High Visual Load Research Articles

ОЦІНКА СВІТЛОВОГО СЕРЕДОВИЩА З УРАХУВАННЯМ БЕЗПЕКИ ПРАЦІ ТА ПРАЦЕЗДАТНОСТІ ЛЮДЕЙ ПРИ ВИКОНАННІ РОБІТ ВИСОКОЇ ЗОРОВОЇ СКЛАДНОСТІ

Purpose. Development of a complex methodology for evaluating the production light environment when performing works of high visual complexity. Methodology is to use comparative analysis of methodical approaches to the assessment of the light environment, which is the basis for the standardization of the light environment of workplaces in the EU countries and Ukraine. The regulatory documents have been analyzed from the point of view of the impact of the light environment on work safety, work capacity, and the psychophysiological state of workers who perform visual work of high complexity, as the most vulnerable category of workers. Results. Our analysis of international and Ukrainian acts that regulate the quality of the light environment at workplaces and research methods that take into account the quality of the light environment when performing work of high visual complexity allows us to establish that they do not fully take into account the requirements for the light environment in the work area and on workplaces.Taking into account the data of the world experience when assessing working conditions by the light environment factor, the justification and selection of the light environment criteria has been carried out for the first time, which allows to qualitatively assess the influence of the light environment when performing works of high visual complexity. For the first time, an algorithm for step-by-step assessment of the quality of lighting in the workplace is proposed to assess the components of the light environment, taking into account the impact of natural and artificial lighting on work capacity, safety, and psychophysiological activity, taking into account the psychophysiological state of workers. Scientific novelty. For the first time, a scientific and practical justification and selection of criteria for the parameters of the light environment has been carried out, which allows to qualitatively assess the influence of the light environment during the performance of visual tasks of high complexity. Practical significanse. The results of the implementation of the research make it possible to improve the methods of researching the production environment. Taking into account the factor of the light environment allows to increase the safety of work of a wide category of workers in various industries, which is especially important in connection with the spread of automation of production in Ukraine and the world, and, accordingly, an increase in the category of workers performing work related to high visual load. Keywords: visual environment; lighting environment; glance; labor protection.

Research on drivers’ eye movement characteristics in the combined section of longitudinal slope and curve in the extra-long underwater tunnel

To explore the effects of a longitudinal slope, a curve, and their combined action on the eye movement characteristics and driving safety of drivers in extra-long underwater tunnel, vehicle tests are conducted. Their purpose is to obtain data on the pupil area change rate, blink duration, fixation duration, and average saccade time when a driver passes through each longitudinal slope and curve combination section. The change laws of‘ the eye movement characteristics in different curves and longitudinal slopes are analyzed. Moreover, the change models of the pupil area change rate, blink duration, fixation duration, and average saccade time of drivers under the combined action of a longitudinal slope and a curve are established. Considering multiple eye movement characteristics comprehensively, the TOPSIS method is used to analyze the drivers’ visual load of different longitudinal slope and curve combination sections. The results show that the interaction between a longitudinal slope and a curve has a significant impact on the eye movement characteristics of the drivers, with their combined effect being greater than that of a single factor, i.e., longitudinal slope or curve. A large longitudinal slope and a small curve radius imply a high pupil area change rate, long fixation duration, short blink duration, short average saccade time, and high visual load.

