Article

Discomfort from urban scenes: Metabolic consequences

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Abstract

Scenes from nature share in common certain statistical properties. Images with these properties can be processed efficiently by the human brain. Patterns with unnatural statistical properties are uncomfortable to look at, and are processed inefficiently, according to computational models of the visual cortex. Consistent with such putative computational inefficiency, uncomfortable images have been demonstrated to elicit a large haemodynamic response in the visual cortex, particularly so in individuals who are predisposed to discomfort. In a succession of five small-scale studies, we show that these considerations may be important in the design of the modern urban environment. In two studies we show that images from the urban environment are uncomfortable to the extent that their statistical properties depart from those of scenes from nature. In a third study we measure the haemodynamic response to images of buildings computed as having unnatural or natural statistical properties, and show that in posterior brain regions the images with unnatural statistical properties (often judged uncomfortable) elicit a haemodynamic response that is larger than for images with more natural properties. In two further studies we show that judgments of discomfort from real scenes (both shrubbery and buildings) are similar to those from images of the scenes. We conclude that the unnatural scenes in the modern urban environment are sometimes uncomfortable and place excessive demands on the neural computation involved in vision, with consequences for brain metabolism, and possibly also for health.

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... Similarly, electroencephalogram and brain imaging data indicated that nature compared to urban images evoked fewer or less demanding processes that are assumed to be related to early visual, attentional, and/or memory processes (Tang et al., 2017;Grassini et al., 2019). Similarly, when considering only urban environments, viewing buildings with more natural compared to unnatural properties was associated with less energy in visual brain areas (Le et al., 2017). As discussed in this latter study and further work including those on the PFA (Joye and van den Berg, 2011), these diverging processing demands may be caused by different properties of nature and urban images. ...
... It represents statistical scale invariance or regularity, which means that the characteristics of the image are relatively similar when zooming in and out of a scene. Likely because the human visual system is evolutionary (and partly ontogenetically) adapted to natural environments, images having respective properties, such as a specific spectral slope, are generally preferred and also found in aesthetic stimuli such as art, while deviating stimuli can lead to feelings of discomfort in the viewer (Redies, 2007;Graham and Field, 2009;Graham and Redies, 2010;Juricevic et al., 2010;Le et al., 2017). The spectral slope and derived measures are commonly used in visual perception research and empirical aesthetics to assess the "naturalness" of a given image. ...
... The spectral slope and derived measures are commonly used in visual perception research and empirical aesthetics to assess the "naturalness" of a given image. Thereby, it is generally found that spectral slopes similar to those found for natural scenes are associated with aesthetic perception and processing benefits, even across image types (e.g., Graham and Field, 2007b;Redies et al., 2007;Graham and Redies, 2010;Juricevic et al., 2010;Menzel et al., 2015Menzel et al., , 2017Penacchio and Wilkins, 2015;Spehar et al., 2015;Le et al., 2017). ...
Article
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Nature experiences usually lead to restorative effects, such as positive affective states and reduced stress. Even watching nature compared to urban images, which are known to differ in several image properties that are processed at early stages, can lead to such effects. One potential pathway explaining how the visual input alone evokes restoration is that image properties processed at early stages in the visual system evoke positive associations. To study these automatic bottom-up processes and the role of lower-level visual processing involved in the restoring effects of nature, we conducted two studies. First, we analyzed nature and urban stimuli for a comprehensive set of image properties. Second, we investigated implicit associations in a dichotomous set of nature and urban images in three domains, namely, valence, mood, and stress restoration. To examine the role of lower-level processing in these associations, we also used stimuli that lacked the spatial information but retained certain image properties of the original photographs (i.e., phase-scrambled images). While original nature images were associated with “good,” “positive mood,” and “restoration,” urban images were associated with “bad” and “stress.” The results also showed that image properties differ between our nature and urban images and that they contribute to the implicit associations with valence, although spatial information and therefore recognition of the environment remained necessary for positive associations. Moreover, lower-level processed image properties seem to play no or only minor roles for associations with mood and stress restoration.
