Monica N. Lees

The influence of distraction and driving context on driver response to imperfect collision warning systems.

Automotive collision warning systems (CWS) can enhance hazard identification and management. However, false alarms (FAs), which occur as a random activation of the system not corresponding to a threat and not interpretable by the driver, and unnecessary alarms (UAs), which occur in situations judged hazardous by the algorithm but not by the driver, may limit CWS effectiveness. A driving simulator was used to investigate the influence of CWS (accurate, UA, FA, none) and distraction on driver performance during non-critical and critical events. FAs and UAs differentially influenced trust and compliance. FAs diminished trust and compliance, whereas the context associated with UAs fostered trust and compliance during subsequent events. This study suggests current warning descriptions based on signal detection theory need to be expanded to represent how different types of alarms affect drivers.

Risky car following in abstinent users of MDMA

Ecstasy (MDMA) use raises concerns because of its association with risky driving. We evaluated driving performance and risk taking in abstinent recreational MDMA users in a simulated car following task that required continuous attention and vigilance. Drivers were asked to follow two car lengths behind a lead vehicle (LV). Three sinusoids generated unpredictable LV velocity changes. Drivers could mitigate risk by following further behind the erratic LV. From vehicle trajectory data we performed a Fourier analysis to derive measures of coherence, gain, and delay. These measures and headway distance were compared between the different groups. All MDMA drivers met coherence criteria indicating cooperation in the car following task. They matched periodic changes in LV velocity similar to controls (abstinent THC users, abstinent alcohol users, and non-drug users), militating against worse vigilance. While all participants traveled approximately 55 mph (89 kph), the MDMA drivers followed 64 m closer to the LV and demonstrated 1.04 s shorter delays to LV velocity changes than other driver groups. The simulated car following task safely discriminated between driving behavior in abstinent MDMA users and controls. Abstinent MDMA users do not perform worse than controls, but may assume extra risk. The control theory framework used in this study revealed behaviors that might not otherwise be evident.

Impaired Attentional Disengagement in Older Adults With Useful Field of View Decline

OBJECTIVES Typical measures of the useful field of view (UFOV) involve many components of attention. The objective of the current research was to examine the attentional operations that might underlie declines in the UFOV. METHOD AND RESULTS We used 2 basic attention tasks to characterize the profile of visual attention in UFOV-impaired and -unimpaired observers. Our results suggested that declines in the UFOV result from a deficit in attentional disengagement, not a decrease in attentional breadth or scope. DISCUSSION The results suggested that UFOV decline in normal aging can be associated with a specific attentional operation, namely attentional disengagement. These results suggest that the underlying cause of UFOV decline may not be a restriction in the breadth or scope of attention. Because the UFOV is a reliable predictor of driving safety, our results point to attentional components that are critical for the visual behavior of older adults.

Cross-modal Warnings for Orienting Attention in Older Drivers with and without Attention Impairments

Older adults are overrepresented in fatal crashes on a per-mile basis. Those with useful field of view (UFOV) reductions show a particularly elevated crash risk that might be mitigated with vehicle-based warnings. To evaluate cross-modal cues that could be used in these warnings, we applied a variation of Posners orienting of attention paradigm. Twenty-nine older drivers with UFOV impairments and 32 older drivers without impairments participated. Cues were presented in either a single modality or a combination of modalities (visual, auditory, haptic). Drivers experienced three cue types (valid spatial information, invalid spatial information, neutral) and an uncued baseline. Following each cue, drivers discriminated the direction of a target (a Landolt square with a gap facing up or down) in the visual panorama. Drivers with and without UFOV impairments showed comparable response times (RTs) across the different cue modalities and cue types. Both groups benefited most from auditory and auditory/haptic cues. Redundant visual cues, when paired with auditory cues, undermined performance rather than enhanced it. Overall, drivers responded faster to targets with valid spatial information followed by neutral, invalid, and uncued targets. Cues provide the greatest benefit in alerting rather than orienting the driver. The cue expected to be most effective at orienting attention - the extra-vehicular cue - performs most poorly when the spatial information is either invalid or neutral. Even when the spatial information is valid the extra-vehicular cue underperforms the auditory cues. The results suggest that temporal information dominates spatial information in the ability of cues to speed responses to targets. This study represents a first step in assessing whether combining a cognitive science paradigm and a driving simulator environment can quickly assess how different warning signals alert and orient drivers.

Visual Search for Features and Conjunctions Following Declines in the Useful Field of View

Background/Study Context: Typical measures for assessing the useful field (UFOV) of view involve many components of attention. The objective of the current experiment was to examine differences in visual search efficiency for older individuals with and without UFOV impairment. Methods: The authors used a computerized screening instrument to assess the useful field of view and to characterize participants as having an impaired or normal UFOV. Participants also performed two visual search tasks, a feature search (e.g., search for a green target among red distractors) or a conjunction search (e.g., a green target with a gap on its left or right side among red distractors with gaps on the left or right and green distractors with gaps on the top or bottom). Results: Visual search performance did not differ between UFOV impaired and unimpaired individuals when searching for a basic feature. However, search efficiency was lower for impaired individuals than unimpaired individuals when searching for a conjunction of features. Conclusion: The results suggest that UFOV decline in normal aging is associated with conjunction search. This finding suggests that the underlying cause of UFOV decline may arise from an overall decline in attentional efficiency. Because the useful field of view is a reliable predictor of driving safety, the results suggest that decline in the everyday visual behavior of older adults might arise from attentional declines.