ОБГРУНТУВАННЯ АКТУАЛЬНОСТІ РОЗРОБКИ СУЧАСНИХ МЕТОДИК ДОСЛІДЖЕННЯ ВИРОБНИЧОГО СЕРЕДОВИЩА З УРАХУВАННЯМ СВІТЛОВОГО ФАКТОРУ

Purpose. Justification of the relevance of development of modern methods of researching the production environment with light factor taking into account. Methodology. Categories of workers in different industries have been considered and related loads on the visual analyzer have been identified. The comparative analysis of the current requirements of the EU and Ukraine for standardizing the light environment at the workplaces of workers performing highly complex visual work has been carried out. Results. The research shows the prevalence of visual works in construction industry and in other industries in Ukraine and in the world. The greatest risk group for the development of occupational diseases as a result of the negative impact of the light environment are workers who perform highly complex visual work. The study of data from world experience, which testify to the importance of the light environment for the formation of optimal working and learning conditions, the prevention of injuries and the occurrence of acquired diseases, leads us to conclusion, that we require the deepen scientific research on the complex influence of all factors of the light environment on the physio-psychological state of workers. That may help us to establish mathematical models of the risk to the health of workers under the conditions of rational use of natural lighting in workplaces and the design of artificial lighting for workers in the category of "engineers and designers" who perform visual work of high complexity, including the use of innovative engineering and technical solutions. Scientific novelty. The category of "engineers and designers" has been defined as a separate group of workers. Our research and analysis of documents regulating the quality of the light environment in premises where visual work of high complexity is carried out, has shown that the current regulatory documents do not fully take into account all the potential dangers of the light environment on workers. This affects the certification of workplaces, the quality of their design and the completeness of the fulfillment of safety requirements regarding the light environment and justifies the relevance of developing new methods of researching the production environment taking into account the light factor. Practical significanse. Improving the methods of researching the production environment taking into account the light factor can allow to increase the safety of work of a wide category of workers in various industries, which is especially important in connection with the spread of automation of production in Ukraine and in the world, and, accordingly, the increase in the category of workers performing work associated with high visual load per person.

Effects of unintentional coordination on attentional load.

The goal of this study was to evaluate the impact of unintentional (spontaneous) coordination on high attentional visual load. More precisely, we wondered whether such coordination could free up some attentional resources and help improve performance in other more demanding attentional tasks. An experiment was performed in which participant attentional allocation was challenged by performing three tasks simultaneously while simultaneously being induced to unintentional entrain to an environmental rhythm. The first task was an interception task associated with a Stroop test to increase their attentional load. The second task was a reaction time test to alarms in different modalities (auditory, visual and bimodal) which was used to assess participant attentional load. The third task was a motor task in which participants were asked to swing their legs at a preferred frequency. The interface background brightness intensity was either synchronized in real time using a bidirectional coupling to participant leg movement or the background brightness was not changing at all. Our results on the reaction time task demonstrated that participants exhibited better reaction times for alarms in the bimodal condition than in the auditory condition and lastly for the visual condition. Also, participants exhibited a lower reaction time to alarms when the background brightness was synchronizing with their leg regardless the alarm modality. Overall, our study suggests a beneficial effect of unintentional environmental coordination on attentional resource allocation and highlights the importance of bidirectionality in interaction.

Systematic Review of the Development of Spatial Intelligence through Augmented Reality in STEM Knowledge Areas

This study presents a systematic review (SR) of the literature on the use of Augmented Reality (AR) for the development of spatial skills of secondary and higher education students in the teaching of subjects related to the area of Science, Technology, Engineering and Mathematics (STEM). Numerous researchers have confirmed that students tend to have difficulties in acquiring learning content with a high visual load, which is why AR is being used to improve teaching–learning processes. This paper aims to present information of interest to researchers, teachers and software developers about the advantages and limitations of AR in the development of spatial intelligence, the integration and development of AR applications, as well as the predominant spatial skills and assessment methods. In this regard, an initial search was carried out which returned 242 articles. After reviewing and assessing their eligibility, a total of 17 papers published since 2002 were selected. The findings reveal an increase in the number of investigations over the last few years. Some of the most notable findings are the improvement of spatial skills of students through the inclusion of AR in educational environments, the need for teacher training, the lack of personalization in the applications developed and the scarcity of augmented materials in the form of Open Educational Resources (OER).

Which signal modalities do cyclists prefer based on experiences in road traffic?

Objective: On-bike systems warning cyclists about critical situations are a promising approach to improve safety. The chosen warning modality might strongly influence whether the cyclist accepts the system. So far, cyclists’ warning preferences have not been analyzed based on field data. They were only analyzed through web-based surveys or a simulator study without including the three most promising signal types (i.e., visual, auditory and vibro-tactile). This study aims to evaluate the signal preferences for transmitting information to cyclists based on experience of the signals in the field. Method: We conducted a field study where participants received signals of different signal types, i. e. visual, auditory and vibro-tactile signals, while cycling. After completing the course, all participants answered a questionnaire on their subjective experiences of the signals. The participants separately cycled a 10 km long route in road traffic. All participants received 12 signals per modality on predefined GPS coordinates. The course covered different environmental conditions like loud ambient noise, gravel roads or high visual load. Results: The data of 55 participants was analyzed. The participants chose the auditory and vibro-tactile signal over the visual signal. When asked, they significantly preferred an auditory warning to the other two signal types. The participants rated the auditory signal as most urgent and frequently associated it with warnings. Participants reported the visual signal as distracting from the cycling task and the vibro-tactile signals as difficult to distinguish from surface related vibrations. Conclusion: The advantages of different signal modalities can be applied to develop information transmission systems in the cycling context. Our results show that the signal types have inherent qualities which may fit into different areas of application. This study highlights that the choice of a warning modality needs to be balanced on a combination of noticeability, criticality and personal preference.

