Visual illusions in pilots

BACKGROUND: Increased gravito-inertial acceleration, or hypergravity, such as produced in a centrifuge or in an aircraft coordinated turn, causes humans to systematically overestimate their roll tilt in the dark. This is known as the "G-excess" illusion. We have previously modified a mathematical observer model of dynamic orientation perception to replicate these illusory tilt perceptions. This modified model also made a novel, previously untested, prediction that humans would underestimate acute roll tilt in reduced gravitational environments (hypogravity)...

Faces are one of the most socially significant visual stimuli encountered in the environment, whereas pareidolias are illusions of faces arising from ambiguous stimuli in the environment. Autism spectrum disorder (ASD) is characterised by deficits in response to social stimuli. We found that children with ASD (n = 60) identify significantly fewer pareidolic faces in a sequence of ambiguous stimuli than typically developing peers. The two groups did not differ in the number of objects identified, indicating that the children with ASD had a specific lack of attention to faces...

OBJECTIVE: To determine the location of cortical activation during a visual illusion walking paradigm, a recently proposed treatment for spinal cord injury (SCI)-related neuropathic pain, in persons with SCI compared with able-bodied controls. DESIGN: Pilot experimental functional magnetic resonance imaging (fMRI) trial. SETTING: Outpatient rehabilitation clinic. PARTICIPANTS: Persons with paraplegia (n=3) and able-bodied participants (n=5) were included in this study...

Spatial orientation of pilots using a cockpit exterior surveillance system was tested in real nighttime helicopter flights. Major factors complicating adequate spatial orientation and provoking visual illusions in pilots are lack of information for spatial depth (relation) perception in two-dimensional TV images altering their position along the horizontal and vertical lines of trajectory and simultaneous piloting and target search-identification operations. Reliability of pilot's spatial orientation could be improved by displaying on the exterior imaging screen also relevant flight navigation parameters...

Despite aggressive efforts in spatial disorientation (SD) research, hardware development, and training, the operational impact of SD in terms of crew and aircraft losses remains significant. Current training in spatial orientation is primarily composed of didactic lectures on the anatomy and physiology of the sensory systems. Significant efforts have been concentrated on reproducing various types of visual and vestibular "illusions" that pilots might encounter in flight, with limited and varying success. Unfortunately, the terms of "SD" and "illusion" have been used synonymously, leading to the general belief that if one were to be exposed to a specific type of illusion, one can prevent or avoid SD mishaps...

BACKGROUND: Apomorphine infusion therapy remains under-used and there are no comparative studies of motor and non-motor effects of apomorphine infusion. METHODS: In this paper we report preliminary results from an ongoing clinical observational "real life" surveillance-based study focused on effects of this therapy on non-motor symptoms and health-related quality of life in a group of patients on apomorphine. RESULTS: Apomorphine infusion led to highly significant improvements in UPDRS 3 (p = 0...

On the ground, the essential requirement to remain orientated is a largely unconscious activity. In flight, orientation requires a conscious effort by the pilot particularly when the visual environment becomes degraded and a deceptive force environment becomes the frame of reference. Furthermore, an unusual force environment can determine the apparent location of objects within a limited visual scene, sometimes with disastrous consequences. This review outlines the sources of pilot disorientation that arise from the visual and force environment of flight and their interaction...

The binocular depth inversion test (BDIT) measures a common illusion of visual perception whereby implausible objects are seen as normal, e.g., a hollow face is perceived as a normal, convex face. Such inversion is frequent, especially for objects with a high degree of familiarity. Under normal conditions, cognitive factors apparently override the binocular disparity cues of stereopsis. This internal mechanism of "censorship" of perception, which balances "top-down" and "bottom-up" processes of perception to come to a cognitive coherence, which is congruent to previous experience and concepts, appears to be disturbed in (pro-)psychotic states...

Results of psychological "additional investigation" of the crash of Boeing-737, "Aeroflot-Nord" on 14.09.2008 near Perm are presented. 37 pilots from the one of the leading airline companies sensed the attitude and rolling out the aircraft to the forward flight under the moving horizon with straight display of bank and tangage (view from the aircraft to the ground) in model conditions. 29 pilots (78.4%) made a mistake at determining the roll direction and tangage, they made a mistake at determining the roll direction 61 times (16...

We explored whether color afterimages and faint physical chromatic stimuli are processed equivalently by the visual system. Afterimage visibility in classic illusions appears to be particularly influenced by consistent contexts, while real stimulus versions of these illusions are absent in the literature. Using both a matching and a nulling paradigm, we present converging evidence that luminance edges enhance the perceived saturation of afterimages more than they do physical stimuli of similar appearance. We suggest that afterimages violate the response norms associated with real stimuli...

