Visual Attentional Demand Research Articles

EHMI on the Vehicle or on the Infrastructure? A Driving Simulator Study

Automated vehicles (AVs) may require the implementation of an external human-machine interface (eHMI) to communicate their intentions to human-driven vehicles. The optimal placement of the eHMI, either on the AV itself or as part of the road infrastructure, remains undetermined. The current driving simulator study investigated the effect of eHMI positioning on human driving behavior, during the approach and execution of right turns at T-intersections. Forty-three participants drove under three conditions: absence of eHMI, eHMI on the AV (eHMIv), and eHMI integrated into the infrastructure (eHMIi). Participants encountered AVs that either yielded or did not yield to their vehicles. The results regarding the placement of the eHMI showed that both concepts are advantageous, but for different reasons. eHMIv was appreciated because implicit and explicit communication are congruent, although the AV must first be visually identified to respond to it. eHMIi was appreciated because a familiar cue is always at a known location in the environment; as a result, participants braked earlier for the intersection and came less close to the AV (which can be interpreted as a safety advantage or efficiency disadvantage). Although there are limitations to a driving simulator study like this, this research provides important insights into the fundamental question of how information placement affects drivers’ visual attention demands and driving behavior, topics that are important in view of the development of future cities.

Auditory change detection and visual selective attention: association between MMN and N2pc.

While the auditory and visual systems each provide distinct information to our brain, they also work together to process and prioritize input to address ever-changing conditions. Previous studies highlighted the trade-off between auditory change detection and visual selective attention; however, the relationship between them is still unclear. Here, we recorded electroencephalography signals from 106 healthy adults in three experiments. Our findings revealed a positive correlation at the population level between the amplitudes of event-related potential indices associated with auditory change detection (mismatch negativity) and visual selective attention (posterior contralateral N2) when elicited in separate tasks. This correlation persisted even when participants performed a visual task while disregarding simultaneous auditory stimuli. Interestingly, as visual attention demand increased, participants whose posterior contralateral N2 amplitude increased the most exhibited the largest reduction in mismatch negativity, suggesting a within-subject trade-off between the two processes. Taken together, our results suggest an intimate relationship and potential shared mechanism between auditory change detection and visual selective attention. We liken this to a total capacity limit that varies between individuals, which could drive correlated individual differences in auditory change detection and visual selective attention, and also within-subject competition between the two, with task-based modulation of visual attention causing within-participant decrease in auditory change detection sensitivity.

Visual feedback and declines in attention are associated with altered visual strategy during a force-steadiness task in older adults.

Greater heterogeneity exists in older adults relative to young adults when performing highly skilled manual tasks. The purpose of this study was to assess the influence of visual feedback and attentional demand on visual strategy during a submaximal force-steadiness task in young and older adults. Eye movements of 21 young (age 20-38 yr; 11 females, 10 males) and 21 older (age 65-90 yr; 11 females, 10 males) adults were recorded during a pinch force-steadiness task while viewing feedback with higher and lower gain and while performing a visuospatial task. For the visuospatial task, participants imagined a star moving around four boxes and reported the final location after a series of directions. Performance on standardized tests of attention was measured. All participants gazed near the target line and made left-to-right saccadic eye movements during the force-steadiness tasks without the visuospatial task. Older adults made fewer saccades than young adults (21.0 ± 2.9 and 23.6 ± 4.4 saccades, respectively) and with higher versus lower gain (20.9 ± 4.0 and 23.7 ± 3.5 saccades, respectively). Most participants used the same visual strategy when performing the visuospatial task though seven older adults used an altered strategy; gaze did not stay near the target line nor travel exclusively left to right. Performance on standardized measures of attention was impaired in this subset compared with older adults who did not use the altered visual strategy. Results indicate that visual feedback influences visual strategy and reveals unique eye movements in some older adults when allocating attention across tasks.NEW & NOTEWORTHY This study contributes novel findings of age-related changes in visual strategy and associations with attentional deficits during hand motor tasks. Older adults used fewer saccades than young adults and with higher versus lower gain visual feedback during a force-steadiness task. A subset of older adults used an altered visual strategy when allocating attention across multiple tasks. Given that this subset demonstrated attentional deficits, the altered visual strategy could serve to indicate motor and/or cognitive impairments.

