Audiovisual spatial ventriloquism is reduced in musicians.

There is great scientific and public interest in claims that musical training improves general cognitive and perceptual abilities. While this is controversial, recent and rather convincing evidence suggests that musical training refines the temporal integration of auditory and visual stimuli at a general level. We investigated whether musical training also affects integration in the spatial domain, via an auditory localisation experiment that measured ventriloquism (where localisation is biased towards visual stimuli on audiovisual trials) and recalibration (a unimodal localisation aftereffect). While musicians (n = 22) and non-musicians (n = 22) did not have significantly different unimodal precision or accuracy, musicians were significantly less susceptible than non-musicians to ventriloquism, with large effect sizes. We replicated these results in another experiment with an independent sample of 24 musicians and 21 non-musicians. Across both experiments, spatial recalibration did not significantly differ between the groups even though musicians resisted ventriloquism. Our results suggest that the multisensory expertise afforded by musical training refines spatial integration, a process that underpins multisensory perception.

The relationship between central and mid-peripheral motion perception and the hazard perception test in younger and older adults.

INTRODUCTION: Vision standards for driving are typically based on visual acuity, despite evidence that it is a poor predictor of driving safety and performance. However, visual motion perception is potentially relevant for driving, as the vehicle and surroundings are in motion. This study explored whether tests of central and mid-peripheral motion perception better predict performance on a hazard perception test (HPT), which is related to driving performance and crash risk, than visual acuity. Additionally, we explored whether age influences these associations, as healthy ageing impairs performance on some motion sensitivity tests. METHODS: Sixty-five visually healthy drivers (35 younger, mean age: 25.5; SD 4.3 years; 30 older adults, mean age: 71.0; SD 5.4 years) underwent a computer-based HPT, plus four different motion sensitivity tests both centrally and at 15° eccentricity. Motion tests included minimum displacement to identify motion direction (Dmin ), contrast detection threshold for a drifting Gabor (motion contrast), coherence threshold for a translational global motion stimulus and direction discrimination for a biological motion stimulus in the presence of noise. RESULTS: Overall, HPT reaction times were not significantly different between age groups (p = 0.40) nor were maximum HPT reaction times (p = 0.34). HPT response time was associated with motion contrast and Dmin centrally (r = 0.30, p = 0.02 and r = 0.28, p = 0.02, respectively) and with Dmin peripherally (r = 0.34, p = 0.005); these associations were not affected by age group. There was no significant association between binocular visual acuity and HPT response times (r = 0.02, p = 0.29). CONCLUSIONS: Some measures of motion sensitivity in central and mid-peripheral vision were associated with HPT response times, whereas binocular visual acuity was not. Peripheral testing did not show an advantage over central testing for visually healthy older drivers. Our findings add to the growing body of evidence that the ability to detect small motion changes may have potential to identify unsafe road users.

The song that never ends: The effect of repeated exposure on the development of an earworm.

An "earworm"-the experience of a catchy melody that repeats persistently in the mind-is a ubiquitous yet mysterious cognitive phenomenon. Previous research demonstrates that earworms for vocal music engage working memory resources, manifesting as "inner singing." This study investigated whether this effect is moderated by prior exposure to music. In one experimental session, participants (N = 44) were presented with four novel song choruses. To manipulate exposure, each song was presented between one and four times, counterbalanced across participants. The following day, participants undertook a serial recall task during and following presentation of each song. In addition, they rated the music on familiarity, enjoyment, their desire to sing along, and perceived catchiness, both before and following the experiment. Increased exposure to novel songs on the first day tended to result in greater interference on task performance during and following their presentation on the second day, yet the effect varied depending on the song. Ratings of the desire to sing along and perceived familiarity increased significantly between the sessions for all songs. These findings are important in understanding the relative influence of familiarity and song-level characteristics on the development of an earworm.

Musical training refines audiovisual integration but does not influence temporal recalibration.

