Inattentional blindness refers to that observers cannot detect some stimuli even if the stimuli stand exactly where their gaze falls. This phenomenon is common among our daily life and contributes to many traffic and medical accidents. We reviewed the papers and found that “limited resource” and “attentional set” take accounts to this phenomenon. In general, the two causes contribute to this phenomenon simultaneously. However, “attentional set” will lead to this phenomenon independent of “limited resource”. More in depth, from the aspect of neuro-mechanism, “limited resource” and “attentional set” acted on the middle stage of brain processing. The unexpected stimuli have ever received some conscious processing in the traditional conscious processing region even when they are not been aware of. The conscious inputs in occipital-parietal areas in the middle stage, the activation level of temporo-parietal junction and intraparietal sulcus determine whether the unexpected stimuli can arrive to conscious level.

BACKGROUND: The goal of the current work was to create a publicly available visualization tool of distracted driving research, the purpose of which is to allow the public and other stakeholders to empirically inform questions of their choice that may bear on policy discussions. METHODS: Fifty years of distracted driving research was used to design a comprehensive database of studies that evaluated the effects of distraction on driving performance. Distraction sources (e.g., texting, talking, visual distraction) and performance measures were defined, and the sample of studies were evaluated and categorized by their measures. RESULTS: The final product yielded 342 studies using various methodologies. Across all measures, 1297 found distractions degraded driving performance, 54 found distraction improved driving performance, and 257 found distraction had no effect on driving performance. An analysis of the most common phone distractions (texting and talking) showed that texting almost always results in degraded performance. Aggregate data reveal no difference in performance decrements for hand-held or hands-free phones even though single studies of those variables vary in their outcomes. CONCLUSIONS: This project illustrates how scientific research can be made publically available for use by a diverse audience of stakeholders. An important result of this project is that data aggregated along a simple set of characteristics such as whether or not performance is decreased, improved or not affected, can reveal trends in the data that are less clear from any individual study.Copyright 2016 Elsevier Ltd. All rights reserved.

The ability to detect changes is crucial for safe driving. Previous research has demonstrated that drivers often experience change blindness, which refers to failed or delayed change detection. The current study explored how susceptibility to change blindness varies as a function of the driving environment, type of object changed, and safety relevance of the change. Twenty-six fully-licenced drivers completed a driving-related change detection task. Changes occurred to seven target objects (road signs, cars, motorcycles, traffic lights, pedestrians, animals, or roadside trees) across two environments (urban or rural). The contextual safety relevance of the change was systematically manipulated within each object category, ranging from high safety relevance (i.e., requiring a response by the driver) to low safety relevance (i.e., requiring no response). When viewing rural scenes, compared with urban scenes, participants were significantly faster and more accurate at detecting changes, and were less susceptible to ooked-but-failed-to-see errors. Interestingly, safety relevance of the change differentially affected performance in urban and rural environments. In urban scenes, participants were more efficient at detecting changes with higher safety relevance, whereas in rural scenes the effect of safety relevance has marginal to no effect on change detection. Finally, even after accounting for safety relevance, change blindness varied significantly between target types. Overall the results suggest that drivers are less susceptible to change blindness for objects that are likely to change or move (e.g., traffic lights vs. road signs), and for moving objects that pose greater danger (e.g., wild animals vs. pedestrians).

Performing two cognitive tasks at the same time can degrade performance for either domain-general reasons (e.g., both tasks require attention) or domain-specific reasons (e.g., both tasks require visual working memory). We tested predictions of these two accounts of interference on the task of driving while using language, a naturally occurring dual task. Using language and driving a vehicle use different perceptual and motor skills. As a consequence, a domain-general explanation for interference in this dual task appears most plausible. However, recent evidence from the language processing literature suggests that when people use language with motor content (e.g., language about actions) or visual content (e.g., language about visible objects and events), they engage their motor and perceptual systems in ways specifically reflecting the actions and percepts that the language is about. This raises the possibility that language might interfere with driving for domain-specific reasons when the language has visual or motor content. To test this, we had participants drive a simulated vehicle while simultaneously answering true false statements that had motor, visual, or abstract content. A domain-general explanation for interference would predict greater distraction in each of these three conditions compared with control, while a domain-specific explanation would predict greater interference in the motor and visual conditions. Both of these predictions were borne out but on different measures of distraction, suggesting that language-driven distraction during driving and dual tasks involving language in general may be the result not only of domain-general causes but also specific interference caused by linguistic content.

Objectives: Examine how driving experience and expectations affect the ability of experienced drivers to identify traffic signs - specifically, no right turn (NRT) and no left turn (NLT) at intersections. Background: Failure to heed signs is a frequent cause of accidents, and the authors focused on the contributions of experience and expectancy to sign identification. Method: Inexperienced and experienced drivers were connected to an eye tracker system and briefly exposed to various traffic scenes. Some of the pictures included an NRT sign at the expected location (on the right), and some included the same sign at an unexpected location (on the left). The same procedure was used with an NLT traffic sign. Results: Experienced drivers identified traffic signs better than inexperienced drivers did when the signs were posted at the expected location but identified them worse than did inexperienced drivers when they were at unexpected locations. Conclusions: With experience, drivers' expectations regarding the expected location of traffic signs become so strong that violating these expectancies results in more identification errors among experienced drivers than among inexperienced drivers. To optimize experienced drivers' traffic sign identification, signs must be located in accordance with drivers' expectations - specifically, on the right side of the road. Applications: When signs are misplaced, crashes can be caused by inappropriate placement rather than inappropriate driving. Highway designers should ensure that their design conforms to standards that shape experienced drivers' expectations.

The effects of imagery-induced distraction on hazard perception and eye movements were investigated in 2 simulated driving experiments. Experiment 1: sixty participants viewed and responded to 2 driving films containing hazards. Group 1 completed the task without distraction; group 2 completed a concurrent imagery inducing telephone task; group 3 completed a non imagery inducing telephone task. Experiment 2: eye-tracking data were collected from forty-six participants while they reacted to hazards presented in 16 films of driving scenes. 8 films contained hazards presented in either central or peripheral vision and 8 contained no hazards. Half of the participants performed a concurrent imagery-inducing task. Compared to undistracted participants, dual-taskers were slower to respond to hazards; detected fewer hazards; committed more “looked but failed to see” errors; and demonstrated “visual tunnelling”. Telephone conversations may interfere with driving performance because the two tasks compete for similar processing resources, due to the imagery-evoking aspects of phone use.

