Visual and cognitive demands of manual and voice-based driving mode implementations on smartphones.

Mobile phone apps and operating systems are increasingly adopting driving mode functions that attempt to reduce driver visual and cognitive demand by limiting functionality, using larger buttons and icons, and adding voice-based interactions. The present study assessed the visual and cognitive demands and the subjective level of distraction from two driving mode implementations (voice or manual) on an Android™ mobile phone using Google Assistant™, compared to a typical mobile phone operating system experience. While driving on a test track, participants performed several trials of five tasks on each of three interfaces: A mobile operating system interface, a manual driving mode interface, and a voice driving mode interface. Visual demand was measured with eye-gaze recordings, cognitive load was measured with the detection response task, and a Likert scale was used to rate the perceived level of distraction. The voice driving mode resulted in the lowest visual attention demand and lowest subjective ratings of distraction. The manual driving mode condition also reduced visual demand and subjective ratings of distraction relative to the mobile operating system condition. The cognitive load results were inconsistent across the task and interaction mode conditions. Overall, the results of this study provide positive evidence in support of voice-based driving mode implementations for reducing visual demand and subjective levels of distraction from mobile devices while driving. Moreover, the results suggest that manual driving mode implementations also have the potential to reduce visual demand and subjective levels of distraction, relative to the mobile operating system condition.

The Roelofs and induced Roelofs effects.

The visual image provides important cues for an observer's sense of location and orientation within the world. Occasionally, though, these cues can be misleading, resulting in illusions. In the Roelofs and induced Roelofs effects, for example, a large illuminated frame, offset from the observer's midline in otherwise complete darkness, tends to bias the observer's judgment of straight ahead, causing the position of the frame, and anything contained within it, to be misperceived. Studies of these illusions have provided much insight into the processes that establish an observer's egocentric reference frame, and the manner in which object locations are encoded relative to this frame for perception and action.

Active Listening Delays Attentional Disengagement and Saccadic Eye Movements.

Successful goal-directed visual behavior depends on efficient disengagement of attention. Attention must be withdrawn from its current focus before being redeployed to a new object or internal process. Previous research has demonstrated that occupying cognitive processes with a secondary cellular phone conversation impairs attentional functioning and driving behavior. For example, attentional processing is significantly impacted by concurrent cell phone use, resulting in decreased explicit memory for on-road information. Here, we examined the impact of a critical component of cell-phone use-active listening-on the effectiveness of attentional disengagement. In the gap task-a saccadic manipulation of attentional disengagement-we measured saccade latencies while participants performed a secondary active listening task. Saccadic latencies significantly increased under an active listening load only when attention needed to be disengaged, indicating that active listening delays a disengagement operation. Simple dual-task interference did not account for the observed results. Rather, active cognitive engagement is required for measurable disengagement slowing to be observed. These results have implications for investigations of attention, gaze behavior, and distracted driving. Secondary tasks such as active listening or cell-phone conversations can have wide-ranging impacts on cognitive functioning, potentially impairing relatively elementary operations of attentional function, including disengagement.

Texting during stair negotiation and implications for fall risk.

BACKGROUND/AIM: Walking requires the integration of the sensory and motor systems. Cognitive distractions have been shown to interfere with negotiation of complex walking environments, especially in populations at greater risk for falls (e.g. the elderly). With the pervasiveness of mobile messaging and the recent introduction of augmented reality mobile gaming, it is increasingly important to understand how distraction associated with the simultaneous use of a mobile device impacts navigation of the complex walking environments experienced in daily life. In this study, we investigated how gait kinematics were altered when participants performed a texting task during step negotiation. METHODS: Twenty participants (13 female, 7 males) performed a series of walking trials involving a step-deck obstacle, consisting of at least 3 texting trials and 3 non-texting trials. RESULTS: When texting, participants ascended more slowly and demonstrated reduced dual-step foot toe clearance. Participants similarly descended more slowly when texting and demonstrated reduced single-step foot heel clearance as well as reduced dual-step foot fore-aft heel clearance. CONCLUSION: These data support the conclusion that texting during stair negotiation results in changes to gait kinematics that may increase the potential for gait disruptions, falls, and injury. Further research should examine the effect texting has on performing other common complex locomotor tasks, actual fall risk, and the patterns of resulting injury rate and severity when negotiating complex environments.

Individual differences in cognitive functioning predict effectiveness of a heads-up lane departure warning for younger and older drivers.

The effectiveness of an idealized lane departure warning (LDW) was evaluated in an interactive fixed base driving simulator. Thirty-eight older (mean age=77years) and 40 younger drivers (mean age=35years) took four different drives/routes similar in road culture composition and hazards encountered with and without LDW. The four drives were administered over visits separated approximately by two weeks to examine changes in long-term effectiveness of LDW. Performance metrics were number of LDW activations and average correction time to each LDW. LDW reduced correction time to re-center the vehicle by 1.34s on average (95% CI=1.12-1.57s) but did not reduce the number of times the drivers drifted enough in their lanes to activate the system (LDW activations). The magnitude of reductions in average correction RT was similar for older and younger drivers and did not change with repeated exposures across visits. The contribution of individual differences in basic visual and motor function, as well as cognitive function to safety gains from LDW was also examined. Cognitive speed of processing predicted lane keeping performance for older and younger drivers. Differences in memory, visuospatial construction, and executive function tended to predict performance differences among older but not younger drivers. Cognitive functioning did not predict changes in the magnitude of safety benefits from LDW over time. Implications are discussed with respect to real-world safety systems.