When the brain is exposed to a temporal asynchrony between the senses, it will shift its perception of simultaneity towards the previously experienced asynchrony (temporal recalibration). It is unknown whether recalibration depends on how accurately an individual integrates multisensory cues or on experiences they have had over their lifespan. Hence, we assessed whether musical training modulated audiovisual temporal recalibration. Musicians (n = 20) and non-musicians (n = 18) made simultaneity judgements to flash-tone stimuli before and after adaptation to asynchronous (± 200 ms) flash-tone stimuli. We analysed these judgements via an observer model that described the left and right boundaries of the temporal integration window (decisional criteria) and the amount of sensory noise that affected these judgements. Musicians' boundaries were narrower (closer to true simultaneity) than non-musicians', indicating stricter criteria for temporal integration, and they also exhibited enhanced sensory precision. However, while both musicians and non-musicians experienced cumulative and rapid recalibration, these recalibration effects did not differ between the groups. Unexpectedly, cumulative recalibration was caused by auditory-leading but not visual-leading adaptation. Overall, these findings suggest that the precision with which observers perceptually integrate audiovisual temporal cues does not predict their susceptibility to recalibration.

Does Online Social Connectedness Buffer Risk of Depression Following Driving Cessation? An Analysis of Older Drivers and Ex-Drivers.

This study investigates the role of online social connectedness as a buffer against depression in older adults who cease driving. A survey of 108 over-65 year olds (M = 73.7, SD = 7.37) was conducted. Measures included online and offline social connectedness; depression; online activities; and general health. The online activities in which older adults most frequently engaged were communicating with family and friends, reading the news, and banking. Face-to-face social connectedness was by far the strongest predictor of depression. However, online social connectedness did significantly moderate the effects of driving cessation on depression. The results suggest that online social connectedness can help protect older people from depressive symptoms following driving cessation.

Night-time pedestrian conspicuity: effects of clothing on drivers' eye movements.

PURPOSE: Drivers' responses and eye movements were assessed as they approached pedestrians at night in order to explore the relative conspicuity benefits of different configurations of retroreflective markings. METHODS: Eye movements were recorded using an ASL Mobile Eye (Applied Science Technologies, www.asleyetracking.com) from 14 young licensed drivers (M = 24.1 ± 6.4 years) as they drove along a closed-road circuit at night. At two locations, pedestrians walked in place facing either towards or away from the road. Pedestrians wore black clothing with a standard retroreflective vest either alone or with additional retroreflective markers positioned in a configuration conveying biological motion (biomotion). Drivers responded when they recognised that a pedestrian was present and again when they identified the direction the pedestrian was facing. RESULTS: Drivers recognised pedestrians from a significantly greater distance (p < 0.05) when the pedestrian's clothing included the biomotion configuration (319.1 m) than when the biomotion markings were absent (184.5 m). Further, the drivers recognised the direction that the pedestrian faced from a longer distance when biomotion markings were present (215.4 m vs 95.6 m). Eye movement data suggested that the biomotion configuration attracted drivers' attention significantly sooner than the vest (time to first fixation: 1.1 vs 3.5 s), that drivers fixated on pedestrians wearing biomotion for significantly less time prior to responding (3.4 s vs 6.1 s), and the time to first recognise a pedestrian was approximately half that for biomotion compared to vest (6.4 vs 13.9 s). CONCLUSION: Adding biomotion reflectors to the vest facilitated earlier recognition of pedestrians and faster identification of the direction that the pedestrian faced. These findings confirm that the conspicuity advantages of biomotion configurations on pedestrians at night result in part from drivers fixating pedestrians earlier and more efficiently.

Do Learned Alarm Sounds Interfere With Working Memory?