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.

Neural Correlates of Visual Attention and Short-Term Memory in Children with Reading Difficulty

ABSTRACT Visual attention and memory of 20 children with reading difficulty (Mage = 134 months), 24 chronological (Mage = 138 months) and 19 reading-age controls (Mage = 92 months) were examined using object substitution masking; mask offset delay increases visual attention and visual short-term memory demands. ERP amplitude differences in the N1 (alerting), N2pc (N2-posterior-contralateral; selective attention), and SPCN (sustained posterior contralateral negativity; memory load) were expected between groups. Chronological controls performed best, but ERP results were mixed. No group differences were found for N1 or N2pc. SPCN showed enhanced negativity in reading difficulty, indicating greater memory load and anomalous inhibition.

The association between visual attention and body movement-controlled video games, balance and mobility in older adults

BackgroundBody movement-controlled video games involving physical motion and visual attention may have the potential to train both abilities simultaneously. Our purpose was to determine the associations between performance in these games and visual attention, balance and mobility in a group of older adults. The long-term goal is to identify the optimal type of interactive games with regards to training potential.MethodsFifty healthy adults aged 65+ years participated in this cross-sectional study. Visual attention was measured with static and dynamic versions of a useful field of view (UFV) and a multiple object tracking (MOT) test. Balance was measured with a force plate in bi-pedal quiet stance test (QST) and one-legged stance (OLST). Gait variability and walking speed were assessed with the Five Meter Walk Test (5MWT). Four Microsoft™ Xbox® 360 Kinect™ interactive video games were chosen based on the apparent levels of visual attention demand.ResultsVisual attention (UFV and MOT) was significantly associated with performance in Xbox® Kinect™ games that appeared to have a high visual attention demand (p < 0.05), while there was minimal or no significant association with games with apparent low visual attention demand. Balance and mobility show correlations with visual attention, and with Xbox games.ConclusionThe results suggest that there are relationships between visual attention, balance, mobility and Xbox® Kinect™ game performance. Since different Xbox® games were associated with different balance, mobility and visual attention scores, a variety of such games, rather than a single game, may be most effective for training for falls prevention.

Effects of visual short-term memory load and attentional demand on the contrast response function.

Visual short-term memory (VSTM) load leads to impaired perception during maintenance. Here, we fitted the contrast response function to psychometric orientation discrimination data while also varying attention demand during maintenance to investigate: (1) whether VSTM load effects on perception are mediated by a modulation of the contrast threshold, consistent with contrast gain accounts, or by the function asymptote (1 lapse rate), consistent with response gain accounts; and (2) whether the VSTM load effects on the contrast response function depend on the availability of attentional resources. We manipulated VSTM load via the number of items in the memory set in a color and location VSTM task and assessed the contrast response function for an orientation discrimination task during maintenance. Attention demand was varied through spatial cuing of the orientation stimulus. Higher VSTM load increased the estimated contrast threshold of the contrast response function without affecting the estimated asymptote, but only when the discrimination task demanded attention. When attentional demand was reduced (in the cued conditions), the VSTM load effects on the contrast threshold were eliminated. The results suggest that VSTM load reduces perceptual sensitivity by increasing contrast thresholds, suggestive of a contrast gain modulation mechanism, as long as the perceptual discrimination task demands attention. These findings support recent claims that attentional resources are shared between perception and VSTM maintenance processes.

Microsaccades: Empirical Research and Methodological Advances - Introduction to Part 1 of the Thematic Special Issue.

Microsaccades: Empirical Research and Methodological Advances - Introduction to Part 1 of the Thematic Special Issue.

