David Strayer
University of Utah, Psychology, Faculty Member
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We address several themes that emerged in the commentaries related to our target article. First, we consider the relationship between cognitive distraction and crash risk. Second, we discuss the development of our cognitive distraction... more
We address several themes that emerged in the commentaries related to our target article. First, we consider the relationship between cognitive distraction and crash risk. Second, we discuss the development of our cognitive distraction scale. Third, we weigh issues of self-regulation, appropriate baselines, and satisficing. Finally, we identify several areas where additional research is needed to refine our understanding of driver distraction and crash risk.
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The effects of distraction on responses manifest in three ways: prolonged reaction times, and increased error and response omission rates. However, the latter effect is often ignored or assumed to be due to a separate cognitive process.... more
The effects of distraction on responses manifest in three ways: prolonged reaction times, and increased error and response omission rates. However, the latter effect is often ignored or assumed to be due to a separate cognitive process. We investigated omissions occurring in two paradigms that manipulated distraction. One required simple stimulus detection of younger participants, the second required choice responses and was completed by both younger and older participants. We fit data from these paradigms with a model that identifies three causes of omissions: two are related to the process of accumulating the evidence on which a response is based: intrinsic omissions (due to between-trial variation in accumulation rates making it impossible to ever reach the evidence threshold) and design omissions (due to response windows that cause slow responses not to be recorded; a third, contaminant omissions, allows for a cause unrelated to the response process. In both data sets systematic differences in omission rates across conditions were accounted for by task-related omissions. Intrinsic omissions played a lesser role than design omissions, even though the presence of design omissions was not evident in descriptive analyses of the data. The model provided an accurate account of all aspects of the detection data and the choice-response data, but slightly underestimated overall omissions in the choice paradigm, particularly in older participants, suggesting that further investigation of contaminant omission effects is needed.
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IntroductionPartial driving automation is not always reliable and requires that drivers maintain readiness to take over control and manually operate the vehicle. Little is known about differences in drivers’ arousal and cognitive demands... more
IntroductionPartial driving automation is not always reliable and requires that drivers maintain readiness to take over control and manually operate the vehicle. Little is known about differences in drivers’ arousal and cognitive demands under partial automation and how it may make it difficult for drivers to transition from automated to manual modes. This research examined whether there are differences in drivers’ arousal and cognitive demands during manual versus partial automation driving.MethodWe compared arousal (using heart rate) and cognitive demands (using the root mean square of successive differences in normal heartbeats; RMSSD, and Detection Response Task; DRT) while 39 younger (M= 28.82 years) and 32 late-middle-aged (M= 52.72 years) participants drove four partially automated vehicles (Cadillac, Nissan Rogue, Tesla, and Volvo) on interstate highways. If compared to manual driving, drivers’ arousal and cognitive demands were different under partial automation, then corre...
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Objective This research explores the effect of partial vehicle automation on neural indices of mental workload and visual engagement during on-road driving. Background There is concern that the introduction of automated technology in... more
Objective This research explores the effect of partial vehicle automation on neural indices of mental workload and visual engagement during on-road driving. Background There is concern that the introduction of automated technology in vehicles may lead to low driver stimulation and subsequent disengagement from the driving environment. Simulator-based studies have examined the effect of automation on a driver’s cognitive state, but it is unknown how the conclusions translate to on-road driving. Electroencephalographic (EEG) measures of frontal theta and parietal alpha can provide insight into a driver’s mental workload and visual engagement while driving under various conditions. Method EEG was recorded from 71 participants while driving on the roadway. We examined two age cohorts, on two different highway configurations, in four different vehicles, with partial vehicle automation both engaged and disengaged. Results Analysis of frontal theta and parietal alpha power revealed that th...
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The features of vehicle-based infotainment technology have greatly expanded in recent years, opening up a new array of tasks accessible to motorists while driving. Many of these new functions are unrelated to driving. Examples include... more
The features of vehicle-based infotainment technology have greatly expanded in recent years, opening up a new array of tasks accessible to motorists while driving. Many of these new functions are unrelated to driving. Examples include voice commands to send a text message, check social media or surf the web. Furthermore, many tasks distract motorists from driving by diverting their eyes and attention from the road and hands from the steering wheel. Yet, surprisingly, little is known about how these interactions may affect a driver’s performance when the demands are high.