OBJECTIVE: To assess whether identifying (or ignoring) learned alarm sounds interferes with performance on a task involving working memory. BACKGROUND: A number of researchers have suggested that auditory alarms could interfere with working memory in complex task environments, and this could serve as a caution against their use. Changing auditory information has been shown to interfere with serial recall, even when the auditory information is to be ignored. However, previous researchers have not examined well-learned patterns, such as familiar alarms. METHOD: One group of participants learned a set of alarms (either a melody, a rhythmic pulse, or a spoken nonword phrase) and subsequently undertook a digits-forward task in three conditions (no alarms, identify the alarm, or ignore the alarm). A comparison group undertook the baseline and ignore conditions but had no prior exposure to the alarms. RESULTS: All alarms interfered with serial recall when participants were asked to identify them; however, only the nonword phrase interfered with recall when ignored. Moreover, there was no difference between trained and untrained participants in terms of recall performance when ignoring the alarms, suggesting that previous training does not make alarms less ignorable. CONCLUSION: Identifying any alarm sound may interfere with immediate working memory; however, spoken alarms may interfere even when ignored. APPLICATION: It is worth considering the importance of alarms in environments requiring high working memory performance and in particular avoiding spoken alarms in such environments.

Eye Movements and Road Hazard Detection: Effects of Blur and Distractors.

PURPOSE: To examine the effects of optical blur, auditory distractors, and age on eye movement patterns while performing a driving hazard perception test (HPT). METHODS: Twenty young (mean age 27.1 ± 4.6 years) and 20 older (73.3 ± 5.7 years) drivers with normal vision completed a HPT in a repeated-measures counterbalanced design while their eye movements were recorded. Testing was performed under two visual (best-corrected vision and with +2.00DS blur) and two distractor (with and without auditory distraction) conditions. Participants were required to respond to road hazards appearing in the HPT videos of real-world driving scenes and their hazard response times were recorded. RESULTS: Blur and distractors each significantly delayed hazard response time by 0.42 and 0.76 s, respectively (p < 0.05). A significant interaction between age and distractors indicated that older drivers were more affected by distractors than young drivers (response with distractors delayed by 0.96 and 0.60 s, respectively). There were no other two- or three-way interaction effects on response time. With blur, for example, both groups fixated significantly longer on hazards before responding compared to best-corrected vision. In the presence of distractors, both groups exhibited delayed first fixation on the hazards and spent less time fixating on the hazards. There were also significant differences in eye movement characteristics between groups, where older drivers exhibited smaller saccades, delayed first fixation on hazards, and shorter fixation duration on hazards compared to the young drivers. CONCLUSIONS: Collectively, the findings of delayed hazard response times and alterations in eye movement patterns with blur and distractors provide further evidence that visual impairment and distractors are independently detrimental to driving safety given that delayed hazard response times are linked to increased crash risk.

When and Why Threats Go Undetected: Impacts of Event Rate and Shift Length on Threat Detection Accuracy During Airport Baggage Screening.

OBJECTIVE: We aimed to assess the impact of task demands and individual characteristics on threat detection in baggage screeners. BACKGROUND: Airport security staff work under time constraints to ensure optimal threat detection. Understanding the impact of individual characteristics and task demands on performance is vital to ensure accurate threat detection. METHOD: We examined threat detection in baggage screeners as a function of event rate (i.e., number of bags per minute) and time on task across 4 months. We measured performance in terms of the accuracy of detection of Fictitious Threat Items (FTIs) randomly superimposed on X-ray images of real passenger bags. RESULTS: Analyses of the percentage of correct FTI identifications (hits) show that longer shifts with high baggage throughput result in worse threat detection. Importantly, these significant performance decrements emerge within the first 10 min of these busy screening shifts only. CONCLUSION: Longer shift lengths, especially when combined with high baggage throughput, increase the likelihood that threats go undetected. APPLICATION: Shorter shift rotations, although perhaps difficult to implement during busy screening periods, would ensure more consistently high vigilance in baggage screeners and, therefore, optimal threat detection and passenger safety.

Effects of Different Levels of Refractive Blur on Nighttime Pedestrian Visibility.