The Deployment of Young Readers´ Visual Attention across Orthographic Strings: The Influence of Stems and Suffixes

ABSTRACT The goal of the paper was to investigate whether morphological units – stems and suffixes – influence orthographic processing by modulating visual attention demands to the task. Orthographic processing was measured with a visual one-back task requiring letters to be detected within pseudowords not including stems/suffixes, or containing real stems or real suffixes. Fourth grade children (between 9.5 and 10.5 years old) who read in a transparent orthography of a morphologically rich and agglutinative language (Basque) were tested. The results showed that the presence of morphemes in the strings did not improve letter detection performance though it slightly modulated the distribution of visual attention, showing a bias toward the processing of central letters in the presence of a stem. We suggest that the presence of highly regular and recurrent structures prioritizes stem identification, which when achieved, reduces visual attention deployment across the remaining letters.

Concurrent phone texting alters crossing behavior and induces gait imbalance during obstacle crossing

Texting during walking has become a very common daily activity and could alter gait performance, especially during locomotion when additional visual attention is demanded, such as obstacle crossing. The purpose of this study was to examine biomechanical changes in obstructed gait characteristics while engaging in a phone texting activity. Gait analyses were performed on ten young healthy adults under the following two tasks: 1) walking and crossing an obstacle set at a 10% of the subject’s height and 2) walking and crossing an obstacle while responding to a text message. Whole body motion data were collected with a 10-camera motion capture system. Our data demonstrated that a conservative gait pattern was adopted while performing texting when approaching and crossing over the obstacle, which was indicated by slower walking speeds and greater toe-obstacle clearances. This gait pattern was, however, accompanied by a greater body sway in the frontal plane during crossing, which could be an indication of perturbed gait balance control. Increased visual-attentional demand from a concurrent phone texting could negatively impact young pedestrians’ safety during obstacle crossing.

Neural Representation of Working Memory Content Is Modulated by Visual Attentional Demand.

Recent theories assert that visual working memory (WM) relies on the same attentional resources and sensory substrates as visual attention to external stimuli. Behavioral studies have observed competitive tradeoffs between internal (i.e., WM) and external (i.e., visual) attentional demands, and neuroimaging studies have revealed representations of WM content as distributed patterns of activity within the same cortical regions engaged by perception of that content. Although a key function of WM is to protect memoranda from competing input, it remains unknown how neural representations of WM content are impacted by incoming sensory stimuli and concurrent attentional demands. Here, we investigated how neural evidence for WM information is affected when attention is occupied by visual search-at varying levels of difficulty-during the delay interval of a WM match-to-sample task. Behavioral and fMRI analyses suggested that WM maintenance was impacted by the difficulty of a concurrent visual task. Critically, multivariate classification analyses of category-specific ventral visual areas revealed a reduction in decodable WM-related information when attention was diverted to a visual search task, especially when the search was more difficult. This study suggests that the amount of available attention during WM maintenance influences the detection of sensory WM representations.

Attention modulates specific motor cortical circuits recruited by transcranial magnetic stimulation

Skilled performance and acquisition is dependent upon afferent input to motor cortex. The present study used short-latency afferent inhibition (SAI) to probe how manipulation of sensory afference by attention affects different circuits projecting to pyramidal tract neurons in motor cortex. SAI was assessed in the first dorsal interosseous muscle while participants performed a low or high attention-demanding visual detection task. SAI was evoked by preceding a suprathreshold transcranial magnetic stimulus with electrical stimulation of the median nerve at the wrist. To isolate different afferent intracortical circuits in motor cortex SAI was evoked using either posterior–anterior (PA) or anterior–posterior (PA) monophasic current. In an independent sample, somatosensory processing during the same attention-demanding visual detection tasks was assessed using somatosensory-evoked potentials (SEP) elicited by median nerve stimulation. SAI elicited by AP TMS was reduced under high compared to low visual attention demands. SAI elicited by PA TMS was not affected by visual attention demands. SEPs revealed that the high visual attention load reduced the fronto-central P20-N30 but not the contralateral parietal N20-P25 SEP component. P20-N30 reduction confirmed that the visual attention task altered sensory afference. The current results offer further support that PA and AP TMS recruit different neuronal circuits. AP circuits may be one substrate by which cognitive strategies shape sensorimotor processing during skilled movement by altering sensory processing in premotor areas.