Factors associated with dynamic balance in people with Persistent Postural Perceptual Dizziness (PPPD): a cross-sectional study using a virtual-reality Four Square Step Test

BackgroundPersistent postural-perceptual dizziness (PPPD) is a condition characterized by chronic subjective dizziness and exacerbated by visual stimuli or upright movement. Typical balance tests do not replicate the environments known to increase symptoms in people with PPPD—crowded places with moving objects. Using a virtual reality system, we quantified dynamic balance in people with PPPD and healthy controls in diverse visual conditions.MethodsTwenty-two individuals with PPPD and 29 controls performed a square-shaped fast walking task (Four-Square Step Test Virtual Reality—FSST-VR) using a head-mounted-display (HTC Vive) under 3 visual conditions (empty train platform; people moving; people and trains moving). Head kinematics was used to measure task duration, movement smoothness and anterior–posterior (AP) and medio-lateral (ML) ranges of movement (ROM). Heart rate (HR) was monitored using a chest-band. Participants also completed a functional mobility test (Timed-Up-and-Go; TUG) and questionnaires measuring anxiety (State-Trait Anxiety Inventory; STAI), balance confidence (Activities-Specific Balance Confidence; ABC), perceived disability (Dizziness Handicap Inventory) and simulator sickness (Simulator Sickness Questionnaire). Main effects of visual load and group and associations between performance, functional and self-reported outcomes were examined.ResultsState anxiety and simulator sickness did not increase following testing. AP-ROM and HR increased with high visual load in both groups (p < 0.05). There were no significant between-group differences in head kinematics. In the high visual load conditions, high trait anxiety and longer TUG duration were moderately associated with reduced AP and ML-ROM in the PPPD group and low ABC and high perceived disability were associated with reduced AP-ROM (|r| = 0.47 to 0.53; p < 0.05). In contrast, in controls high STAI-trait, low ABC and longer TUG duration were associated with increased AP-ROM (|r| = 0.38 to 0.46; p < 0.05) and longer TUG duration was associated with increased ML-ROM (r = 0.53, p < 0.01).ConclusionsFSST-VR may shed light on movement strategies in PPPD beyond task duration. While no main effect of group was observed, the distinct associations with self-reported and functional outcomes, identified using spatial head kinematics, suggest that some people with PPPD reduce head degrees of freedom when performing a dynamic balance task. This supports a potential link between spatial perception and PPPD symptomatology.

Visual load effects on the auditory steady-state responses to 20-, 40-, and 80-Hz amplitude-modulated tones

Ignoring background sounds while focusing on a visual task is a necessary ability in everyday life. If attentional resources are shared between modalities, processing of task-irrelevant auditory information should become attenuated when attentional capacity is expended by visual demands. According to the early-filter model, top-down attenuation of auditory responses is possible at various stages of the auditory pathway through multiple recurrent loops. Furthermore, the adaptive filtering model of selective attention suggests that filtering occurs early when concurrent visual tasks are demanding (e.g., high load) and late when tasks are easy (e.g., low load). To test these models, this study examined the effects of three levels of visual load on auditory steady-state responses (ASSRs) at three modulation frequencies. Subjects performed a visual task with no, low, and high visual load while ignoring task-irrelevant sounds. The auditory stimuli were 500-Hz tones amplitude-modulated at 20, 40, or 80 Hz to target different processing stages of the auditory pathway. Results from bayesian analyses suggest that ASSRs are unaffected by visual load. These findings imply that attentional resources are modality specific and that the attentional filter of auditory processing does not vary with visual task demands.