PURPOSE: The aim of this study was to systematically investigate the effect of different levels of refractive blur and driver age on nighttime pedestrian recognition and determine whether clothing that has been shown to improve pedestrian conspicuity is robust to the effects of blur. METHODS: Nighttime pedestrian recognition was measured for 24 visually normal participants (12 younger mean = 24.9 ± 4.5 years and 12 older adults mean = 77.6 ± 5.7 years) for three levels of binocular blur (+0.50 diopter [D], +1.00 D, +2.00 D) compared with baseline (optimal refractive correction). Pedestrians walked in place on a closed road circuit and wore one of three clothing conditions: everyday clothing, a retro-reflective vest, and retro-reflective tape positioned on the extremities in a configuration that conveyed biological motion (known as "biomotion"); the order of conditions was randomized among participants. Pedestrian recognition distances were recorded for each blur and pedestrian clothing combination while participants drove an instrumented vehicle around a closed road course. RESULTS: The recognition distances for pedestrians were significantly reduced (P < 0.05) by all levels of blur compared with baseline. Pedestrians wearing biomotion clothing were recognized at significantly longer distances than for the other clothing configurations in all blur conditions. However, these effects were smaller for the older adults, who had much shorter recognition distances for all conditions tested. CONCLUSIONS: In summary, even small amounts of blur had a significant detrimental effect on nighttime pedestrian recognition. Biomotion retro-reflective clothing was effective, even under moderately degraded visibility conditions, for both young and older drivers.

Seeing pedestrians at night: effect of driver age and visual abilities.

PURPOSE: To quantify the effects of driver age on night-time pedestrian conspicuity, and to determine whether individual differences in visual performance can predict drivers' ability to recognise pedestrians at night. METHODS: Participants were 32 visually normal drivers (20 younger: M = 24.4 years ± 6.4 years; 12 older: M = 72.0 years ± 5.0 years). Visual performance was measured in a laboratory-based testing session including visual acuity, contrast sensitivity, motion sensitivity and the useful field of view. Night-time pedestrian recognition distances were recorded while participants drove an instrumented vehicle along a closed road course at night; to increase the workload of drivers, auditory and visual distracter tasks were presented for some of the laps. Pedestrians walked in place, sideways to the oncoming vehicles, and wore either a standard high visibility reflective vest or reflective tape positioned on the movable joints (biological motion). RESULTS: Driver age and pedestrian clothing significantly (p < 0.05) affected the distance at which the drivers first responded to the pedestrians. Older drivers recognised pedestrians at approximately half the distance of the younger drivers and pedestrians were recognised more often and at longer distances when they wore a biological motion reflective clothing configuration than when they wore a reflective vest. Motion sensitivity was an independent predictor of pedestrian recognition distance, even when controlling for driver age. CONCLUSIONS: The night-time pedestrian recognition capacity of older drivers was significantly worse than that of younger drivers. The distance at which drivers first recognised pedestrians at night was best predicted by a test of motion sensitivity.

Age-related changes in perception of movement in driving scenes.

PURPOSE: Age-related changes in motion sensitivity have been found to relate to reductions in various indices of driving performance and safety. The aim of this study was to investigate the basis of this relationship in terms of determining which aspects of motion perception are most relevant to driving. METHODS: Participants included 61 regular drivers (age range 22-87 years). Visual performance was measured binocularly. Measures included visual acuity, contrast sensitivity and motion sensitivity assessed using four different approaches: (1) threshold minimum drift rate for a drifting Gabor patch, (2) Dmin from a random dot display, (3) threshold coherence from a random dot display, and (4) threshold drift rate for a second-order (contrast modulated) sinusoidal grating. Participants then completed the Hazard Perception Test (HPT) in which they were required to identify moving hazards in videos of real driving scenes, and also a Direction of Heading task (DOH) in which they identified deviations from normal lane keeping in brief videos of driving filmed from the interior of a vehicle. RESULTS: In bivariate correlation analyses, all motion sensitivity measures significantly declined with age. Motion coherence thresholds, and minimum drift rate threshold for the first-order stimulus (Gabor patch) both significantly predicted HPT performance even after controlling for age, visual acuity and contrast sensitivity. Bootstrap mediation analysis showed that individual differences in DOH accuracy partly explained these relationships, where those individuals with poorer motion sensitivity on the coherence and Gabor tests showed decreased ability to perceive deviations in motion in the driving videos, which related in turn to their ability to detect the moving hazards. CONCLUSIONS: The ability to detect subtle movements in the driving environment (as determined by the DOH task) may be an important contributor to effective hazard perception, and is associated with age, and an individuals' performance on tests of motion sensitivity. The locus of the processing deficits appears to lie in first-order, rather than second-order motion pathways.