... The increasing amount of time people spend indoors surrounded by Euclidean architecture produces visual strain because of the additional visual effort required to process more artificial spatial frequencies is suggested to lead to detrimental effects such as increased rates of headaches (Penacchio and Wilkins, 2015). Beyond alleviating physical discomfort, occupant stress levels can be minimized through fractal installations reminiscent of nature by reducing cognitive and visual strain produced by surrounding unnatural spatial frequencies (Taylor, 2006;Hagerhall et al., 2008;Le et al., 2017). These positive impacts of viewing fractals can be considered within the context of biophilia (Wilson, 1984) which recognizes the inherent need of humans to connect to nature. ...
... A 2-step clustering analysis identified no significant subgroups for pattern complexity. headaches, and overall stress resulting from additional effort exerted by the visual system to process more artificial patterns (Hagerhall et al., 2008;O'Hare and Hibbard, 2011;Penacchio and Wilkins, 2015;Le et al., 2017;Ogawa and Motoyoshi, 2020). Fractal patterns have the opportunity to combat these negative effects of unnatural environments by introducing easy to visually process natural patterns that can alter the occupants' experience of a space. ...
... The collaboration of design, physics, psychology, and technology provides a vital opportunity to test for and determine visual patterns that produce optimal perceptual responses and experiences in occupants of human-made structures. By selecting fractal patterns with D-values that are appropriate for particular built environments and mediums, instillations of these natural patterns have the opportunity to decrease eyestrain, headache rates, and stress (O'Hare and Hibbard, 2011;Penacchio and Wilkins, 2015;Le et al., 2017) in a large percentage of viewers Street et al., 2016;Pyankova et al., 2019) while potentially increasing the aesthetic experience of the space. ...
Article
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Highly prevalent in nature, fractal patterns possess self-similar components that repeat at varying size scales. The perceptual experience of human-made environments can be impacted with inclusion of these natural patterns. Previous work has demonstrated consistent trends in preference for and complexity estimates of fractal patterns. However, limited information has been gathered on the impact of other visual judgments. Here we examine the aesthetic and perceptual experience of fractal ‘global-forest’ designs already installed in humanmade spaces and demonstrate how fractal pattern components are associated with positive psychological experiences that can be utilized to promote occupant wellbeing. These designs are composite fractal patterns consisting of individual fractal ‘tree-seeds’ which combine to create a ‘global fractal forest.’ The local ‘tree-seed’ patterns, global configuration of tree-seed locations, and overall resulting ‘global-forest’ patterns have fractal qualities. These designs span multiple mediums yet are all intended to lower occupant stress without detracting from the function and overall design of the space. In this series of studies, we first establish divergent relationships between various visual attributes, with pattern complexity, preference, and engagement ratings increasing with fractal complexity compared to ratings of refreshment and relaxation which stay the same or decrease with complexity. Subsequently, we determine that the local constituent fractal (‘tree-seed’) patterns contribute to the perception of the overall fractal design, and address how to balance aesthetic and psychological effects (such as individual experiences of perceived engagement and relaxation) in fractal design installations. This set of studies demonstrates that fractal preference is driven by a balance between increased arousal (desire for engagement and complexity) and decreased tension (desire for relaxation or refreshment). Installations of these composite mid-high complexity ‘global-forest’ patterns consisting of ‘tree-seed’ components balance these contrasting needs, and can serve as a practical implementation of biophilic patterns in human-made environments to promote occupant wellbeing.
... Many researchers have also designed original questionnaires that focus on the overall visual discomfort, rather than the individual items [7], [8]. The objective measurements of visual discomfort include eye movements [1], electroencephalograph (EEG) [9], functional magnetic resonance imaging (fMRI) [10], and functional near infrared spectroscopy (fNIRS) [11], [12]. As an objective measurement, fNIRS can detect the haemodynamic response of cortex, including total haemoglobin (HbT), oxyhaemoglobin (HbO), and deoxyhaemoglobin (Hb). ...