Perceptual load theory offers a resolution to the long-standing early vs. late selection debate over whether task-irrelevant stimuli are perceived, suggesting that irrelevant perception depends upon the perceptual load of task-relevant processing. However, previous evidence for this theory has relied on RTs and neuroimaging. Here we tested the effects of load on conscious perception using the “inattentional blindness” paradigm. As predicted by load theory, awareness of a task-irrelevant stimulus was significantly reduced by higher perceptual load (with increased numbers of search items, or a harder discrimination vs. detection task). These results demonstrate that conscious perception of task-irrelevant stimuli critically depends upon the level of task-relevant perceptual load rather than intentions or expectations, thus enhancing the resolution to the early vs. late selection debate offered by the perceptual load theory.

The lived environment is the arena where our cognitive skills, preferences, and attitudes come together to determine our ability to interact with the world. The mechanisms through which lived environments can benefit cognitive health in older age are yet to be fully understood. The existing literature suggests that environments which are perceived as stimulating, usable and aesthetically appealing can improve or facilitate cognitive performance both in young and older age. Importantly, optimal stimulation for cognition seems to depend on experiencing sufficiently stimulating environments while not too challenging. Environmental complexity is an important contributor to determining whether an environment provides such an optimal stimulation. The present paper reviews a selection of studies which have explored complexity in relation to perceptual load, environmental preference and perceived usability to propose a framework which explores direct and indirect environmental influences on cognition, and to understand these influences in relation to aging processes. We identify ways to define complexity at different environmental scales, going from micro low-level perceptual features of scenes, to design qualities of proximal environments (e.g., streets, neighborhoods), to broad geographical areas (i.e., natural vs. urban environments). We propose that studying complexity at these different scales will provide new insight into the design of cognitive-friendly environments.

The most frequent cause of motorcycle accidents occurs when another vehicle violates the motorcycle’s right-of-way at an intersection. In addition to detection errors, misperception of the approaching motorcycle’s speed and time-to-arrival is another driver error that accounts for these accidents, although this error has been studied less often. Such misperceptions have been shown to be related to the small size of motorcycles and to their small angular velocity when approaching. In two experiments we tested the impact of different motorcycle headlight configurations in various ambient lighting conditions (daytime, dusk, and nighttime). The participants drove on a driving simulator and had to turn left across a line of vehicles composed of motorcycles and cars. The motorcycles were approaching at different speeds and were equipped with either a “standard” headlight, a “horizontal” configuration (added to the standard headlight were two lights on the rearview mirrors so as to visually increase the horizontal dimension of the motorcycle), a “vertical” configuration (one light on the rider’s helmet and two lights on the fork were added to the standard headlight so as to increase the vertical dimension of the motorcycle), or a “combined” configuration (combining the horizontal and vertical configurations). The findings of the first experiment in nighttime conditions indicated that both the vertical and combined configurations significantly increased the gap car drivers accepted with respect to the motorcycle as compared to the standard configuration, and that the accepted gaps did not differ significantly from those accepted for cars. The advantage of the vertical and combined configurations showed up especially when the motorcycle’s approach speed was high. The findings of the second experiment in dusk and daytime conditions indicated similar patterns, but the headlight-configuration effect was less pronounced at dusk, and nonsignificant during the day. The results are discussed with regards to possible applications for motorcycles.

Novice drivers (teen drivers with their solo license for 6 months or less) are at a greatly inflated risk of crashing. Post hoc analyses of police accident reports indicate that novice drivers fail to anticipate hazards, manage their speed, and maintain attention. These skills are much too broadly defined to be of much help in training. Recently, however, driving simulators have been used to identify those skills which differentiate the novice drivers from older, more experienced drivers in the areas of hazard anticipation and speed management. Below, we report an experiment on a driving simulator which compares novice and experienced drivers performance in the third area believed to contribute especially heavily to crashes among novice drivers: attention to the forward roadway. The results indicate that novice drivers are much more willing to glance for long periods of time inside the vehicle than are experienced drivers. Interestingly, the results also indicate that both novice and experienced drivers spend equal amounts of time glancing at tasks external to the vehicle and in the periphery. Moreover, just as a program has been designed to train the scanning skills that clearly differentiate novice from experienced drivers, one might hope that a training program could be designed to improve the attention maintenance skills of novice drivers. We report on the initial piloting of just such a training program. Finally, we address a question that has long been debated in the literature: Do the results from driving simulators generalize to the real world? We argue that in the case of hazard anticipation, speed management, and attention maintenance the answer is yes.

This paper describes our research into the processes that govern driver attention and behavior in familiar, well-practiced situations. The experiment examined the effects of extended practice on inattention blindness and detection of changes to the driving environment in a high-fidelity driving simulator. Participants were paid to drive a simulated road regularly over 3 months of testing. A range of measures, including detection task performance and driving performance, were collected over the course of 20 sessions. Performance from a yoked Control Group who experienced the same road scenarios in a single session was also measured. The data showed changes in what drivers reported noticing indicative of inattention blindness, and declining ratings of mental demand suggesting that many participants were "driving without awareness". Extended practice also resulted in increased sensitivity for detecting changes to road features associated with vehicle guidance and improved performance on an embedded vehicle detection task (detection of a specific vehicle type). The data provide new light on a "tandem model" of driver behavior that includes both explicit and implicit processes involved in driving performance. The findings also suggest reasons drivers are most likely to crash at locations very near their homes. (C) 2013 Elsevier Ltd. All rights reserved.

Risk perception and distribution of visual attention while driving are crucial elements for accident prevention and new-driver improvement. This study investigates how racing videogames could shape the visual exploration of virtual and real road in male pre-drivers. The visual performance of players of racing video games with and without driver’s license was tested in virtual vs. real scenarios. Attention to specific elements of different types of road interactions was monitored using an eye-tracking system. Results showed that habitual use of racing video games was not found to foster a positive effect on users’ distribution of visual attention, supporting visual patterns typical of novice drivers. Gamers without driving experience replicated the same patterns in a real road scenario, ignoring road signs and potential areas of interactions with other drivers, while experienced drivers gamers explored video games roads like real roads. The fact that the gamers’ driving performance was not comparable to drivers in the virtual scenario suggests that there are other variables in the gameplay that create a less complex traffic scene, still the visual complexity of different real road interactions is kept in video game interactions, opening new perspectives towards gamers’ visual exploration of the road.