Pedestrian distraction: The effects of road environment complexity and age on pedestrian’s visual attention and crossing behavior

Introduction: Little is known about how characteristics of the environment affect pedestrians’ road crossing behavior. Method: In this work, the effect of typical urban visual clutter created by objects and elements in the road proximity (e.g., billboards) on adults and children (aged 9–13) road crossing behavior was examined in a controlled laboratory environment, utilizing virtual reality scenarios projected on a large dome screen. Results: Divided into three levels of visual load, results showed that high visual load affected children’s and adults’ road crossing behavior and visual attention. The main effect on participants’ crossing decisions was seen in missed crossing opportunities. Children and adults missed more opportunities to cross the road when exposed to more cluttered road environments. An interaction with age was found in the dispersion of the visual attention measure. Children, 9–10 and 11–13 years old, had a wider spread of gazes across the scene when the environment was highly loaded—an effect not seen with adults. However, unexpectedly, no other indication of the deterring effect was found in the current study. Still, according to the results, it is reasonable to assume that busier road environments can be more hazardous to adult and child pedestrians. Practical Applications: In that context, it is important to further investigate the possible distracting effect of causal objects in the road environment on pedestrians, and especially children. This knowledge can help to create better safety guideline for children and assist urban planners in creating safer urban environments.

Auditory Figure-Ground Segregation Is Impaired by High Visual Load.

Figure-ground segregation is fundamental to listening in complex acoustic environments. An ongoing debate pertains to whether segregation requires attention or is “automatic” and preattentive. In this magnetoencephalography study, we tested a prediction derived from load theory of attention (e.g., Lavie, 1995) that segregation requires attention but can benefit from the automatic allocation of any “leftover” capacity under low load. Complex auditory scenes were modeled with stochastic figure-ground stimuli (Teki et al., 2013), which occasionally contained repeated frequency component “figures.” Naive human participants (both sexes) passively listened to these signals while performing a visual attention task of either low or high load. While clear figure-related neural responses were observed under conditions of low load, high visual load substantially reduced the neural response to the figure in auditory cortex (planum temporale, Heschl's gyrus). We conclude that fundamental figure-ground segregation in hearing is not automatic but draws on resources that are shared across vision and audition.SIGNIFICANCE STATEMENT This work resolves a long-standing question of whether figure-ground segregation, a fundamental process of auditory scene analysis, requires attention or is underpinned by automatic, encapsulated computations. Task-irrelevant sounds were presented during performance of a visual search task. We revealed a clear magnetoencephalography neural signature of figure-ground segregation in conditions of low visual load, which was substantially reduced in conditions of high visual load. This demonstrates that, although attention does not need to be actively allocated to sound for auditory segregation to occur, segregation depends on shared computational resources across vision and hearing. The findings further highlight that visual load can impair the computational capacity of the auditory system, even when it does not simply dampen auditory responses as a whole.

Taking Attention Away from the Auditory Modality: Context-dependent Effects on Early Sensory Encoding of Speech

Increasing visual perceptual load can reduce pre-attentive auditory cortical activity to sounds, a reflection of the limited and shared attentional resources for sensory processing across modalities. Here, we demonstrate that modulating visual perceptual load can impact the early sensory encoding of speech sounds, and that the impact of visual load is highly dependent on the predictability of the incoming speech stream. Participants (n = 20, 9 females) performed a visual search task of high (target similar to distractors) and low (target dissimilar to distractors) perceptual load, while early auditory electrophysiological responses were recorded to native speech sounds. Speech sounds were presented either in a ‘repetitive context’, or a less predictable ‘variable context’. Independent of auditory stimulus context, pre-attentive auditory cortical activity was reduced during high visual load, relative to low visual load. We applied a data-driven machine learning approach to decode speech sounds from the early auditory electrophysiological responses. Decoding performance was found to be poorer under conditions of high (relative to low) visual load, when the incoming acoustic stream was predictable. When the auditory stimulus context was less predictable, decoding performance was substantially greater for the high (relative to low) visual load conditions. Our results provide support for shared attentional resources between visual and auditory modalities that substantially influence the early sensory encoding of speech signals in a context-dependent manner.

Multiactuator Haptic Feedback on the Wrist for Needle Steering Guidance in Brachytherapy

Brachytherapy is a cancer treatment procedure where long needles are inserted toward an inner body target in order to deliver radioactive seeds that treat the cancer cells. Controlling the trajectory of the needle is very challenging as it deviates from a straight path during insertion. In this letter, we present the pilot study of usefulness of a wristband with haptic feedback designed to help surgeons guide the needle toward a desired destination. The wristband embeds eight miniature actuators distributed around the wrist. The actuators are controlled to generate different haptic stimuli, each of which informs the user about a necessary needle steering manoeuvre. We describe the design of the wristband and its evaluation in two distinct user studies. In the first study, we evaluate how accurately users can identify the vibration patterns. In the second study, we focus on how the user responds to these patterns while performing needle insertion into tissue in an environment with high cognitive visual load. The reported average success rate in identifying the haptic pattern and the success rate in performing the correct action during needle insertion are 86% and 72%, respectively. These results suggest that the device could work in tandem with a needle steering algorithm to help surgeons achieve high quality implants and develop needle steering skills.