Simulator Evaluation of Drivers’ Performance on Rural Highways in relation to Drivers’ Visual Attention Demands

Aim of the study is to investigate, by means of a driving simulator experiment, drivers’ performance in terms of lateral position, speed, deceleration, steering angle, and breaking times on a divided two-lane rural highway in relation to drivers’ visual attention (VD). In the experiment, the virtual scene of twenty different geometric alignment sections without traffic and the VD testing were designed. Twenty-three experienced drivers with the calibration of attention capacity participated in a 30 km drive in an interactive fixed-base simulator. Each participant was required to drive with the controlled speed of 60 km/h along the central lane as repeating random number and was evaluated on VD and driving performances. Three different data analysis techniques were used: (a) statistical tests and hypothesis test of curvature change rate (CCR) of the geometric alignments, visual attention demands, and driving performance data, (b) correlation analysis of VD, CCRs, and driving behaviors, and (c) regression analysis of the VD and CCRs. Results have showed that the driving performance can be effectively influenced by the highway alignment and a prediction model built in this study can evaluate the drivers’ visual attention demands before the highway constructed. The interactions among VD, driving behavior, and CCRs were also found.

Exploring the Impact of Target Eccentricity and Task Difficulty on Covert Visual Spatial Attention and Its Implications for Brain Computer Interfacing

ObjectiveCovert visual spatial attention is a relatively new task used in brain computer interfaces (BCIs) and little is known about the characteristics which may affect performance in BCI tasks. We investigated whether eccentricity and task difficulty affect alpha lateralization and BCI performance.ApproachWe conducted a magnetoencephalography study with 14 participants who performed a covert orientation discrimination task at an easy or difficult stimulus contrast at either a near (3.5°) or far (7°) eccentricity. Task difficulty was manipulated block wise and subjects were aware of the difficulty level of each block.Main ResultsGrand average analyses revealed a significantly larger hemispheric lateralization of posterior alpha power in the difficult condition than in the easy condition, while surprisingly no difference was found for eccentricity. The difference between task difficulty levels was significant in the interval between 1.85 s and 2.25 s after cue onset and originated from a stronger decrease in the contralateral hemisphere. No significant effect of eccentricity was found. Additionally, single-trial classification analysis revealed a higher classification rate in the difficult (65.9%) than in the easy task condition (61.1%). No effect of eccentricity was found in classification rate.SignificanceOur results indicate that manipulating the difficulty of a task gives rise to variations in alpha lateralization and that using a more difficult task improves covert visual spatial attention BCI performance. The variations in the alpha lateralization could be caused by different factors such as an increased mental effort or a higher visual attentional demand. Further research is necessary to discriminate between them. We did not discover any effect of eccentricity in contrast to results of previous research.

Effects of a Virtual Air Speed Error Indicator on Guidance Accuracy and Eye Movement Control during Simulated Flight

We examined whether flight-control performance might be improved by presenting airspeed information to peripheral areas of the visual field using virtual head-up displays (HUDs), and whether participants process these displays using peripheral, rather than central, vision. We found that, compared to a standard HUD speed indicator, a peripherally located virtual speed indicator produced superior altitude control and equivalent or better speed control. Participants' gaze dwell times were more concentrated on flight-path and altitude control information as compared to speed information for the virtual HUD speed indicator. Gaze patterns showed that participants processed the virtual speed indicator with peripheral vision while they needed to directly fixate the traditional military standard HUD speed indicator in central vision. We believe the virtual display allowed participants to acquire speed information in a manner consistent with naturally-evolved orienting processes and therefore reduced central visual field load, attentional demand, and overall mental workload, freeing resources for better flight-path control.