Configuring retroreflective markings to enhance the night-time conspicuity of road workers.

This study investigated whether the night-time conspicuity of road workers can be enhanced by positioning retroreflective strips on the moveable joints in patterns that convey varying degrees of biological motion. Participants were 24 visually normal adults (12 young M=26.8 years; 12 older M=72.9 years). Visual acuity, contrast sensitivity and glare sensitivity were recorded for each participant. Experimenters acting as road workers walked in place on a closed road circuit within simulated road work sites, facing either the oncoming driver or the roadway (presenting sideways to the driver) and wearing one of four clothing conditions: (i) standard road worker vest; (ii) standard vest plus thigh-mounted retroreflective strips; (iii) standard vest plus retroreflective strips on ankles and knees; (iv) standard vest plus retroreflective strips positioned on the extremities in a configuration that conveyed biological motion ("biomotion"). As they drove along the closed road participants were instructed to press a button to indicate when they first recognized that a road worker was present. The results demonstrated that regardless of the direction of walking, road workers wearing biomotion clothing were recognized at significantly (p<0.05) longer distances (3×), relative to the standard vest alone. Response distances were significantly shorter for the older drivers. Contrast sensitivity was a better predictor of the ability to recognize road workers than was visual acuity or glare sensitivity. We conclude that adding retroreflective strips in the biomotion configuration can significantly improve road worker conspicuity regardless of the road worker's orientation and the age of the driver.

Differential effects of refractive blur on day and nighttime driving performance.

PURPOSE: To investigate the effect of different levels of refractive blur on real-world driving performance measured under day and nighttime conditions. METHODS: Participants included 12 visually normal, young adults (mean age = 25.8 ± 5.2 years) who drove an instrumented research vehicle around a 4 km closed road circuit with three different levels of binocular spherical refractive blur (+0.50 diopter sphere [DS], +1.00 DS, +2.00 DS) compared with a baseline condition. The subjects wore optimal spherocylinder correction and the additional blur lenses were mounted in modified full-field goggles; the order of testing of the blur conditions was randomized. Driving performance was assessed in two different sessions under day and nighttime conditions and included measures of road signs recognized, hazard detection and avoidance, gap detection, lane-keeping, sign recognition distance, speed, and time to complete the course. RESULTS: Refractive blur and time of day had significant effects on driving performance (P < 0.05), where increasing blur and nighttime driving reduced performance on all driving tasks except gap judgment and lane keeping. There was also a significant interaction between blur and time of day (P < 0.05), such that the effects of blur were exacerbated under nighttime driving conditions; performance differences were evident even for +0.50 DS blur relative to baseline for some measures. CONCLUSIONS: The effects of blur were greatest under nighttime conditions, even for levels of binocular refractive blur as low as +0.50 DS. These results emphasize the importance of accurate and up-to-date refractive correction of even low levels of refractive error when driving at night.

Visual motion perception predicts driving hazard perception ability.