Inattentional Deafness: Visual Load Leads to Time-Specific Suppression of Auditory Evoked Responses.

The present work clarifies the neural underpinning of inattentional deafness under high visual load. The findings of near-simultaneous load effects on both visual and auditory evoked responses suggest shared audiovisual processing capacity. Temporary depletion of shared capacity in perceptually demanding visual tasks leads to a momentary reduction in sensory processing of auditory stimuli, resulting in inattentional deafness. The dynamic "push-pull" pattern of load effects on visual and auditory processing furthers our understanding of both the neural mechanisms of attention and of cross-modal effects across visual and auditory processing. These results also offer an explanation for many previous failures to find cross-modal effects in experiments where the visual load effects may not have coincided directly with auditory sensory processing.

Multi-modal distraction: Insights from children’s limited attention

How does the multi-sensory nature of stimuli influence information processing? Cognitive systems with limited selective attention can elucidate these processes. Six-year-olds, 11-year-olds and 20-year-olds engaged in a visual search task that required them to detect a pre-defined coloured shape under conditions of low or high visual perceptual load. On each trial, a peripheral distractor that could be either compatible or incompatible with the current target colour was presented either visually, auditorily or audiovisually. Unlike unimodal distractors, audiovisual distractors elicited reliable compatibility effects across the two levels of load in adults and in the older children, but high visual load significantly reduced distraction for all children, especially the youngest participants. This study provides the first demonstration that multi-sensory distraction has powerful effects on selective attention: Adults and older children alike allocate attention to potentially relevant information across multiple senses. However, poorer attentional resources can, paradoxically, shield the youngest children from the deleterious effects of multi-sensory distraction. Furthermore, we highlight how developmental research can enrich the understanding of distinct mechanisms controlling adult selective attention in multi-sensory environments.

Optimization of the uveoscleral outflow in the patients with primary open-angle glaucoma and resistant to latanoprost intraocular pressure

The aim of our study was to investigate the role of visual load levels in intraocular pressure (IOP) elevation in patients taking prostaglandin analogs and to try to optimize the conditions for their effects on the uveoscleral outflow. A total of 33 patients (40 eyes) with first diagnosed primary open-angle glaucoma (POAG) and resistance to latanoprost 0.005 % IOP were included in this study. These patients were pre-examined with the definition of visual and reading acuity, refraction, and true, tolerant, and target IOP with perimetry and ophthalmoscopy. Subjects were divided into two groups of comparable age, sex, and refraction. In each group, the thickness of the ciliary body by ultrasound biomicroscopy was investigated, and the level of near visual load and tolerated correction for near were defined. It was found that in both groups, 85 % of the eyes with POAG had moderately high (3–6 h per day) and high (> 6 h per day) near visual load. Maximal ciliary body thickness in both groups was significantly higher than the results received by other authors: 0.881 ± 0.039 mm in group 1 and 0.889 ± 0.049 mm in group 2. Also, a direct dependence of the ciliary body thickness on the true value of IOP (r = 0.52) was observed. Hypercorrection of presbyopia was made in group 1 gradually, in steps of 0.25 D. The value of additional correction averaged 0.5 ± 0.13 D. The magnitude of additional correction was inversely related to age (r = 0.79). To assess the effectiveness of presbyopia overcorrection in reducing IOP 1 year later, tonometry, visual acuity check, perimetry (MD/year method), ophthalmoscopy, and measurement of the thickness of the ciliary body were performed. In group 1, the reduction of IOP (17.3 ± 0.84 mmHg) was statistically significant (p < 0.01), and its value was close to the average tolerant IOP (17.0 ± 0.67 mmHg), but was higher than the target (14.3 ± 0.67 mmHg). Also, in this group, statistically significant (p < 0.01) decrease in the thickness of the ciliary body was observed, more marked in patients with high near visual load (r = 0.47). Progression of glaucoma according to perimetry was significantly less (p < 0.01) in the group with hypercorrection of presbyopia as compared with the group with ordinary correction. Overcorrection of presbyopia, in addition to antihypertensive therapy, may be a way to regulate IOP for patients with high near visual load and POAG.