A theme in sensory perception is that exposure to a stimulus causes perception of subsequent stimuli to be shifted in the opposite direction. Such phenomenon is known as aftereffect and has been extensively described in the visual system as well as recently described for the vestibular system during translation. It is known from aviation studies that after a maneuver in roll, pilots can experience a false perception of roll in the opposite direction. The magnitude and duration of this effect as well as the potential influence of the gravity vector have not previously been defined...

INTRODUCTION: Spatial disorientation (SD) is still a contributing factor in many aviation accidents, stressing the need for adequate SD training scenarios. In this article we focused on the post-roll effect (the sensation of rolling back after a roll maneuver, such as an entry of a coordinated turn) and investigated the effect of roll stimuli on the pilot's ability to stabilize their roll attitude. This resulted in a ground-based demonstration scenario for pilots. METHODS: The experiments took place in the advanced 6-DOF Desdemona motion simulator, with the subject in a supine position...

This work describes the solvent-induced hallucinatory experiences of 10 male and seven female teenagers in Mexico City from 1998 to 2000. The youth were recruited from public schools through a combined snowball and convenience sampling procedure. Inclusion criteria were: 13-18 years of age, school attendance, living with family, and weekly toluene-based solvent misuse. Interested students were interviewed and transcripts were analyzed. Hallucinations and illusions were common, including changes in color perception, visual, somatic, auditory, and tactile hallucinations...

Mirror therapy, which provides the visual illusion of a functional paretic limb by using the mirror reflection of the non-paretic arm, is used in the rehabilitation of hemiparesis after stroke in adults. We tested the effectiveness and feasibility of mirror therapy in children with hemiplegia by performing a pilot crossover study in ten participants (aged 6-14 y; five males, five females; Manual Ability Classification System levels: one at level I, two at level II, four at level III, three at level IV) randomly assigned to 15 minutes of daily bimanual training with and without a mirror for 3 weeks...

BACKGROUND: The McConnell sign has been regarded as a highly specific echo finding in acute pulmonary embolism (aPE). However, a completely satisfying explanation to account for this observation in aPE remains elusive. We used longitudinal velocity vector imaging (VVI) using a dedicated software program (Research Arena, Siemens, California) to assess regional right ventricular global and apical (RVa) mechanics between aPE and chronic pulmonary hypertension (cPH) patients. METHODS: Standard echo parameters of RV performance as well as base to apex RV strain and dyssynchrony were quantified using VVI in a total of 30 patients...

Spatial disorientation (SD) is one of the most severe causative factors in aviation accidents. We analyzed the reported SD episodes to evaluate the characteristics of severe SD in fighter pilots. Three hundred seventeen cases (95.5%) of 332 total valid cases experienced SD, and the ratio of night and day SD experiences (52.7% vs. 47.3%) (p < 0.05) shows a clear prevalence of night SD events. The severity of SD episodes at night (2.23 +/- 1.09) was higher than at day (1.89 +/- 1.04) (p < 0.01). In addition, the severity of visual illusions was significantly higher at night...

BACKGROUND: The Coriolis illusion produces spatial disorientation and is, therefore, dangerous for pilots. It is not known whether it also affects visual function (visual acuity and stereopsis). METHODS: There were 18 subjects (15 men and 3 women, mean age 24.7 yr) enrolled in the study. A spatial disorientation simulator was used to produce Coriolis stimulation. The visual acuity of the subjects was evaluated with the Rosenbaum Vision Card before and during Coriolis stimulation...

INTRODUCTION: The somatogravic illusion (SGI) is easily broken when the pilot looks out the aircraft window during daylight flight, but it has proven difficult to break or even reduce the SGI in non-pilots in simulators using synthetic visual scenes. Could visual-flow scenes that accommodate compensatory head movement reduce the SGI in naive subjects? METHODS: We investigated the effects of visual cues on the SGI induced by a human centrifuge. The subject was equipped with a head-tracked, head-mounted display (HMD) and was seated in a fixed gondola facing the center of rotation...

OBJECTIVE: We sought to improve understanding of visual perception in aviation to mitigate mishaps in approaches to landing. BACKGROUND: Research has attempted to identify the most salient visual cues for glide path performance in impoverished visual conditions. Numerous aviation accidents caused by glide path overestimation (GPO) have occurred when a low glide path was induced by a black hole illusion (BHI) in featureless terrain during night approaches. METHOD: Twenty pilots flew simulated approaches under various visual cues of random terrain objects and approach lighting system (ALS) configurations...

BACKGROUND: In aviation, vestibular-induced spatial disorientation is a significant cause of accidents. Recreating flight-like vestibular stimuli in simulators might be a means for training pilots to respond adequately in disorienting situations. Due to the physical constraints of land-based simulators, the question arises whether a given illusion may be created in different ways. For instance, is it possible to induce sensations of tilt by rotary stimuli? The present study concerns the relationship between sensations of rotation and tilt during complex vestibular stimulation...