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Human operators often experience large fluctuations in cognitive workload that can lead to sub-optimal performance, ranging from overload to neglect. Help from automated support systems could potentially address this issue, but to do so... more
Human operators often experience large fluctuations in cognitive workload that can lead to sub-optimal performance, ranging from overload to neglect. Help from automated support systems could potentially address this issue, but to do so the system would ideally need to be aware of real-time changes in operators’ cognitive workload, so it can provide help in times of peak demand and take advantage of troughs to elicit operator engagement. We used the ISO standard Detection Response Task (DRT) to measure cognitive workload approximately every 4 seconds in a demanding task requiring monitoring and refuelling of a fleet of unmanned aerial vehicles (UAVs). We showed that the DRT provided a valid measure that can detect changes in workload due to changes in the number of UAVs. We used a cross-validation analysis to assess whether measures related to task performance immediately preceding the DRT could be used to predict detection performance as a proxy for cognitive workload. Although the...
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Objective: A set of 4 driving related tasks were used to evaluate the potential for a modified Detection Response Task (DRT) to simultaneously measure visual and cognitive task demands. Background: The accurate assessment of cognitive and... more
Objective: A set of 4 driving related tasks were used to evaluate the potential for a modified Detection Response Task (DRT) to simultaneously measure visual and cognitive task demands. Background: The accurate assessment of cognitive and visual tasks demands in driving has become increasingly important. As of yet, no simple, cost effective approach has been found to measure visual demands in complex, multimodal tasks. Methods: Two experiments are presented which evaluate an extension of the standard DRT methodology. The discriminate sensitivity of the experiments is tested using an integrated testing configuration, which systematically increased visual demand across four conditions. Results: Results suggest that the standard DRT configurations are highly tuned to selectively evaluate cognitive demand but that a variant of the system may be able to simultaneously evaluate changes in both visual and cognitive task demands. Conclusions: These data suggest that the simple, rapid, and r...
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With the emergence of vehicle-based technologies that could compete for attention due to visual and cognitive workloads in a driving environment, it is important to accurately assess the various components of potential distractions.... more
With the emergence of vehicle-based technologies that could compete for attention due to visual and cognitive workloads in a driving environment, it is important to accurately assess the various components of potential distractions. Current Detection Response Task (DRT) measurements are sensitive to overall mental workload, but may not be useful for assessing visual workload. This study seeks to examine the ability of two unique extensions of DRTs to assess levels of cognitive and visual load in a lateral steering tracking task. Each DRT was tested in conditions that manipulated cognitive load, visual load, the combination of cognitive and visual load, and normal driving conditions. The data suggest that an altered design of the DRT may allow for reliable assessment of cognitive and visual loads simultaneously during a driving task. Measuring the components of different types of workload that lead to driver distraction may inform industry standards for assessing driver distraction i...
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The Detection Response Task (DRT) is an international standard for assessing workload that has minimal effects on primary task performance, making it an attractive option for workload measurement in many settings. An increase in DRT... more
The Detection Response Task (DRT) is an international standard for assessing workload that has minimal effects on primary task performance, making it an attractive option for workload measurement in many settings. An increase in DRT response times and a decrease hit rates as primary task load increases is thought to occur due to competing resources being reallocated to the primary task. However, alternative processes could account for these effects, including changes in response caution, response bias and non-decision processes. We examine how people respond to changes in task demands in a dual-task environment and aim to identify what it is that the DRT is measuring. We model a primary classification task and the DRT in a time pressured environment using the linear ballistic accumulator (Brown & Heathcote, 2008) and a single-bound diffusion (Wald) model (Heathcote, 2004). Under greater time pressure, the rate of information processing increased on the primary task while response ca...
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The N-back and Surrogate Reference Task (SuRT) are frequently used to evaluate the workload potential of secondary driving tasks as high cognitive and visual demand benchmarks. This paper examines the effect of repeated exposures to the... more
The N-back and Surrogate Reference Task (SuRT) are frequently used to evaluate the workload potential of secondary driving tasks as high cognitive and visual demand benchmarks. This paper examines the effect of repeated exposures to the N-back and SuRT reference tasks, and any resulting change in task performance or workload that may negate their effectiveness as calibration tools and high workload benchmarks. One-way repeated measures ANOVA analyses demonstrate that N-back performance improves while workload decreases, suggesting limitations in methodology for measuring task workload after multiple exposures. Alternatively, SuRT performance improves while workload remains relatively stable, indicating the task elicits a constant visual demand despite performance improvements. This paper discusses the limitations of the N-back and SuRT as reference tasks in workload and driving research, and proposes future directions to further clarify their use.