Previous research on motorcycle crashes has shown the frequency and severity of accidents in which a non-priority road user failed to give way to an approaching motorcyclist without seeing him/her, even though the road user had looked in the approaching motorcycle's direction and the motorcycle was visible. These accidents are usually called “looked-but-failed-to-see” (LBFS) accidents. This article deals with the effects that the motorcyclist's speed has in these accidents. It is based on the in-depth study and precise kinematic reconstruction of 44 accident cases involving a motorcyclist and another road user, all occurring in intersections. The results show that, in urban environments, the initial speeds of motorcyclists involved in “looked-but-failed-to-see” accidents are significantly higher than in other accidents at intersections. In rural environments, the difference in speed between LBFS accidents and other accidents is not significant, but further investigations would be necessary to draw any conclusions. These results suggest that speed management, through road design or by other means, could contribute to preventing “looked-but-failed-to-see” motorcycle accidents, at least in urban environments.

Motorcycle accidents have somewhat different characteristics from accidents involving other classes of road user. They include in particular ‘right of way’ accidents, and accidents involving loss of control on curves or bends.A sample of 1790 accident cases was considered, including 1003 in detail, from UK midland police forces, involving motorcyclists of all ages, and covering the years 1997–2002 inclusive.Significant differences were discovered in the sample with respect to types of accidents involving motorcyclists (and their blameworthiness). There seems to be a particular problem surrounding other road users’ perception of motorcycles, particularly at junctions. Such accidents often seem to involve older drivers with relatively high levels of driving experience who nonetheless seem to have problems detecting approaching motorcycles. Motorcyclists themselves seem to have far more problems with other types of accident, such as those on bends or curves. The implications of these findings are discussed.

Visual fixations at vertical road signs and their recall was tested in 22 participants who drove a route of 8.34km. Gaze was assessed by mobile eye tracking glasses. Recall was assessed at the end of the route by asking each participant to write in a route map all vertical sign that were remembered. The route was the same for all participants and included a total of 75 road signs. The results shown that only 25.06% of vertical signs were looked, and only 6.66% were recalled by the driver at the end of the route. The results are explained in terms of inattentional blindness, automaticity in driving behavior, and the angular offset of the vertical signs to the driver sight line.

Motorcyclists are grossly over-represented in the crash statistics. They represent 1 per cent of traffic in the United Kingdom but 21 per cent of all fatalities. The analysis of collision data suggests that some of the most common motorcyclist collisions involve errors on behalf of other road users, for example car drivers who fail to give way to an approaching motorcycle at a T-junction. Following such accidents, car drivers often claim that they looked, but did not see the approaching motorcycle. Research needs to assess whether such 'Look But Fail To See' accidents occur and what factors might contribute to their prevalence. This project involved three studies to explore these issues further. These were: 1. a study to increase car drivers' empathy for motorcyclists; 2. a study to investigate how drivers search for motorcycles at T-junctions and when changing lanes; and 3. a study to assess whether training interventions can address poor visual skills at T-junctions and when changing lanes.

Studies of accident statistics suggest that motorcyclists are particularly vulnerable to collisions with other vehicles which pull out of side roads onto a main carriageway, failing to give way to the approaching motorcycle. Why might this happen? The typical response of the car driver is that they looked in the appropriate direction but simply failed to see the motorcycle. To assess the visual skills of drivers in such scenarios we compared the behaviour of novice and experienced drivers to a group of dual drivers (with both car and motorcycle experience). Participants watched a series of video clips, displayed across three screens, depicting the approach to various t-junctions. On reaching the junction, participants had to decide when it was safe to pull out. Responses and eye movements were measured. The results confirmed that dual drivers had the safest responses at junctions, especially in the presence of conflicting motorcycles. On a range of visual measures both novice and experienced drivers appeared inferior to dual drivers, though for potentially different reasons. There were however no differences in the time it took all drivers to first fixate approaching motorcycles. Instead the differences appeared to be due to the amount of time spent looking at the approaching motorcycle. The experienced drivers had shorter gazes on motorcycles than cars, suggesting that they either process less salient motorcycles faster than cars, or that they terminated the gaze prematurely perhaps because they did not realise they were fixating a motorcycle. We argue that this is potential evidence for an oculomotor basis for Look But Fail To See errors.

The most common type of conflict in which a motorcyclist is injured or killed is a collision between a motorcycle and a car, often in priority situations. Many studies on motorcycle safety focus on the question why car drivers fail to give priority and on the poor conspicuity of motorcycles. The concept of ‘looked-but-failed-to-see’ crashes is a recurring item. On the other hand, it is not entirely unexpected that motorcycles have many conflicts with cars; there simply are so many cars on the road. This paper tries to unravel whether – acknowledging the differences in exposure – car drivers indeed fail to yield for motorcycles more often than for other cars. For this purpose we compared the causes of crashes on intersections (e.g. failing to give priority, speeding, etc.) between different crash types (car–motorcycle or car–car). In addition, we compared the crash causes of dual drivers (i.e. car drivers who also have their motorcycle licence) with regular car drivers. Our crash analysis suggests that car drivers do not fail to give priority to motorcycles relatively more often than to another car when this car/motorcycle approaches from a perpendicular angle. There is only one priority situation where motorcycles seem to be at a disadvantage compared to cars. This is when a car makes a left turn, and fails to give priority to an oncoming motorcycle. This specific crash scenario occurs more often when the oncoming vehicle is a motorcycle than when it is a car. We did not find a significant difference between dual drivers and regular car drivers in how often they give priority to motorcycles compared to cars.

Background The purpose of this study was to examine the association between secondary task involvement and risk of crash and near-crash involvement among older drivers using naturalistic driving data. Methods Data from drivers aged ≥70 years in the Strategic Highway Research Program (SHRP2) Naturalistic Driving Study database was utilized. The personal vehicle of study participants was... [Show full abstract]

Objective: The main objective of this paper was to outline an explanatory framework for understanding effects of cognitive load on driving performance and to review the existing experimental literature in the light of this framework. Background: While there is general consensus that taking the eyes off the forward roadway significantly impairs most aspects of driving, the effects of primarily cognitively loading tasks on driving performance are not well understood. Method: Based on existing models of driver attention, an explanatory framework was outlined. This can be summarized in terms of the cognitive control hypothesis: Cognitive load selectively impairs driving sub-tasks that rely on cognitive control but leaves automatic performance unaffected. An extensive literature review was conducted where existing results were re-interpreted based on the proposed framework. Results: It was demonstrated that the general pattern of experimental results reported in the literature aligns well with the cognitive control hypothesis and that several apparent discrepancies between studies can be reconciled based on the proposed framework. More specifically, performance on non-practiced or inherently variable tasks, relying on cognitive control, is consistently impaired by cognitive load while the performance on automatized (well-practiced and consistently mapped) tasks is unaffected and sometimes even improved. Conclusion: Effects of cognitive load on driving are strongly selective and task-dependent. Application: The present results have important implications for the generalization of results obtained from experimental studies to real world driving. The proposed framework can also serve to guide future research on the potential causal role of cognitive load in real-world crashes.