PURPOSE: To examine the basis of previous findings of an association between indices of driving safety and visual motion sensitivity and to examine whether this association could be explained by low-level changes in visual function. METHODS: A total of 36 visually normal participants (aged 19-80 years) completed a battery of standard vision tests including visual acuity, contrast sensitivity and automated visual fields and two tests of motion perception including sensitivity for movement of a drifting Gabor stimulus and sensitivity for displacement in a random dot kinematogram (Dmin ). Participants also completed a hazard perception test (HPT), which measured participants' response times to hazards embedded in video recordings of real-world driving, which has been shown to be linked to crash risk. RESULTS: Dmin for the random dot stimulus ranged from -0.88 to -0.12 log minutes of arc, and the minimum drift rate for the Gabor stimulus ranged from 0.01 to 0.35 cycles per second. Both measures of motion sensitivity significantly predicted response times on the HPT. In addition, while the relationship involving the HPT and motion sensitivity for the random dot kinematogram was partially explained by the other visual function measures, the relationship with sensitivity for detection of the drifting Gabor stimulus remained significant even after controlling for these variables. CONCLUSION: These findings suggest that motion perception plays an important role in the visual perception of driving-relevant hazards independent of other areas of visual function and should be further explored as a predictive test of driving safety. Future research should explore the causes of reduced motion perception to develop better interventions to improve road safety.

Sensorimotor and postural control factors associated with driving safety in a community-dwelling older driver population.

BACKGROUND: To establish whether sensorimotor function and balance are associated with on-road driving performance in older adults. METHODS: The performance of 270 community-living adults aged 70-88 years recruited via the electoral roll was measured on a battery of peripheral sensation, strength, flexibility, reaction time, and balance tests and on a standardized measure of on-road driving performance. RESULTS: Forty-seven participants (17.4%) were classified as unsafe based on their driving assessment. Unsafe driving was associated with reduced peripheral sensation, lower limb weakness, reduced neck range of motion, slow reaction time, and poor balance in univariate analyses. Multivariate logistic regression analysis identified poor vibration sensitivity, reduced quadriceps strength, and increased sway on a foam surface with eyes closed as significant and independent risk factors for unsafe driving. These variables classified participants into safe and unsafe drivers with a sensitivity of 74% and specificity of 70%. CONCLUSIONS: A number of sensorimotor and balance measures were associated with driver safety and the multivariate model comprising measures of sensation, strength, and balance was highly predictive of unsafe driving in this sample. These findings highlight important determinants of driver safety and may assist in developing efficacious driver safety strategies for older drivers.

Vision in water.

The purpose of this study is to determine visual performance in water, including the influence of pupil size. The water environment was simulated by placing goggles filled with saline in front of the eyes with apertures placed at the front of the goggles. Correction factors were determined for the different magnification under this condition in order to estimate vision in water. Experiments were conducted on letter visual acuity (seven participants), grating resolution (eight participants), and grating contrast sensitivity (one participant). For letter acuity, mean loss of vision in water, compared to corrected vision in air, varied between 1.1 log min of arc resolution (logMAR) for a 1 mm aperture to 2.2 logMAR for a 7 mm aperture. The vision in min of arc was described well by a linear relationship with pupil size. For grating acuity, mean loss varied between 1.1 logMAR for a 2 mm aperture to 1.2 logMAR for a 6 mm aperture. Contrast sensitivity for a 2 mm aperture deteriorated as spatial frequency increased with a 2 log unit loss by 3 c/°. Superimposed on this deterioration were depressions (notches) in sensitivity with the first three notches occurring at 0.45, 0.8, and 1.3 c/° with estimates for water of 0.39, 0.70, and 1.13 c/°. In conclusion, vision in water is poor. It becomes worse as pupil size increases, but the effects are much more marked for letter targets than for grating targets.

Bicyclists overestimate their own night-time conspicuity and underestimate the benefits of retroreflective markers on the moveable joints.

