There have been a number of successes of real-time application of physiological measures in operational environments such as with the control of remotely piloted vehicles (RPV). More recently, similar techniques have been investigated within the context of improving learning. A major challenge of the learning environment is that an individual's ability to perform the task, and thus their workload experienced during the task, are constantly changing. Cognitive Load Theory provides insight into how workload interacts with learning. One aspect of this theory is that as information is learned it reduces working memory demands. This paper discusses results from an RPV training study investigating the effects of workload and learning on pupil diameter. Specifically, pupil diameter decreased overtime as the task difficulty was held constant, and increased as new information was presented. The results of these studies are discussed in terms of how they can be used in a physiologically driven adaptive training system.

Objective: The current investigation examined individual differences in route-learning strategies and their relative demands on visuospatial versus verbal working memory (WM) resources in virtual environments. Background: Learning new routes is a resource-demanding activity that must often be carried out in conjunction with other concurrent tasks. Virtual environments (VEs) are increasingly being used for training and research, pointing to the importance of determining the strategies people use to learn routes in these environments. Methods: Participants classified as having good or poor sense of direction (SOD) attempted to learn novel routes while concurrently performing either a verbal (articulatory suppression) or a visuospatial (tapping) WM interference task. Results: Different navigational strategies were observed in each SOD group. Individuals with poor SOD relied more heavily on verbal rather than visuospatial WM resources, as evidenced by greater disruption to route-learning performance from the articulatory suppression task relative to the tapping task. Conversely, individuals with good SOD exhibited more route-learning disruption from the tapping task, suggesting a greater reliance on visuospatial WM resources. Conclusion: Individuals differ from one another in the strategies they use and the WM resources they tap—verbal or visuospatial—to learn routes in VEs. Self-report measures can be used as indices of such individual differences in navigational strategy use in VE tasks. Application: Assessing SOD and associated WM resources have implications for targeted training for navigation in VEs and for the design of in-vehicle navigation systems.

High traffic density can be expected to increase the attentional processing requirements of driving. Establishing methods of assessing the differential demands placed on drivers by environmental variables has been the focus of a recent series of investigations. Results of an initial examination of the impact of traffic density on mental workload are reported here. The current investigation utilizes an array of methodological assessment techniques and compares the sensitivity of each to changes in attentional processing requirements as a function of driving task demand. Analogous versions of a visual and auditory sensory detection task were developed and used in a dual task paradigm involving simulated driving. P300 amplitude, though in the predicted direction, failed to distinguish between increased task demands resulting from increases in traffic density. Response time and accuracy to the detection task in both visual and auditory modalities demonstrated significant processing decrements as a function of increased traffic density. Subjective workload ratings obtained from the NASA TLX did not distinguish between driving task difficulty, but indicated that performing the visual detection task in combination with driving was perceived as more difficult than performing the concurrent auditory task. Implications of these results for modeling differential aspects of mental workload and for establishing workload assessment techniques for surface transportation environments are discussed.

Speech displays and verbal response technologies are increasingly being used in complex, high workload environments that require the simultaneous performance of visual and manual tasks. Examples of such environments include the flight decks of modern aircraft, advanced transport telematics systems providing invehicle route guidance and navigational information and mobile communication equipment in emergency and public safety vehicles. Previous research has established an optimum range for speech intelligibility. However, the potential for variations in presentation levels within this range to affect attentional resources and cognitive processing of speech material has not been examined previously. Results of the current experimental investigation demonstrate that as presentation level increases within this 'optimum' range, participants in high workload situations make fewer sentence-processing errors and generally respond faster. Processing errors were more sensitive to changes in presentation level than were measures of reaction time. Implications of these findings are discussed in terms of their application for the design of speech communications displays in complex multi-task environments.

Previous empirical research has demonstrated that even within clearly audible ranges (45-70 dB with less than 35 dB background noise), people tend to make more errors and take longer to respond to even simple auditory tasks as the presentation level of auditory stimuli decreases when attentional processing requirements are high (Baldwin, 1997, Baldwin, Struckman-Johnson, Galinsky, & Williams, 1999). The observed decrease in performance with decreasing decibel level may be due to shorter echoic memory traces, which could exacerbate demands on attentional resources during periods of high mental workload. In order to examine this hypothesis, participants were asked to listen to sets of tones and verbally indicate whether the second pattern in each set matched the first pattern while simultaneously performing a loading task involving simulated driving. Tonal sets varied according to the decibel level of presentation (60, 65, & 70 dB) and the delay period between presentation of the first tonal pattern and presentation of the second comparison pattern (2 s, 3 s, or 4 s). As predicted, a significant interaction between delay time and presentation level was observed with participants making more errors and requiring greater time to respond in the 4 s delay condition, particularly in the lower 60 dB presentation level condition. Population aging and associated increases in the incidence of hearing loss are occurring at a time when verbal displays are increasingly being used in complex environments. Additionally, the need for persons of diverse language backgrounds to communicate in occupational environments with less than optimum acoustical environments make design accommodations that facilitate cognitive processing of speech in complex systems imperative. Slight increases in presentation level may be one way to facilitate the communication process by increasing the duration during which verbal material may be accessed for processing.