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 likelihood of any particular SPIDER activity being completed successfully (because of a concurrent secondary task performance) would lead to a large increase in the relative risk of a crash.

Over the years, PTWs number of accidents have increased dramatically and have accounted for a high percentage of the total traffic fatalities. The majority of those accidents occur in daylight, clear weather, and at light to moderate traffic conditions. The current study included two experiments. The first experiment evaluated the influence of PTW attention conspicuity on the ability of un-alerted viewers to detect it, whereas the second experiment evaluated the PTWs search conspicuity to alerted viewers. The independent variables in both experiments included driving scenarios (urban and inter-urban), PTW rider's outfit (black, white, and reflective) and PTW distance from the viewer. 66 students participated in experiment 1. Every participant was presented with a series of pictures and was asked to report all the vehicle types present in each picture. Experiment 2 included 64 participants and incorporated the same pictures as experiment 1. However, in this experiment the participants were instructed to search the pictures for a PTW and to report its presence or absence as soon as they reach a decision. In experiment 1 the detection of a PTW depended on the interaction between its distance from the viewer, the driving scenario and PTW rider's outfit. For an un-alerted viewer when the PTW was distant the different outfit conditions affected its attention conspicuity. In urban roads, where the background surrounding the PTW was more complex and multi-colored, the reflective and white outfits increased its attention conspicuity compared to the black outfit condition. In contrast, in inter-urban roads, where the background was solely a bright sky, the black outfit provided an advantage for the PTW detectability. In experiment 2, the average PTW detection rate of the alerted viewers was very high and the average reaction time to identify the presence of a PTW was the shortest in the inter-urban environment. Similar to the results of experiment 1, in urban environments the reflective and white clothing provided an advantage to the detection of the PTW, while in the inter-urban environment the black outfit presented an advantage. Comparing the results of the two experiments revealed that at the farthest distance, the increased awareness in the search conspicuity detection rates were three times higher than in the attention conspicuity. The conspicuity of a PTW can be increased by using an appropriate rider's outfit that distinguishes him/her from the background scenery. Thus, PTW riders can actively increase their conspicuity by taking into account the driving route (crowded urban/inter urban), eventually increasing the probability of being detected by the other road users. In addition, increasing the alertness and expectancy of drivers to the presence of PTWs can increase their search conspicuity.

Background: The phenomenon of Change Blindness (CB) has been invoked in a number of fields of psychology, particularly eyewitness misidentification, but also hazard perception in driving behaviour. An extensive review of the existing literature suggested that there has been no systematic review to date that has investigated what factors affect CB in real-world contexts.Purpose: This article aims to systematically review factors affecting CB when measured using film or real-world paradigms.Method: Six electronic databases were searched for relevant references, alongside four E-theses. Seven experts were contacted for current and unpublished studies. Each study was compared against inclusion criteria, prior to selection and data synthesis.Results: The full search yielded 12,656 publications; 3,654 duplicates were removed and an additional 8,693 irrelevant publications were excluded. A further 295 publications were removed for not meeting the inclusion criteria. One conference abstract was excluded as contact with the authors produced no response. A total of 13 articles that met the criteria were reviewed.Conclusion: Increasing attention, the saliency of the changed object and spatial violations significantly reduce CB, specifically when measured using the real-world and film paradigms; these have implications for forensic psychology practice relevant to innocent bystanders and eyewitness misidentifications, and witnesses making positive identifications. However, a number of methodological limitations were identified which should be taken into account in designing future research.

react-text: 176 Load Theory (Lavie, 1995, 2005) states that the level of perceptual load in a task (i.e., the amount of information involved in processing task-relevant stimuli) determines the efficiency of selective attention. There is evidence that perceptual load affects distractor processing, with increased inattentional blindness under high load. Given that high load can result in individuals failing to... /react-text react-text: 177 /react-text [Show full abstract]

This paper presents a computational model of visual attention incorporating a cognitive imperfection known as inattentional blindness. We begin by presenting four factors that determine successful attention allocation: conspicuity, mental workload, expectation and capacity. We then propose a framework to study the effects of those factors on an unexpected object and conduct an experiment to measure the corresponding subjective awareness level. Finally, we discuss the application of a visual attention model for conversational agents.

Motorcycle-automobile accidents occur predominantly when the car driver turns left across the motorcyclist's right-of-way. Efforts to decrease this specific collision configuration, through an increase in motorcycle conspicuity, have concentrated on the physical characteristics of the motorcycle and its rider. The work reported here examines the behavior of car drivers during different driving sequences, in particular during left-turn maneuvers. An experiment is reported that used simultaneous video-taping of the driver and the forward-looking scene. Subjects followed a preset on-road course and were observed for head movements to determine the possibility of structural interference eye-blink frequency, probe-response time, and probe response error, as measures of cognitive or mental workload. In addition, the subjects completed two major subjective workload evaluations as reflections of effort directed to different components of the driving task. Results indicated that there were significant increases in head movements and mental workload during turn sequences compared to straight driving. This result of higher driver workload may be responsible for increasing the potential for detection failure. Such a propensity is also fostered by the higher structural interference that may be expected during turns. Failures to observe during turning sequences have differing outcomes depending on the presence of opposing traffic, as during the left turn, compared with the absence of such opposition, as occurs in the right turn. Also, the less conspicuous the oncoming vehicle in the left turn scenario, the higher the probability of detection failure. At the present time the least conspicuous powered vehicle is the motorcycle.

Inattentional blindness (IB) is the inability to detect a salient yet unexpected task irrelevant stimulus in one’s visual field when attention is engaged in an ongoing primary task. The present study is the first to examine the impact of both task difficulty and alcohol consumption on IB and primary task performance. On the basis of alcohol myopia theory, the combined effects of increased task difficulty and alcohol intoxication were predicted to impair task performance and restrict the focus of attention on to task-relevant stimuli. We therefore expected increases in breath alcohol concentration to be associated with poorer primary task performance and higher rates of IB, with these relationships being stronger under hard than easy task conditions. This hypothesis was tested in a field study where alcohol drinkers in a local bar were randomly assigned to perform a dynamic IB task with an easy or hard visual tracking and counting task at its core (Simons and Chabris in Perception 28:1059–1074,1999). Increasing the difficulty of the primary task reduced task accuracy but, surprisingly, had no impact on the rate of IB. Higher levels of alcohol intoxication were, however, associated with poorer task performance and an increased rate of IB, but only under easy primary task conditions. Results are consistent with alcohol myopia theory. Alcohol intoxication depletes attentional resources, thus reducing the drinker’s awareness of salient stimuli that are irrelevant to some ongoing primary task. We conclude that this effect was not observed for our hard task because it is more resource intensive, so leaves no spare attentional capacity for alcohol to deplete.