PILOT RESULTS ON FORWARD COLLISION WARNING SYSTEM EFFECTIVENESS IN OLDER DRIVERS.

Advanced Driver Assistance Systems (ADAS) have largely been developed with a "one-size-fits-all" approach. This approach neglects the large inter-individual variability in perceptual and cognitive abilities that affect aging ADAS users. We investigated the effectiveness of a forward collision warning (FCW) with fixed response parameters in young and older drivers with differing levels of cognitive functioning. Drivers responded to a pedestrian stepping into the driver's path on a simulated urban road. Behavioral metrics included response times (RT) for pedal controls and two indices of risk penetration (e.g., maximum deceleration and minimum time-to-collision (TTC)). Older drivers showed significantly slower responses at several time points compared to younger drivers. The FCW facilitated response times (RTs) for older and younger drivers. However, older drivers still showed smaller safety gains compared to younger drivers at accelerator pedal release and initial brake application when the FCW was active. No significant differences in risk metrics were observed within the condition studied. The results demonstrate older drivers likely differ from younger drivers using a FCW with a fixed parameter set. Finally, we briefly discuss how future research should examine predictive relationships between domains of cognitive functioning and ADAS responses to develop parameter sets to fit the individual.

EFFECTIVENESS OF A HEADS-UP ADAPTIVE LANE DEVIATION WARNING SYSTEM FOR MIDDLE-AGED & OLDER ADULTS.

46 participants (24 younger and 22 older) completed at least one out of four simulated drives designed to test the effectiveness of an Adaptive Lane Deviation Warning (LDW) system, and they drove through both a warnings-on and warnings-off version of each drive. Findings showed that LDW was effective in reducing reaction time for lane deviation corrections for both older (by 1.2 seconds) and younger drivers (by 1.6 seconds). The older and younger drivers did not differ in correction RTs when the warnings were turned off. But older drivers showed slower correction RTs than younger drivers in the warning-on drives. The data indicate that these benefits were specific to LDW rather than general improvement in driving performance. Cognitive processing speed emerged as a particularly robust predictor of benefits from the LDW compared to other domains of cognitive function.

The role of the right superior parietal lobule in processing visual context for the establishment of the egocentric reference frame.

Visual cues contribute to the creation of an observer's egocentric reference frame, within which the locations and orientations of objects can be judged. However, these cues can also be misleading. In the rod-and-frame illusion, for example, a large tilted frame distorts the observer's sense of vertical, causing an enclosed rod to appear tilted in the opposite direction. To determine the brain region responsible for processing these spatial cues, we used TMS to suppress neural activity in the superior parietal lobule of healthy observers. Stimulation of the right hemisphere, but not the left, caused a significant reduction in rod-and-frame susceptibility. In contrast, a tilt illusion caused by a mechanism that does not involve a distortion of the observer's egocentric reference frame was unaffected. These results demonstrate that the right superior parietal lobule is actively involved in processing the contextual cues that contribute to our perception of egocentric space.

Shifts of visuospatial attention do not cause the spatial distortions of the Roelofs effect.

When a visible frame is offset left or right of an observer's objective midline, subjective midline is pulled toward the frame's center, resulting in an illusion of perceived space known as the Roelofs effect. However, a large frame is not necessary to generate the effect-even a small peripheral stimulus is sufficient, raising the possibility that the effect would be brought about by any stimulus that draws attention away from the midline. To assess the relationship between attention and distortions of perceived space, we adopted a paradigm that included a spatial cue that attracted the participant's attention, and an occasional probe whose location was to be reported. If shifts of attention cause the Roelofs effect, the probe's perceived location should vary with the locus of attention. Exogenous attentional cues caused a Roelofs-like effect, but these cues created an asymmetry in the visual display that may have driven the effect directly. In contrast, there was no mislocation after endogenous cues that contained no asymmetry in the visual display. A final experiment used color-contingent attentional cues to eliminate the confound between cue location and asymmetry in the visual display, and provided a clear demonstration that the Roelofs effect is caused by an asymmetric visual display, independent of any shift of attention.

Attentional control settings modulate susceptibility to the induced Roelofs effect.

When a visible frame is offset laterally from an observer's objective midline, the subjective midline is pulled toward the frame's center, causing the frame and any enclosed targets to be misperceived as being shifted somewhat in the opposite direction. This illusion, the Roelofs effect, is driven by environmental (bottom-up) visual cues, but whether it can be modulated by top-down (e.g., task-relevant) information is unknown. Here, we used an attentional manipulation (i.e., the color-contingency effect) to test whether attentional filtering can modulate the magnitude of the illusion. When observers were required to report the location of a colored target, presented within an array of differently colored distractors, there was a greater effect of the illusion when the Roelofs-inducing frame was the same color as the target. These results indicate that feature-based attentional processes can modulate the impact of contextual information on an observer's perception of space.

Visual prior entry for foreground figures.

Attended stimuli reach perceptual-level processes before unattended stimuli do, a finding that is referred to as visual prior entry. We asked whether a similar effect arises for salient objects (foreground figures) in a visual scene. If prior entry holds for figure-ground perception, targets will be perceived to appear earlier on figures than on grounds. Participants performed a temporal order judgment by reporting the order in which targets appeared. Participants perceived that targets appearing on foreground figures occurred earlier than did those appearing on backgrounds. These findings did not result from a response bias for targets appearing on figures. Most important, when figures and grounds were spatially separated and did not share an edge, no prior-entry effects were observed. Our results suggest that figural regions are available to perceptual-level processes sooner than are grounds.