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Our research examined the effects of hands-free cell phone conversations on simulated driving. We found that driving performance of both younger and older adults was influenced by cell phone conversations. Compared with single-task (i.e., driving-only) conditions, when drivers used cell phones their reactions were 18% slower, their following distance was 12% greater, and they took 17% longer to recover the speed that was lost following braking. There was also a twofold increase in the number of rear-end collisions when drivers were conversing on a cell phone. These cell-phone-induced effects were equivalent for younger and older adults, suggesting that older adults do not suffer a significantly greater penalty for talking on a cell phone while driving than compared with their younger counterparts. Interestingly, the net effect of having younger drivers converse on a cell phone was to make their average reactions equivalent to those of older drivers who were not using a cell phone. Actual or potential applications of this research include providing guidance for recommendations and regulations concerning the use of mobile technology while driving.

Objective: The objective was to identify key cognitive processes that are impaired when drivers divert attention from driving. Background: Driver distraction is increasingly recognized as a significant source of injuries and fatalities on the roadway. Method/Results: 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. Conclusion: 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. Application: The pattern of interference helps to illuminate the sources of driver distraction and may help guide the integration of new technology into the automobile.

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.

Objective: Our research examined the effects of practice on cell-phone—related driver distraction. Background: The driving literature is ambiguous as to whether practice can reduce driver distraction from concurrent cell phone conversation. Methods: Drivers reporting either high or low real-world cell phone usage were selected to participate in four 90-min simulated driving sessions on successive days. The research consisted of two phases: a practice phase and a novel transfer phase. Results: Dual-task performance deficits persisted through practice and transfer driving conditions. Moreover, groups reporting high and low real-world experience exhibited similar driving impairments when conversing on a hands-free cell phone. Conclusions: These data indicate that practice is unlikely to eliminate the disruptive effects of concurrent cell phone use on driving. Application: Multiple regulatory agencies have considered, or are currently considering, legislation to restrict in-vehicle cell phone use. Findings reported herein may be useful to inform these public policy decisions.

Objective: The objective of this research was to determine the relative impairment associated with conversing on a cellular telephone while driving. Background: Epidemiological evidence suggests that the relative risk of being in a traffic accident while using a cell phone is similar to the hazard associated with driving with a blood alcohol level at the legal limit. The purpose of this research was to provide a direct comparison of the driving performance of a cell phone driver and a drunk driver in a controlled laboratory setting. Method: We used a high-fidelity driving simulator to compare the performance of cell phone drivers with drivers who were intoxicated from ethanol (i.e., blood alcohol concentration at 0.08% weight/volume). Results: When drivers were conversing on either a handheld or hands-free cell phone, their braking reactions were delayed and they were involved in more traffic accidents than when they were not conversing on a cell phone. By contrast, when drivers were intoxicated from ethanol they exhibited a more aggressive driving style, following closer to the vehicle immediately in front of them and applying more force while braking. Conclusion: When driving conditions and time on task were controlled for, the impairments associated with using a cell phone while driving can be as profound as those associated with driving while drunk. Application: This research may help to provide guidance for regulation addressing driver distraction caused by cell phone conversations.

Intro -- Fundamentals of Ecosystem Science -- Copyright -- Contents -- Contributors -- Preamble to the 2nd Edition -- Preface -- Section I: Introduction -- Chapter 1: Introduction to Ecosystem Science -- What Is an Ecosystem? -- What Are the Properties of Ecosystems? -- What Is in an Ecosystem? -- Ecosystems Have Structure -- Ecosystems Perform Functions -- Ecosystem Structure and Function Are Controlled by Many Factors -- Ecosystems Change Through Time -- How Do We Classify or Compare Ecosystems? -- Why Do Scientists Study Ecosystems? -- How Do Ecosystem Scientists Learn about Ecosystems? -- Approaches for Learning about Ecosystems -- Natural History -- Long-Term Studies -- Cross-Ecosystem Comparison -- Experiments -- Theory and Conceptual Models -- What Do Ecosystem Scientists Measure? -- Some Tools in the Ecosystem Scientists Toolbox -- Balances: Mass and Charge -- Tracers -- Spatial Data -- From There to Here: A Short History of the Ecosystem Concept in Theory and Practice -- References -- Further reading -- Section II : Ecological Energetics -- Introduction -- Units Used in Studies of Ecological Energetics -- References -- Chapter 2: Primary Production: The Foundation of Ecosystems -- Introduction -- Components of Primary Production -- Measuring Primary Production -- Aquatic Methods -- Terrestrial Methods -- Primary Production Methods: Advances -- Regulation of Primary Production -- Rates and Patterns of Primary Production -- Fates of Primary Production -- A Tale of Scale -- Summary -- References -- References for Table 2.1 -- Chapter 3: Secondary Production and Consumer Energetics -- Introduction -- Consumer Energetics -- The Energy Budget of Consumers -- Secondary Production -- Definition of Secondary Production -- Methods to Estimate Secondary Production -- Controls and Prediction of Secondary Production.

Objective: The objective of this work was to understand the relationship between eye movements and cognitive workload in maintaining lane position while driving. Background: Recent findings in driving research have found that, paradoxically, increases in cognitive workload decrease lateral position variability. If people drive where they look and drivers look more centrally with increased cognitive workload, then one could explain the decreases in lateral position variability as a result of changes in lateral eye movements. In contrast, it is also possible that cognitive workload brings about these patterns regardless of changes in eye movements. Method: We conducted three experiments involving a fixed-base driving simulator to independently manipulate eye movements and cognitive workload. Results: Results indicated that eye movements played a modest role in lateral position variability, whereas cognitive workload played a much more substantial role. Conclusions: Increases in cognitive workload decrease lane position variability independently from eye movements. These findings are discussed in terms of hierarchical control theory. Applications: These findings could potentially be used to identify periods of high cognitive workload during driving.