In the present research, we investigated the hypothesis that working memory mediates conversation-induced impairment of situation awareness (SA) while driving. Although there is empirical evidence that conversation impairs driving performance, the cognitive mechanisms that mediate this relationship remain underspecified. Researchers have reported that a phonological working memory task decreased drivers' SA for vehicles located behind them whereas a visuospatial working memory task impaired SA for vehicles ahead. Conversation, therefore, might impair SA for vehicles behind the driver by preferentially taxing the phonological loop. A 20-questions task was used as a proxy for natural conversation. In Experiment I, driving performance was measured across three within-subjects conversation conditions (i.e., no conversation, driver asks questions, driver answers questions) with the use of a driving simulator. In Experiment 2, participants drove in the same simulator while either conversing (20-questions task) or not Participants estimated the positions of other vehicles after the screens were blanked at the end of each trial. Speed monitoring and responses to visual probes were impaired by the 20-questions conversation task (Experiment 1). As predicted, conversation impaired SA for the location of other vehicles more for vehicles located behind the driver than for those in front (Experiment 2). Conversation impairs drivers' SA of vehicles behind them by taxing working memory's phonological loop and impairs SA generally by taxing working memory's central executive. Provides a theoretical framework that links driver SA to working memory and a mechanism for understanding why conversation impairs driving performance.

Three experiments examined some of the factors that might affect motorcyclists'' conspicuity to other road users. In each case, subjects saw a sequence of slides showing traffic, some of which contained a motorcyclist. A record was taken of their reaction times to decide whether or not a motorcyclist was present in each slide. Experiments 1 and 2 examined the effects on conspicuity of headlight use, type of clothing, distance of motorcyclist from viewer, and driving situation (urban or semi-rural). Experiment 3 looked more closely at environmental influences on motorcyclist conspicuity, systematically varying the level of background 090004clutter090005 behind the motorcyclist. All three experiments indicate that the effectiveness of the conspicuity aids used, especially clothing, may depend on the situation in which the motorcyclist was located: bright clothing and headlight use may not be infallible aids to conspicuity. Brightness contrast between the motorcyclist and the surroundings may be more important as a determinant of conspicuity than the motorcyclist''s brightness per se. Motorcyclists'' conspicuity is a more complex issue than has hitherto been acknowledged.

[Abstract unavailable]

Observers often fail to detect the appearance of an unexpected visual object (“inattentional blindness”). Experiment 1 studied the effects of fixation position and spatial attention on inattentional blindness. Eye movements were measured. We found strong inattentional blindness to the unexpected stimulus even when it was fixated and appeared in one of the expected positions. The results suggest that spatial attention is not sufficient for attentional capture and awareness. Experiment 2 showed that the stimulus was easier to consciously detect when it was colored but the relation of the color to the color of the attended objects had no effect on detection. The unexpected stimulus was easiest to detect, when it represented the same category as the attended objects.

Inattentional blindness—the phenomenon that clearly visible, yet currently unexpected objects go unnoticed when our attention is focused elsewhere—is an ecologically valid failure of awareness. It is currently subject to debate whether previous events and experiences determine whether or not inattentional blindness occurs. Using a simple two-phase paradigm in the present study, we found that the likelihood of missing an unexpected object due to inattention did not change when its defining characteristic (its color) was perceptually preactivated (Experiment 1; N 62=62188). Likewise, noticing rates were not significantly reduced if the object’s color was previously motivationally relevant during an unrelated detection task (Experiment 2; N 62=62184). These results corroborate and extend recent findings questioning the influence of previous experience on subsequent inattentional blindness. This has implications for possible countermeasures intended to thwart the potentially harmful effects of inattention.

In everyday life, eye movements enable the eyes to gather the information required for motor actions. They are thus proactive, anticipating actions rather than just responding to stimuli. This means that the oculomotor system needs to know where to look and what to look for. Using examples from table tennis, driving and music reading we show that the information the eye movement system requires is very varied in origin and highly task specific, and it is suggested that the control program or schema for a particular action must include directions for the oculomotor and visual processing systems. In many activities (reading text and music, typing, steering) processed information is held in a memory buffer for a period of about a second. This permits a match between the discontinuous input from the eyes and continuous motor output, and in particular allows the eyes to be involved in more than one task.

No abstract available

Drivers who collide with a vehicle that is parked on the hard shoulder of a motorway or dual-carriageway sometimes claim not to have seen it before the collision. Previous research into vehicle conspicuity has taken such 090004looked but failed to see090005 claims at face value, and concentrated on attempting to remedy the problem by making vehicles more conspicuous in sensory terms. However, the present study describes investigations into accidents of this kind which have involved stationary police cars, vehicles which are objectively highly conspicuous. Two laboratory studies showed that experienced drivers viewing a film of dual-carriageway driving were slower to respond to a parked police car as a 090004hazard090005 if it was parked directly in the direction of travel than if it was parked at an angle; this effect was more pronounced when the driver''s attention was distracted with a secondary reasoning task. Taken together with the accident reports, these results suggest that 090004looked but failed to see090005 accidents may arise not because the parked vehicle is difficult to see, but for more cognitive reasons, such as vigilance failure, or possession by the driver of a 090004false hypothesis090005 about the road conditions ahead. An emergency vehicle parked in the direction of travel, with only its blue lights flashing, may encourage drivers to believe that the vehicle is moving rather than stationary. Parking at an angle in the road, and avoiding the use of blue lights alone while parked, are two steps that drivers of parked emergency vehicles should consider taking in order to alert approaching drivers to the fact that a stationary vehicle is ahead.

The ability to remain focused on goal-relevant stimuli in the presence of potentially interfering distractors is crucial for any coherent cognitive function. However, simply instructing people to ignore goal-irrelevant stimuli is not sufficient for preventing their processing. Recent research reveals that distractor processing depends critically on the level and type of load involved in the processing of goal-relevant information. Whereas high perceptual load can eliminate distractor processing, high load on ‘frontal’ cognitive control processes increases distractor processing. These findings provide a resolution to the long-standing early and late selection debate within a load theory of attention that accommodates behavioural and neuroimaging data within a framework that integrates attention research with executive function.