Conspicuity limitations make bicycling at night dangerous. This experiment quantified bicyclists' estimates of the distance at which approaching drivers would first recognize them. Twenty five participants (including 13 bicyclists who rode at least once per week, and 12 who rode once per month or less) cycled in place on a closed-road circuit at night-time and indicated when they were confident that an approaching driver would first recognize that a bicyclist was present. Participants wore black clothing alone or together with a fluorescent bicycling vest, a fluorescent bicycling vest with additional retroreflective tape, or the fluorescent retroreflective vest plus ankle and knee reflectors in a modified 'biomotion' configuration. The bicycle had a light mounted on the handlebars which was either static, flashing or off. Participants judged that black clothing made them least visible, retroreflective strips on the legs in addition to a retroreflective vest made them most visible and that adding retroreflective materials to a fluorescent vest provides no conspicuity benefits. Flashing bicycle lights were associated with higher conspicuity than static lights. Additionally, occasional bicyclists judged themselves to be more visible than did frequent bicyclists. Overall, bicyclists overestimated their conspicuity compared to previously collected recognition distances and underestimated the conspicuity benefits of retroreflective markings on their ankles and knees. Participants mistakenly judged that a fluorescent vest that did not include retroreflective material would enhance their night-time conspicuity. These findings suggest that bicyclists have dangerous misconceptions concerning the magnitude of the night-time conspicuity problem and the potential value of conspicuity treatments.

A yellow filter improves response times to low-contrast targets and traffic hazards.

PURPOSE: Anecdotal evidence suggests that some sunglass users prefer yellow tints for outdoor activities, such as driving, and research has suggested that such tints improve the apparent contrast and brightness of real-world objects. The aim of this study was to establish whether yellow filters resulted in objective improvements in performance for visual tasks relevant to driving. METHODS: Response times of nine young (age [mean ± SD], 31.4 ± 6.7 years) and nine older (age, [mean ± SD], 74.6 ± 4.8) adults were measured using video presentations of traffic hazards (driving hazard perception task) and a simple low-contrast grating appeared at random peripheral locations on a computer screen. Response times were compared when participants wore a yellow filter (with and without a linear polarizer) versus a neutral density filter (with and without a linear polarizer). All lens combinations were matched to have similar luminance transmittances (~27%). RESULTS: In the driving hazard perception task, the young but not the older participants responded significantly more rapidly to hazards when wearing a yellow filter than with a luminance-matched neutral density filter (mean difference, 450 milliseconds). In the low-contrast grating task, younger participants also responded more quickly for the yellow filter condition but only when combined with a polarizer. Although response times increased with increasing stimulus eccentricity for the low-contrast grating task, for the younger participants, this slowing of response times with increased eccentricity was reduced in the presence of a yellow filter, indicating that perception of more peripheral objects may be improved by this filter combination. CONCLUSIONS: Yellow filters improve response times for younger adults for visual tasks relevant to driving.

Not all older adults have insight into their driving abilities: evidence from an on-road assessment and implications for policy.

PURPOSE: To compare self-reported driving ability with objective measures of on-road driving performance in a large cohort of older drivers. METHODS: Two hundred and seventy community-living adults aged 70-88 years recruited via the electoral roll completed a standardized assessment of on-road driving performance and questionnaires determining perceptions of their own driving ability, confidence, and driving difficulties. Retrospective self-reported crash data over the previous 5 years were recorded. RESULTS: Participants reported difficulty with only selected driving situations, including driving into the sun, in unfamiliar areas, in wet conditions, and at night or dusk. The majority of participants rated their own driving as good to excellent. Of the 47 (17%) drivers who were rated as potentially unsafe to drive, 66% rated their own driving as good to excellent. Drivers who made critical errors, where the driving instructor had to take control of the vehicle, had no lower self-rating of driving ability than the rest of the group. The discrepancy in self-perceptions of driving ability and participants' safety rating on the on-road assessment was significantly associated with self-reported retrospective crash rates, where those drivers who displayed greater overconfidence in their own driving were significantly more likely to report a crash. CONCLUSIONS: This study demonstrates that older drivers with the greatest mismatch between actual and self-rated driving ability pose the greatest risk to road safety. Therefore, licensing authorities should not assume that when older individuals' driving abilities begin to decline they will necessarily be aware of these changes and adopt appropriate compensatory driving behaviors; rather, it is essential that evidence-based assessments are adopted.