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Cognitive load from secondary tasks is a source of distraction causing injuries and fatalities on the roadway. The Detection Response Task (DRT) is an international standard for assessing cognitive load on drivers' attention that can... more
Cognitive load from secondary tasks is a source of distraction causing injuries and fatalities on the roadway. The Detection Response Task (DRT) is an international standard for assessing cognitive load on drivers' attention that can be performed as a secondary task with little to no measurable effect on the primary driving task. We investigated whether decrements in DRT performance were related to the rate of information processing, levels of response caution, or the non-decision processing of drivers. We had pairs of participants take part in the DRT while performing a simulated driving task, manipulated cognitive load via the conversation between driver and passenger, and observed associated slowing in DRT response time. Fits of the single-bound diffusion model indicated that slowing was mediated by an increase in response caution. We propose the novel hypothesis that, rather than the DRT's sensitivity to cognitive load being a direct result of a loss of information proce...
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The auto industry’s headlong rush to keep drivers connected by means of speech interfaces seems to have the blessing of NHTSA, the U.S. National Highway Traffic Safety Administration. While NHTSA’s distraction guidelines rightly warn... more
The auto industry’s headlong rush to keep drivers connected by means of speech interfaces seems to have the blessing of NHTSA, the U.S. National Highway Traffic Safety Administration. While NHTSA’s distraction guidelines rightly warn against visual and manual distraction, they advise that “many of these in-vehicle device tasks [not related to driving] may be suitable for performance by the driver while driving, if performed via an auditory-vocal interface.” However, NHTSA’s position is diametrically opposed to the findings of the AAA (American Automobile Association) Foundation for Automotive Safety’s authoritative new study, Measuring Cognitive Distraction in the Automobile, published in June 2013. The study concludes that “the adoption of voice-based systems in the vehicle may have unintended consequences that adversely affect traffic safety.” According to the AAA press release: Hands-free technologies might make it easier for motorists to text, talk on the phone, or even use Face...
Human operators often experience large fluctuations in cognitive workload over seconds timescales that can lead to sub-optimal performance, ranging from overload to neglect. Adaptive automation could potentially address this issue, but to... more
Human operators often experience large fluctuations in cognitive workload over seconds timescales that can lead to sub-optimal performance, ranging from overload to neglect. Adaptive automation could potentially address this issue, but to do so it needs to be aware of real-time changes in operators’ spare cognitive capacity, so it can provide help in times of peak demand and take advantage of troughs to elicit operator engagement. However, it is unclear whether rapid changes in task demands are reflected in similarly rapid fluctuations in spare capacity, and if so what aspects of responses to those demands are predictive of the current level of spare capacity. We used the ISO standard detection response task (DRT) to measure cognitive workload approximately every 4 s in a demanding task requiring monitoring and refueling of a fleet of simulated unmanned aerial vehicles (UAVs). We showed that the DRT provided a valid measure that can detect differences in workload due to changes in t...
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The efficacy of two methods of training dual-task skills was examined in this experiment. Thirty older subjects (Mean age = 67.8 years) were trained using either variable priority or fixed priority training. Subjects performed two tasks,... more
The efficacy of two methods of training dual-task skills was examined in this experiment. Thirty older subjects (Mean age = 67.8 years) were trained using either variable priority or fixed priority training. Subjects performed two tasks, a gauge monitoring task and a letter arithmetic task, both separately and together. Subjects in the variable priority group were trained to vary their processing priorities between the letter arithmetic and monitoring tasks. The fixed priority subjects were trained to devote equal priority to the two tasks. Subjects then transferred to a complex scheduling task which was paired with a paired-associates task. Variable priority subjects exhibited an initial performance cost relative to fixed priority subjects. By the end of training, however, variable priority subjects exhibited superior performance as compared to fixed priority subjects. The performance of variable priority subjects was also superior on transfer tasks with which the subjects had no p...
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Dual-task studies assessed the effects of cellular-phone conversations on performance of a simulated driving task. Performance was not disrupted by listening to radio broadcasts or listening to a book on tape. Nor was it disrupted by a... more
Dual-task studies assessed the effects of cellular-phone conversations on performance of a simulated driving task. Performance was not disrupted by listening to radio broadcasts or listening to a book on tape. Nor was it disrupted by a continuous shadowing task using a handheld phone, ruling out, in this case, dual-task interpretations associated with holding the phone, listening, or speaking. However, significant interference was observed in a word-generation variant of the shadowing task, and this deficit increased with the difficulty of driving. Moreover, unconstrained conversations using either a handheld or a hands-free cell phone resulted in a twofold increase in the failure to detect simulated traffic signals and slower reactions to those signals that were detected. We suggest that cellular-phone use disrupts performance by diverting attention to an engaging cognitive context other than the one immediately associated with driving.