... Increased neuronal activation leads to the increment in metabolic demands, and results in larger oxygen consumption [11], [15]. Some studies of visual discomfort have found out that uncomfortable visual stimuli could induce stronger haemodynamic response amplitude in the visual cortex [10]- [12]. Haigh et al. [11] have suggested that the positive correlation between haemodynamic response and visual discomfort is related to the metabolic load of visual cortex. ...
... Some studies on effects of image content have found that compared to other methods, the fNIRS is an effective and reliable indicator of visual discomfort. This measurement reflects the metabolic changes of the cortex clearly, and is sensitive to changes in visual discomfort [10]- [12]. The detailed comparison of brain activity measurements was listed in Table 1. ...
Article
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Display luminance is one of the most important factors that influence not only display performance but also visual discomfort greatly. To investigate the influence of display luminance and image content on visual discomfort, the haemodynamic response and subjective perception were recorded respectively when participants watched different visual stimuli. Different white levels (WLs) of display and images with different spatial amplitude spectra were adopted as the visual stimuli, and specific dark environment was applied in the study. The results showed that under dark ambient condition, the WL had significant influences on visual discomfort, which varied in images with different spatial amplitude spectra. The findings also indicated that, for visual discomfort measurement, the sensitivity of haemodynamic response was better than subjective evaluation.
... Moreover, Huang et al. (2003) indicated that migraineurs with visual aura are found to be highly susceptible to visual distortion caused by parallel lines or stripes and regularly spaced patterns, as can be seen in parametric architecture building forms and facades. The recent four studies conducted by Le et al. (2017) linked the effect of photographs of buildings and their modern urban settings that were sometimes uncomfortable to look at. The cortical hemodynamic response was of higher amplitude in response to urban images that had unnatural statistics and were uncomfortable. ...
... That is in line with the idea that the reaction induced by trypophobic stimuli reflects ancestral threat and has survival importance (Van Strien & Van der Peijl, 2018). Nevertheless, the aversion to the stimuli are still substantial enough to provoke a debate on the role of trypophobia in architecture and the urban environment as highlighted by Le et al. (2017). ...
Article
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New building materials and design technologies such as design parameterisation allow for the creation of unusual architectural elements composed of spatially repetitive patterns. Images with specific spatial properties, as from repetitive patterns, may cause psychological and physiological reactions, in some cases leading to severe discomfort, headaches or seizures. Clusters of roughly circular shapes, often hollow, are also known to create reactions such as sickness and vomiting in certain individuals. The phenomenon is known as trypophobia. Because trypophobia has only recently been described and is not widely recognised, we undertook a survey of the public reaction to trypophobic images, as well as to patterns that are known to have a neurological effect, viz. patterns of stripes. The study investigates whether the two types of pattern are similarly aversive and examines the extent of the aversion to find out whether trypophobia needs to be considered when designing buildings. We showed a variety of images to 405 members of the public to gauge their reaction. In some instances, the reaction was profound: one person vomited. The findings suggest that reactions to stimuli in the built environment are significant enough to provoke a debate on the role of visual discomfort in architecture and sustainable urbanism. It seems important to further investigate the properties of architectural shapes that induce discomfort so as to avoid a public health concern in contemporary urban environments.
... In computational models of the cortex, uncomfortable images have been shown to give rise to a response that is less sparse than for other images (Hibbard and O'Hare, 2015). Images that are uncomfortable usually evoke a large cortical hemodynamic response, measured using fMRI (Huang et al., 2003(Huang et al., , 2011 or near infrared spectroscopy (Haigh et al., 2013a(Haigh et al., , 2015Le et al., 2017), and a large electrical response measured in terms of steady state visual evoked potential (O'Hare, 2016;Haigh et al., 2019;Gentile and Aguirre, 2020;Lindquist et al., 2021) or alpha suppression (Haigh et al., 2018). Taken together, converging evidence suggests that specific deviations from the luminance profile typically found in natural scenes causes visual stress and can be associated with increased cortical activity. ...