Motorcyclists are particularly vulnerable to injury in crashes with heavy vehicles due to substantial differences in vehicle mass, the degree of protection and speed. There is a considerable difference in height between motorcycles and trucks; motorcycles are viewed by truck drivers from downward angles, and shorter distances between them mean steeper downward angles. Hence, we anticipated that the effects of motorcycle conspicuity treatments would be different for truck drivers. Therefore, this study aims to evaluate the effects of motorcycle conspicuity treatments on the identification and detection of motorcycles by truck drivers. Two complementary experiments were performed; the first experiment assessed the impact of motorcycle sensory conspicuity on the ability of un-alerted truck drivers to detect motorcycles, and the second experiment assessed the motorcycle cognitive conspicuity to alerted truck drivers. The sensory conspicuity was measured in terms of motorcycle detection rates by un-alerted truck drivers when they were not anticipating a motorcycle within a realistic driving scene, while the cognitive conspicuity was determined by the time taken by alerted truck drivers to actively search for a motorcycle. In the first experiment, the participants were presented with 10 pictures and were instructed to report the kinds of vehicles that were presented in the pictures. Each picture was shown to the participants for 600ms. In the second experiment, the participants were presented with the same set of pictures and were instructed to respond by clicking the right button on a mouse as soon as they detected a motorcycle in the picture. The results indicate that the motorcycle detection rate increases, and the response time to search for a motorcycle decreases, as the distance between the targeted motorcycle and the viewer decreases. This is true regardless of the type of conspicuity treatment used. The use of daytime running headlights (DRH) was found to increase the detection rate and the identification of a motorcycle by a truck driver at a farther distance, but effect deteriorates as the distance decreases. The results show that the detection rate and the identification of a motorcyclist wearing a black helmet with a reflective sticker increases as the distance between the motorcycle and the truck decreases. We also found that a motorcyclist wearing a white helmet and a white outfit is more identifiable and detectable at both shorter and longer distances. In conclusion, although this study provides evidence that the use of appropriate conspicuity treatments enhances motorcycle conspicuity to truck drivers, we suggest that more attention should be paid to the effect of background environment on motorcycle conspicuity.

Both perceptual errors (failing to perceive) and appraisal errors (failing to make a correct judgment about safety) could explain the relatively high number of pulling out at the junctions involving approaching motorcycles in relation to cars. Two experiments were conducted to investigate the effect of exposure to motorcycles on these types of errors by comparing drivers from Malaysia where motorcycles are very common with drivers from the UK where motorcycles are rare. Experiment 1 investigated drivers ability to perceive approaching vehicles (car or motorcycle) located at different distances (near, intermediate and far) on UK and Malaysian roads. There was no difference between Malaysian and UK drivers in overall ability to perceive the approaching vehicles but Malaysian drivers were relatively good at perceiving motorcycles at further distances. Experiment 2 investigated drivers judgments about whether or not it was safe to pull out on the same roads and found that Malaysian drivers were more likely to judge it was safe to pull out as compared to UK drivers. Findings suggest that high exposure to motorcycles may reduce vehicle effects on perception for Malaysian drivers. However they may make more risky appraisals about safety of pulling out, which might contribute to the high accident and fatality rates in Malaysia.

The current study focuses on Change Blindness in a road environment. The purpose of the experiment is to study how the type of change induced affects the strength of Change Blindness and the role of glance duration and attention. Hundred-thirty-one participants watched video films showing six drives around a block filmed from the drivers viewpoint. They were instructed to look for a traffic related change from one drive to the next. Eye glance duration to traffic signs was measured, as well as Change Blindness. In drive 6, one of the traffic signs was changed into another traffic sign, with four different types of changes. The experiment showed that longer glances to the traffic signs in general predict Change Awareness in case of a change, whereas shorter glances predict Change Blindness. If the change is explicitly perceived, this resulted in even longer glances to the changed sign. Change detection improved with a larger difference between the original and the changed sign, with the traffic sign not fitting the scene and when attention was raised by means of an auditory message.Research highlights? Glance duration to stimuli in general predicts change detection. ? No indications of longer glances in condition that lead to better Change Detection. ? Large effect of type of change and fitting within the scene on change detection. ? No indications for implicit information processing for the Change Blind.

SummaryA set of experiments gauged the value of salient and non-salient visual information to drivers' decision making. Stimuli were images of traffic scenes viewed from a drivers' approximate perspective, and the subjects' task was to make stop-or-go driving judgments. Under some experimental conditions (Experiment 1), subjects viewed only the salient information from within each scene. Under other conditions (Experiments 2 3), they viewed only the non-salient information. A signal detection measure of sensitivity served as the primary dependent measure. Data indicated that an above-chance amount of the information needed for accurate judgments was contained within salient image regions and that some information was available only from the salient regions. Other critical information, however, was contained exclusively within non-salient regions. Results suggest that an attentional bias toward visual salience would serve as an economical information-seeking strategy for drivers but by itself would overlook many task-critical cues. Copyright 2013 John Wiley & Sons, Ltd.

Voluntary and relatively involuntary subsystems of attention often compete. On one hand, people can intentionally “tune” attention for features that then receive visual priority; on the other hand, more reflexive attentional shifts can “short-circuit” top-down control in the face of urgent, behaviourally relevant stimuli. Thus, it is questionable whether voluntary attentional tuning (i.e., attentional set) can affect one's ability to respond to unexpected, urgent information in the real world. We show that the consequences of such tuning extend to a realistic, safety-relevant scenario. Participants drove in a first-person driving simulation where they searched at every intersection for either a yellow or blue arrow indicating which way to turn. At a critical intersection, a yellow or blue motorcycle—either matching or not matching drivers’ attentional set—suddenly veered into drivers’ paths and stopped in their way. Collision rates with the motorcycle were substantially greater when the motorcycle did not match drivers’ attentional sets.

Perceptual load theory of attention predicts that the level of perceptual load in a primary task affects the processing of additional stimuli. Given the lack of ecologically valid evidence for the model, the current study assessed the effect of perceptual load on driver awareness during simulated driving tasks. The results showed that perceptual load dramatically affected driver awareness for visual and auditory stimuli, even those that were driving relevant and safety critical (e.g. pedestrians or the sound of a car horn). The results support load theory and suggest that perceptual load may be an important factor in driver safety.