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The goal of this research was to examine the impact of voice-based interactions using 3 different intelligent personal assistants (Apple's Siri, Google's Google Now for Android phones, and Microsoft's Cortana) on the cognitive... more
The goal of this research was to examine the impact of voice-based interactions using 3 different intelligent personal assistants (Apple's Siri, Google's Google Now for Android phones, and Microsoft's Cortana) on the cognitive workload of the driver. In 2 experiments using an instrumented vehicle on suburban roadways, we measured the cognitive workload of drivers when they used the voice-based features of each smartphone to place a call, select music, or send text messages. Cognitive workload was derived from primary task performance through video analysis, secondary-task performance using the Detection Response Task (DRT), and subjective mental workload. We found that workload was significantly higher than that measured in the single-task drive. There were also systematic differences between the smartphones: The Google system placed lower cognitive demands on the driver than the Apple and Microsoft systems, which did not differ. Video analysis revealed that the differen...
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The use of cell phones while driving is ubiquitous, particularly in countries where the practice is legal. However, surveys indicate that most drivers favor legislation to limit the use of mobile devices during the operation of a vehicle.... more
The use of cell phones while driving is ubiquitous, particularly in countries where the practice is legal. However, surveys indicate that most drivers favor legislation to limit the use of mobile devices during the operation of a vehicle. A study was conducted to understand this inconsistency between what drivers do and what they advocate for others. Participants completed a survey about their driving attitudes, abilities, and behaviors. Following previous research, drivers reported using cell phones for benefits such as getting work done. The hypocrisy of using cell phones while advocating restrictions appears to stem from differences in the perceived safety risks of self vs. others' use of cell phones. Many if not most drivers believe they can drive safely while using mobile devices. However, they lack confidence in others' ability to drive safely while distracted and believe that others' use of cell phones is dangerous. The threat to public safety of others' usage...
Research Interests: Business, Engineering, Cell Phones, Computer Security, Adolescent, and 15 moreMedicine, Pergamon, Humans, Legislation, Female, Male, Occupational Safety and Health, Attitude, Human Factors and Ergonomics, Adult, Accident analysis and prevention, Internet privacy, Phone, Distracted Driving, and Automobile driving
The objective was to identify key cognitive processes that are impaired when drivers divert attention from driving. Driver distraction is increasingly recognized as a significant source of injuries and fatalities on the roadway. A... more
The objective was to identify key cognitive processes that are impaired when drivers divert attention from driving. Driver distraction is increasingly recognized as a significant source of injuries and fatalities on the roadway. A "SPIDER" model is developed that identifies key cognitive processes that are impaired when drivers divert attention from driving. SPIDER is an acronym standing for scanning, predicting, identifying, decision making, and executing a response. When drivers engage in secondary activities unrelated to the task of driving, SPIDER-related processes are impaired, situation awareness is degraded, and the ability to safely operate a motor vehicle may be compromised. The pattern of interference helps to illuminate the sources of driver distraction and may help guide the integration of new technology into the automobile.
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The objective was to establish a systematic framework for measuring and understanding cognitive distraction in the automobile. Driver distraction from secondary in-vehicle activities is increasingly recognized as a significant source of... more
The objective was to establish a systematic framework for measuring and understanding cognitive distraction in the automobile. Driver distraction from secondary in-vehicle activities is increasingly recognized as a significant source of injuries and fatalities on the roadway. Across three studies, participants completed eight in-vehicle tasks commonly performed by the driver of an automobile. Primary, secondary, subjective, and physiological measures were collected and integrated into a cognitive distraction scale. In-vehicle activities, such as listening to the radio or an audio book, were associated with a low level of cognitive workload; the conversation activities of talking to a passenger in the vehicle or conversing with a friend on a handheld or hands-free cell phone were associated with a moderate level of cognitive workload; and using a speech-to-text interfaced e-mail system involved a high level of cognitive workload. The research established that there are significant im...