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 This on-road study employed behavioral and neurophysiological measurement techniques to assess the influence of six weeks of practice driving a Level 2 partially automated vehicle on driver workload and engagement. Background Level 2 partial automation requires a driver to maintain supervisory control of the vehicle to detect "edge cases" that the automation is not equipped to handle. There is mixed evidence regarding whether drivers can do so effectively. There is also an open question regarding how practice and familiarity with automation influence driver cognitive states over time. Method Behavioral and neurophysiological measures of driver workload and visual engagement were recorded from 30 participants at two testing sessions—with a six-week familiarization period in-between. At both testing sessions, participants drove a vehicle with partial automation engaged (Level 2) and not engaged (Level 0) on two interstate highways while reaction times to the detection response task (DRT) and neurophysiological (EEG) metrics of frontal theta and parietal alpha were recorded. Results DRT results demonstrated that partially automated driving placed more cognitive load on drivers than manual driving and six weeks of practice decreased driver workload—though only when the driving environment was relatively simple. EEG metrics of frontal theta and parietal alpha showed null effects of partial automation. Conclusion Driver workload was influenced by level of automation, specific highway characteristics, and by practice over time, but only on a behavioral level and not on a neural level. Application These findings expand our understanding of the influence of practice on driver cognitive states under Level 2 partial automation.

Objective: To conceptualize delivery of anesthesia as a control task, similar to control tasks in nonmedical domains, and to evaluate how presentation of new information and feedback affects task performance. Background: In anesthesia, integrated monitors that show intravenous drug and effect-site concentrations in a patient currently do not exist. However, using real-time displays of intravenous anesthetic concentrations and effects could significantly enhance intraoperative clinical performance. Pharmacological models are available to estimate past, present, and future drug concentrations in the brain and to predict the drug's physiological effects. A display that integrates pharmacological models and visualizes drug concentrations was developed and tested to see if this drug display significantly improved clinical performance. Method: Thirty three anesthesiologists with different levels of expertise administered anesthesia to simulated patients in a high-fidelity patient simulator. The experimental group used a drug display that visualized drug concentrations in real time, whereas the control group administered drugs without this information. Results: Anesthesiologists using the drug display achieved better hemodynamic control of the simulated patient than did the control group. Similarly, the drug display enabled anesthesiologists to wake up and reanimate the patient faster. Conclusion: Visual feedback of drug concentrations leads to superior performance in the delivery of anesthesia. Drug delivery can be conceptualized within a control theoretical framework. Finally, the drug display has significant clinical potential to increase patient safety. Application: Clinical performance in delivering anesthesia depends on feedback. By providing this feedback, the drug display supports clinicians' ability to more precisely and safely administer anesthesia.

Objective: This research aims to identify the impact of text messaging on simulated driving performance. Background: In the past decade, a number of on-road, epidemiological, and simulator-based studies reported the negative impact of talking on a cell phone on driving behavior. However, the impact of text messaging on simulated driving performance is still not fully understood. Method: Forty participants engaged in both a single task (driving) and a dual task (driving and text messaging) in a high-fidelity driving simulator. Results: Analysis of driving performance revealed that participants in the dual-task condition responded more slowly to the onset of braking lights and showed impairments in forward and lateral control compared with a driving-only condition. Moreover, text-messaging drivers were involved in more crashes than drivers not engaged in text messaging. Conclusion: Text messaging while driving has a negative impact on simulated driving performance. This negative impact appears to exceed the impact of conversing on a cell phone while driving. Application: The results increase our understanding of driver distraction and have potential implications for public safety and device development.

Objective: The purpose of this study was to explore the interrelationship between driver distraction and characteristics of driver behavior associated with reduced highway traffic efficiency. Background: Research on the three-phase traffic theory and on behavioral driving suggests that a number of characteristics associated with efficient traffic flow may be affected by driver distraction. Previous studies have been limited, however, by the fact that researchers typically do not allow participants to change lanes, nor do they account for the impact of varying traffic states on driving performance. Methods: Participants drove in three simulated environments with differing traffic congestion while both using and not using a cell phone. Instructed only to obey the speed limit, participants were allowed to vary driving behaviors, such as those involving forward following distance, speed, and lane-changing frequency. Results: Both driver distraction and traffic congestion were found to significantly affect lane change frequency, mean speed, and the likelihood of remaining behind a slower-moving lead vehicle. Conclusions: This research suggests that the behavioral profile of "cell phone drivers," which is often described as compensatory, may have far-reaching and unexpected consequences for traffic efficiency. Application: By considering the dynamic interplay between characteristics of traffic flow and driver behavior, this research may inform both public policy regarding in-vehicle cell phone use and future investigations of driving behavior.

Objective: To lay the foundation for a framework of just-in-time support (JITS) for novices dealing with urgent, unfamiliar tasks, and to evaluate a JITS system. Background: More than 350,000 people die annually of cardiac arrest in the United States. In response, automated defibrillators are advocated that, unfortunately, do not provide important respiratory support. This paper presents elements of a framework for a JITS system that instructs a lay responder to follow a treatment protocol for integrating respiratory support with the use of an automatic external defibrillator. Method: We simulated a medical emergency using a high-fidelity patient simulator and asked participants to care for the patient. Results: When using a paper-based NASA treatment protocol, participants made more errors and took longer to stabilize the injured person than when using the JITS system. Conclusion: These findings demonstrate the benefit of a JITS system to instruct novices in unfamiliar tasks. Application: The JITS system has the potential to improve the treatment outcome of victims of cardiac arrest. The JITS framework can be applied to many situations in which novices deal with urgent tasks without expertise available.