Effects of Visual and Audio Callouts on Pilot Visual Attention during Electronic Moving Map Use

NASA's Taxiway Navigation and Situational Awareness (TNASA)'s in-cockpit Electronic Moving Map (EMM) has been found to improve the efficiency and safety of airport surface (ground taxi) operations. However its design also leads to a paradox: the EMM requires the pilot to look head-down into the cockpit, diverting attention away from the primary, out-the-window (OTW) view. The present study examined the potential benefits of pilots attending to the EMM only when directed by either audio or visual “head-up” callouts. The callouts were presented in either a general (“check map”) or specific (“traffic conflict your right”) form. The visual attention effects of audio and visual callouts, in both general and specific form, were assessed using an eye tracking system in the context of a medium fidelity part-task ground taxi simulation. Our objective was to determine ways to maximize the utility of the EMM while minimizing its head-down visual attention demands. Preliminary results showed all callout types, specifically audio, increased OTW dwell time, with a stated preference for having any callout present over not having one.

Visual Cues and Attention Demand in Locomotor Positioning

The aim of this study was to determine what visual cues are used to assess the time-to-contact (Tc) with a stationary target during locomotor positioning. For this purpose, we performed an experiment with restricted central visual cues and analysed the attention demand involved in use of visual cues. 11 subjects were asked to walk towards a target surface and stop in front of it. Two target sizes were used: the tau strategy, consisting of assessing Tc from the relative expansion rate of the target during locomotion, was possible only with the larger one. The same task was also performed in a dual-task situation wherein reaction time to auditory stimuli was recorded. Analysis showed that braking was initiated earlier only in the dual-task situation involving the small target. The secondary task reaction time also increased considerably and actually even sooner when the positioning was done on the small target. These results suggest that a strategy other than tau may be used to assess Tc: with this strategy, the braking distance and walking speed are taken into account. Furthermore, different processing levels must have been involved in these two different methods, since the attention demand differed from one positioning task to the other.

Validation of a Driving Simulation Facility for Instrument Panel Task Performance

The purpose of this study was to compare driver performance of 17 conventional automotive instrument panel (IP) tasks on the road and in the driving simulator and to validate use of the simulator in evaluation of an IP design. Introduction of random crosswind was shown to influence the driving workload in the simulator. Comparisons of the visual attentional and manual demand measures demonstrated that a driving environment close to that in the car is provided by the simulator at zero crosswind level and that the driving simulator can be used to evaluate automotive IP designs.

Visual attentional demand of an in-car navigation display system : Wierwille, W.W., Antin, J.F., Dingus, T.A., and Hulse, M.C. In: Vision in Vehicles — II, A.G. Gale, M.H. Freeman, C.M. Haslegrave, P. Smith and S.P. Taylor (Eds). North-Holland, Amsterdam, 1988, pp 307–316, 0 refs.

Two research studies were performed in which an operational in-car navigation display system was tested and evaluated. In the first study, the visual attentional demand requirements for specific tasks associated with the navigation system were compared with those of a wide variety of conventional (though modern) instrument panel tasks. The purpose in gathering these data was to evaluate whether or not the navigation tasks created demands that were greater than those of conventional tasks, and if so, by how much. The second study addressed the effectiveness, efficiency, and strategy associated with three different kinds of route guidance, memorized route, conventional paper map, and the navigation system. Results of the studies indicate that drivers are able to use the navigation system effectively and that it compares favorably with paper maps. However, visual scan patterns are changed when using the navigation system. Furthermore, drivers use a visual sample process which is quite different from that used for either paper maps or memorized route. Other findings indicate that the visual attentional demand of most navigator tasks is within the range of that for conventional tasks, however, a few tasks do have high visual attentional demand. These latter tasks could be modified to reduce their visual attentional demand.

Attentional demand requirements of an automobile moving-map navigation system

The objective of this research was to assess the driver visual attentional demand requirements of an operational in-car navigation system. Thirty-two driver subjects ranging in age from 18 to 73 drove a specially instrumented vehicle on various types of public roadways with varying traffic conditions. Drivers performed both specific navigation system tasks and conventional tasks using dashboard instrumentation. Comparisons were then made between the two types of tasks. Results show that the demand of most of the navigation tasks was comparable to that of one or more conventional tasks. Modifying the remaining navigation tasks to make information more readily available would reduce their demand.