The aim of the reported research was to examine the perceptions of road user safety amongst different road users and examine the link between attitudes, empathy and skill in motorcycle safety behaviour. Motorcyclists were perceived by the study participants, members of the public at four different locations at the UK (including motorcyclists and non-motorcyclists), as a group be at a high risk of accidents on the road. This was due to perceived behavioural characteristics of motorcyclists – who were viewed as ‘thrill seekers’ – as well as observed behaviours on the road. This, coupled with the physical vulnerability and excessive speeds, meant that motorbike driving was considered by the study participants as the least safe form of road use. There was broad agreement that motorcycling was dangerous as a whole, but not all motorcyclists were necessarily risky riders. The issue of ‘competitive space’ emerged between car drivers and motorcyclists in particular and it was suggested that there was a lack of mutual awareness and considerations between the two groups. Generally, greatest empathy comes from drivers who are motorcyclists themselves. Engineering, education, enforcement interventions were investigated. These were aimed at two main areas: normalising safer driving behaviours for motorcyclists and increasing awareness of bikes for motorists—particularly in relation to reducing speed limits at urban junctions. Finally, the idea of risk mapping and reduced speed limits on rural roads was seen as potentially effective—particularly as certain motorcyclists highlighted that they changed their riding behaviours by increasing speed and taking greater risks on these roads.

ABSTRACT Explaining how we attend to some objects and not others in real world environments remains a challenge for theories of attention. Driving is an ideal example of this, as it requires a complex synthesis of attentional processing, while still allowing attention to be captured by hazards. In the current study we employed a static inattentional blindness (IB) driving task in which participants were required to make decisions about the content of driving-related scenarios. In a critical trial, an additional stimulus was added to the driving scenario. All unexpected stimuli were thematically consistent with a normal driving environment but varied in their level of hazard threat. Rates of IB were consistent with the level of hazard threat of the stimuli. The results are discussed in terms of semantic-based attentional capture in driving, and models of IB.Copyright 2015 John Wiley & Sons, Ltd.

ooked-but-failed-to-see vehicle collisions occur when a driver gives all indications of having responsibly evaluated the driving situation yet still fails to see a hazard that is clearly in view. The experience maps well onto the psychological phenomenon called inattentional blindness (IB). IB occurs when a viewer fails to see an unexpected object that is clearly visible, particularly if they are concentrating on an additional primary task. In this study, a driving-related IB task was used to explore whether an unexpected stimulus (US) such as a pedestrian or animal, is more likely to be seen in country or city-related driving scenarios if it is congruent or incongruent with the semantic context of the scenes, and thus congruent or incongruent with the attentional set of the viewer. Overall, participants were more likely to see the US in the City scenarios, which also demonstrated a borderline effect of congruency, with incongruent stimuli less likely to be seen than congruent stimuli. Analyses suggested that driver experience was related to detection of the US in City scenarios but not Country scenarios. However, analyses also revealed that participants generally tended to drive in city rather than country environments, thus prompting speculation that the results may reflect attentional requirements for familiar and unfamiliar driving scenarios. Thus we suggest that the analysis of the driving situation, and the attentional set that we develop to filter information, change when the driving situation is more familiar.

Previous research has shown that changes to scenes are often surprisingly hard to detect. The research reported here investigated the relationship between individual differences in attention and change detection. We did this by assessing participant breadth of attention in a functional field of view task (FFOV) and relating this measure to the speed with which individuals detected changes in scenes. We also examined how the salience, meaningfulness, and eccentricity of the scene changes affected perceptual change performance. In order to broaden the range of individual differences in attentional breadth, both young and old adults participated in the study. A strong negative relationship was obtained between attentional breadth and the latency with which perceptual changes were detected; observers with broader attentional windows detected changes faster. Salience and eccentricity had large effects on change detection, but meaning aided the performance of young adults only and only when changes also had low salience.

The biased competition approach to visuo-spatial attention proposes that the selection of competing information is effected by the saliency of the stimulus as well as by an intention-based bias of attention towards behavioural goals. Wascher and Beste (2010) [32] showed that the detection of relevant information depends on its relative saliency compared to irrelevant conflicting stimuli. Furthermore the N1pc, N2pc and N2 of the EEG varied with the strength of the conflict. However, this system could also be modulated by rather global mechanisms like attentional effort. The present study investigates such modulations by testing the influence of extrinsic motivation on the selection of competing stimuli. Participants had to detect a luminance change in various conditions among others against an irrelevant orientation change. Half of the participants were motivated to maximize their performance by the announcement of a monetary reward for correct responses. Participants who were motivated had lower error rates than participants who were not motivated. The event-related lateralizations of the EEG showed no motivation-related effect on the N1pc, which reflects the initial saliency driven orientation of attention towards the more salient stimulus. The subsequent N2pc was enhanced in the motivation condition. Extrinsic motivation was also accompanied by enhanced fronto-central negativities. Thus, the data provide evidence that the improvement of selection performance when participants were extrinsically motivated by announcing a reward was not due to changes in the initial saliency based processing of information but was foremost mediated by improved higher-level mechanisms.

Right of way violation crashes are the most common type of accidents that motorcyclists face. This study assessed right of way decisions in scenarios which require noticing whether there is traffic from behind that is about to overtake. A test was created which presents participants clips with a wide field of vision (from a driver's perspective in a moving vehicle), with mirror information inset that allows either cars or motorcycles that are about to overtake, to be attended. Novice and experienced car drivers, and dual drivers (with both car and motorcycle experience), watched these clips while their eye movements were monitored. The results indicated that in the rear-view and the right-side mirrors, and in the right hand lane, conflicting motorcycles garnered more attention than conflicting cars. This pattern however was particularly driven by the dual drivers group. Additionally, novice drivers and dual drivers made more use of the right side mirror than the experienced drivers. Dual drivers also made more use of the rear view mirror than experienced drivers. Finally, significant positive correlations that were found between percentages of safe manoeuvres and measures of visual search provide direct evidence demonstrating that the frequency of risky manoeuvres was indeed larger in those cases where less time was spent gazing at the mirrors, indicating that the additional attention devoted to process conflicting vehicles contributes to reduce risky manoeuvres. The general pattern of results also provides some indirect support that non-motorcyclists drivers are more likely to have Look But Fail To See errors with conflicting motorcycles than motorcyclist drivers.

The highly task-specific fixation patterns revealed in performance of natural tasks demonstrate the fundamentally active nature of vision, and suggest that in many situations, top-down processes may be a major factor in the acquisition of visual information. Understanding how a top-down visual system could function requires understanding the mechanisms that control the initiation of the different task-specific computations at the appropriate time. This is particularly difficult in dynamic environments, like driving, where many aspects of the visual input may be unpredictable. We therefore examined drivers' abilities to detect Stop signs in a virtual environment when the signs were visible for restricted periods of time. Detection performance is heavily modulated both by the instructions and the local visual context. This suggests that visibility of the signs requires active search, and that the frequency of this search is influenced by learnt knowledge of the probabilistic structure of the environment.