Right or Left: Tactile Display for Route Guidance of Drivers

Abstract A tactile interface is an alternative channel of communication, which can be utilized to display navigational instructions in cars under high visual and auditory load conditions. We investigated the use of a tactile belt for turn-by-turn information presentation in cars, which was originally designed for the route guidance of blind and pedestrian users. Important information artifacts in turn-by-turn route guidance are the distance to an upcoming crossing and the direction to follow. The tactile belt was examined in a pilot study for presenting direction information in a car navigation system. The pilot study was used to explore first ideas of tactile encodings for direction presentation with the tactile belt. The study presented in this article compares these designs systematically for their use in tactile route guidance in the car. For this purpose we conducted an experiment with 10 participants on real urban roads to evaluate three different vibrotactile patterns. The results show that the “two vibrators front design” was significantly different than the “two vibrators side design”. The two vibrator front encoding was preferred significantly. The performance of the participants on two vibrators front design was significantly different than the two vibrators side design. The Friedman test showed a significant difference in the usability of all three vibrotactile patterns. A significant difference was found in the ease of use of two vibrators front encoding compared to other encodings. On the basis of quantitative and qualitative results, we conclude that the two vibrators front encoding is comparatively is the better design for presenting the direction information. Our findings will be helpful for the car industry in designing the tactile based car navigation systems.

Processing of angry voices is modulated by visual load

Visual perceptual load has been shown to modulate brain activation to emotional facial expressions. However, it is unknown whether cross-modal effects of visual perceptual load on brain activation to threat-related auditory stimuli also exist. The current fMRI study investigated brain responses to angry and neutral voices while subjects had to solve an easy or a demanding visual task. Although the easy visual condition was associated with increased activation in the right superior temporal region to angry vs. neutral prosody, this effect was absent during the demanding task. Thus, our results show that cross-modal perceptual load modulates the activation to emotional voices in the auditory cortex and that high visual load prevents the increased processing of emotional prosody.

Effects of increasing visual load on aurally and visually guided target acquisition in a virtual environment

The aim of the present study is to investigate interactions between vision and audition during a target acquisition task performed in a virtual environment. We measured the time taken to locate a visual target (acquisition time) signalled by auditory and/or visual cues in conditions of variable visual load. Visual load was increased by introducing a secondary visual task. The auditory cue was constructed using virtual three-dimensional (3D) sound techniques. The visual cue was constructed in the form of a 3D updating arrow. The results suggested that both auditory and visual cues reduced acquisition time as compared to an uncued condition. Whereas the visual cue elicited faster acquisition time than the auditory cue, the combination of the two cues produced the fastest acquisition time. The introduction of secondary visual task differentially affected acquisition time depending on cue modality. In conditions of high visual load, acquiring a target signalled by the auditory cue led to slower and more error-prone performance than acquiring a target signalled by either the visual cue alone or by both the visual and auditory cues.

The inability to ignore auditory distractors as a function of visual task perceptual load.

Using a response competition paradigm, we investigated the ability to ignore target response-compatible, target response-incompatible, and neutral visual and auditory distractors presented during a visual search task. The perceptual load model of attention (e.g., Lavie & Tsal, 1994) states that task-relevant processing load determines irrelevant distractor processing in such a way that increasing processing load prevents distractor processing. In three experiments, participants searched sets of one (easy search) or six (hard search) similar items. In Experiment 1, visual distractors influenced reaction time (RT) and accuracy only for easy searches, following the perceptual load model. Surprisingly, auditory distractors yielded larger distractor compatibility effects (median RT for incompatible trials minus median RT for compatible trials) for hard searches than for easy searches. In Experiments 2 and 3, during hard searches, consistent RT benefits with response-compatible and RT costs with response-incompatible auditory distractors occurred only for hard searches. We suggest that auditory distractors are processed regardless of visual perceptual load but that the ability to inhibit cross-modal influence from auditory distractors is reduced under high visual load.

Vertical Auditory Localization for Spatial Orientation

The use of three-dimensional auditory technology which provides localization of auditory cues presented through headphones is proposed as a means of providing supplemental information to pilots on the spatial orientation of an aircraft. This technique shows promise for reducing accidents due to spatial disorientation associated with high visual load. A study was conducted using Air Force pilots as subjects to determine desirable cue characteristics for accurately localizing auditory cues using this technique. The study examined the use of nine different cue types at each of two frequency levels. It was found that the accuracy of subjects' localization of cues in elevation was greatly enhanced by the use of multidimensional cues which provided redundant elevation information through varying frequencies and distance from the horizon cues in addition to the inherent spatial location information.