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Multitasking diminishes the self-awareness of performance that is often essential for self-regulation and self-knowledge. Participants drove in a simulator while either talking or not talking on a hands-free cell phone. Following previous... more
Multitasking diminishes the self-awareness of performance that is often essential for self-regulation and self-knowledge. Participants drove in a simulator while either talking or not talking on a hands-free cell phone. Following previous research, participants who talked on a cell phone made more serious driving errors than control participants who did not use a phone while driving. Control participants' assessments of the safeness of their driving and general ability to drive safely while distracted were negatively correlated with the actual number of errors made when they were driving. By contrast, cell-phone participants' assessments of the safeness of their driving and confidence in their driving abilities were uncorrelated with their actual errors. Thus, talking on a cell phone not only diminished the safeness of participants' driving, it diminished their awareness of the safeness of their driving.
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SummaryStereotypes can harm human performance, especially when activated in individuals with diminished working memory capacity (WMC). Performance implications for the stereotype of poor driving in older adults were investigated. Using a... more
SummaryStereotypes can harm human performance, especially when activated in individuals with diminished working memory capacity (WMC). Performance implications for the stereotype of poor driving in older adults were investigated. Using a sample of older adults, WMC (the ability to maintain task goals and ignore distractions) and driving performance [brake reaction time (RT), following distance, and crashes] were assessed, the latter using a high‐fidelity simulator. Elderly participants under stereotype threat with reduced WMC exhibited slower brake RTs and longer following distances compared with a control condition that was not threatened. This driving profile was characteristic of cognitive distraction. Stereotype threat has clear consequences for human performance in a common real‐world task—driving—that is critical to public safety. Furthermore, these findings suggest caution in how the media and public policy communicate information about older adult driving.Copyright © 2015 Jo...
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Research Interests: Psychology, Cognitive Psychology, Cognitive Science, Quantitative Psychology, Attention, and 15 moreWorking Memory, Medicine, Executive Function, Experimental Analysis of Behavior, Humans, Multitasking, Female, Male, Social and Behavioral Sciences, Adult, N back, Neurosciences, Proactive Interference, Systems Factorial Technology, and Psychomotor Performance
In this article we develop a model of the relationship between crash risk and a driver's situation awareness. We consider a driver's situation awareness to reflect the dynamic mental model of the driving environment and to be... more
In this article we develop a model of the relationship between crash risk and a driver's situation awareness. We consider a driver's situation awareness to reflect the dynamic mental model of the driving environment and to be dependent upon several psychological processes including Scanning the driving environment, Predicting and anticipating hazards, Identifying potential hazards in the driving scene as they occur, Deciding on an action, and Executing an appropriate Response (SPIDER). Together, SPIDER is important for establishing and maintaining good situation awareness of the driving environment and good situation awareness is important for coordinating and scheduling the SPIDER-relevant processes necessary for safe driving. An Order-of-Processing (OP) model makes explicit the SPIDER-relevant processes and how they predict the likelihood of a crash when the driver is or is not distracted by a secondary task. For example, the OP model shows how a small decrease in the like...
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Multi-tasking is now ubiquitous component of our lives; despite the fact that we all can cite an incident where multi-tasking put us in a difficult situation. The reason so many of us do multi-task is that most of the time we are capable... more
Multi-tasking is now ubiquitous component of our lives; despite the fact that we all can cite an incident where multi-tasking put us in a difficult situation. The reason so many of us do multi-task is that most of the time we are capable of effective dual task performance. Hart and Wickens (2008) have defined the point where one traverses safe and effective multi-tasking to dangerous and ineffective multi-tasking as the “red-line” of workload. In this panel, we will discuss this “red-line” of workload from the theoretical, empirical, and practical viewpoints. To that end, we first examine what theories of attention can help guide empiric search for this red line and where these theories must be expanded with further research. The greatest need is research that will allow human factors practitioners to identify the red line of workload before a system has been developed. One approach to achieving this research is to leverage the approach of industrial ergonomics, which has successfully defined physical workload limits by using data from safety incidents. Another avenue of research to be discussed is that which will lead to refinement of our theories and understanding of cognitive function to improve our ability to predict the red line. Next we move to the problem of evaluating systems to ensure that the red line of workload is not crossed. In particular, we will discuss the possibility of using task analysis, specifically, CPM-GOMS to predict if a system design will lead to excessive workload. Finally, we present two system design strategies for maintaining a cognitive workload that is below the red-line. The first of these is an adaptive automation using eye-tracking to reduce screen clutter when it appears workload has become so high an error may occur. The second design strategy presents four research based design principles for reducing workload to acceptable levels.