With each eye fixation, we experience a richly detailed visual world. Yet recent work on visual integration and change direction reveals that we are surprisingly unaware of the details of our environment from one view to the next: we often do not detect large changes to objects and scenes ('change blindness'). Furthermore, without attention, we may not even perceive objects ('inattentional blindness'). Taken together, these findings suggest that we perceive and remember only those objects and details that receive focused attention. In this paper, we briefly review and discuss evidence for these cognitive forms of 'blindness'. We then present a new study that builds on classic studies of divided visual attention to examine inattentional blindness for complex objects and events in dynamic scenes. Our results suggest that the likelihood of noticing an unexpected object depends on the similarity of that object to other objects in the display and on how difficult the priming monitoring task is. Interestingly, spatial proximity of the critical unattended object to attended locations does not appear to affect detection, suggesting that observers attend to objects and events, not spatial positions. We discuss the implications of these results for visual representations and awareness of our visual environment.

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.Keywords: Driver distraction;

Since motorcyclists are over-involved in accidents, it is of some importance to determine whether or not the use of headlights during daylight might lead to a reduction in such accidents. While some U.S. states have laws in this regard, and other places including Australia have recommendations that such a policy become law, a study was made to help a decision as to whether or not the policy should be introduced into New Zealand. Studies reviewed included those of accident characteristics, those concerning daylight running-light use on automobiles, and those involving day time light use on motorcycles. Physiological and psychological reasons for conspieuity (or lack thereof) of an object are also reviewed, as are factors affecting perceptual processes. It is concluded that compulsory usage of motorcycle headlights should be favored and that New Zealand is very likely to have a benefit-cost ratio exceeding l if such a policy is adopted.

Objective:This study investigated variables that may contribute to motorcycle conspicuity within a high-fidelity simulated environment. The variables included motorcycle lighting, vehicular daytime running lights (DRLs), and age of the driver of the other vehicle.Background: Research suggests that decreased levels of conspicuity associated with riding a small two-wheeled vehicle reduce the ability of other drivers to detect and respond to that vehicle effectively. This lack of conspicuity is often responsible for the frequent injuries and fatalities incurred by motorcycle riders.Method: The 75 participants who took part in this study watched a series of video clips of roadway traffic and were asked to indicate when they saw a hazardous situation, such as the presence of pedestrians, motorcycles, or traffic cones. Both motorcycle and following-vehicle lights were manipulated, and participant reaction times were collected and analyzed.Results: Analyses indicated main effects for all three variables as well as interaction effects between motorcycle lighting and vehicle-following conditions. Overall, findings showed a link between DRLs and the effective detection of motorcycles and suggested that age-related changes affect the ability to detect and respond to a motorcycle effectively.Conclusion: Although our laboratory findings corroborated previous correlational studies, further research in real-world settings, such as those with high-density traffic or under adverse environmental conditions, needs to be conducted.Application: Potential applications of this research include the assessment of appropriate lighting technology to enhance conspicuity of motorcycles and reduce the high rate of fatalities and injuries related to motorcycle crashes.

Abstract Perhaps the most striking phenomenon of visual awareness is inattentional blindness (IB), in which a surprisingly salient event right in front of you may go completely unseen when unattended. Does IB reflect a failure of perception, or only of subsequent memory? Previous work has been unable to answer this question, due to a seemingly intractable dilemma: ruling out memory requires immediate perceptual reports, but soliciting such reports fuels an expectation that eliminates IB. Here we introduce a way of evoking repeated IB in the same subjects and the same session: we show that observers fail to report seeing salient events' not only when they have no expectation, but also when they have the wrong expectations about the events nature. This occurs when observers must immediately report seeing anything unexpected, even mid-event. Repeated IB thus demonstrates that IB is aptly named: it reflects a genuine deficit in moment-by-moment conscious perception, rather than a form of inattentional amnesia.

Objective To investigate whether the risk of motorcycle crash related injuries is associated with the conspicuity of the driver or vehicle. Design Population based case-control study. Setting Auckland region of New Zealand from February 1993 to February 1996. Participants 463 motorcycle drivers (cases) involved in crashes leading to hospital treatment or death; 1233 motorcycle drivers (controls) recruited from randomly selected roadside survey sites. Main outcome measures Estimates of relative risk of motorcycle crash related injury and population attributable risk associated with conspicuity measures, including the use of reflective or fluorescent clothing, headlight operation, and colour of helmet, clothing, and motorcycle. Results Crash related injuries occurred mainly in urban zones with 50 km/h speed limit (66%), during the day (63%), and in fine weather (72%). After adjustment for potential confounders, drivers wearing any reflective or fluorescent clothing had a 37% lower risk (multivariate odds ratio 0.63,95% confidence interval 0.42 to 0.94) than other drivers. Compared with wearing a black helmet, use of a white helmet was associated with a 24% lower risk (multivariate odds ratio 0.76,0.57 to 0.99). Self reported light coloured helmet versus dark coloured helmet was associated with a 19% lower risk. Three quarters of motorcycle riders had their headlight turned on during the day, and this was associated with a 27% lower risk (multivariate odds ratio 0.73,0.53 to 1.00). No association occurred between risk and the frontal colour of drivers' clothing or motorcycle. If these odds ratios are unconfounded, the population attributable risks are 33% for wearing no reflective or fluorescent clothing, 18% for a non-white helmet, 11% for a dark coloured helmet, and 7% for no daytime headlight operation. Conclusions Low conspicuity may increase the risk of motorcycle crash related injury. Increasing the use of reflective or fluorescent clothing, white or light coloured helmets, and daytime headlights are simple, cheap interventions that could considerably reduce motorcycle crash related injury and death.

vere injuries, as opposed to 14.1% of the automobile accidents (Appel, Otte, & Wiis- temann, 1986, p. 97). Taking into account miles of travel, the death rate in the U.S. for motorcycle riders of about 35 per 100,000,000 miles of travel contrasts with an overall motor vehicle death rate of 2.57 per 100,000,000 miles (National Safety Council, 1987). In West Germany, the death rate by kilometers traveled is 44 times higher for motorcyclists than for automobile driv- ers (Appel et al., 1986). Another illustration of the differing risks involved in riding a motorcycle or driving a car is presented in Table 1, which contains the average times and distances of travel until the occurrence of an accident resulting in an injury or a fatality.