... consistently from that expected in natural scenes. Uncomfortable stimuli also evoke large metabolic and electrophysiological responses (Huang et al., 2003(Huang et al., , 2011O'Hare, 2016;Le et al., 2017;Haigh et al., 2018Haigh et al., , 2019Gentile and Aguirre, 2020;Lindquist et al., 2021). The discomfort is theorized to serve as a homeostatic signal to avoid stimuli that are computationally and therefore metabolically demanding (Wilkins and Hibbard, 2014). ...
Article
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Visual discomfort is related to the statistical regularity of visual images. The contribution of luminance contrast to visual discomfort is well understood and can be framed in terms of a theory of efficient coding of natural stimuli, and linked to metabolic demand. While color is important in our interaction with nature, the effect of color on visual discomfort has received less attention. In this study, we build on the established association between visual discomfort and differences in chromaticity across space. We average the local differences in chromaticity in an image and show that this average is a good predictor of visual discomfort from the image. It accounts for part of the variance left unexplained by variations in luminance. We show that the local chromaticity difference in uncomfortable stimuli is high compared to that typical in natural scenes, except in particular infrequent conditions such as the arrangement of colorful fruits against foliage. Overall, our study discloses a new link between visual ecology and discomfort whereby discomfort arises when adaptive perceptual mechanisms are overstimulated by specific classes of stimuli rarely found in nature.
... This effect is observable on Figure 1.1-Middle, where the central ring from the reference stimulus (left) appears to be "greener" than the central ring from the test (right), which appears to be "bluer". Besides these effects, it is known that specific visual patterns (Figure 1.1-Right) can cause discomfort, malaise, nausea or even migraine [175,243]. The spatial properties of visual elements that compose the scene (whether are dense or sparse) and their relative contrast energy (due to its orientation, luminance, chromatic and spatial frequency distributions) can generate hyperexcitability in V1, a possible cause of visual discomfort for certain images. ...
... These responses will act as a contrast enhancement mechanism, which for the case of saliency, are integrated towards projections in the SC for eye movement control. Therewith, our model has also been able to reproducte visual discomfort, as relative contrast energy of particular region on a scene is found to produce hyperexcitability in V1 [175,243], one of possible causes of producing certain conditions such as malaise, nausea or even migraine. Previous neurodynamic [66,67,82,115,196] and saliency models [41,383] are able to reproduce attention processes and predict eye movements [53] but are uniquely presented to work for that specific task. ...
Thesis
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Humans move their eyes in order to learn visual representations of the world. These eye movements depend on distinct factors, either by the scene that we perceive or by our own decisions. To select what is relevant to attend is part of our survival mechanisms and the way we build reality, as we constantly react both consciously and unconsciously to all the stimuli that is projected into our eyes. In this thesis we try to explain (1) how we move our eyes, (2) how to build machines that understand visual information and deploy eye movements, and (3) how to make these machines understand tasks in order to decide for eye movements. (1) We provided the analysis of eye movement behavior elicited by low-level feature distinctiveness with a dataset of 230 synthetically-generated image patterns. A total of 15 types of stimuli has been generated (e.g. orientation, brightness, color, size, etc.), with 7 feature contrasts for each feature category. Eye-tracking data was collected from 34 participants during the viewing of the dataset, using Free-Viewing and Visual Search task instructions. Results showed that saliency is predominantly and distinctively influenced by: 1. feature type, 2. feature contrast, 3. temporality of fixations, 4. task difficulty and 5. center bias. From such dataset (SID4VAM), we have computed a benchmark of saliency models by testing performance using psychophysical patterns. Model performance has been evaluated considering model inspiration and consistency with human psychophysics. Our study reveals that state-of-the-art Deep Learning saliency models do not perform well with synthetic pattern images, instead, models with Spectral/Fourier inspiration outperform others in saliency metrics and are more consistent with human psychophysical experimentation. (2) Computations in the primary visual cortex (area V1 or striate cortex) have long been hypothesized to be responsible, among several visual processing mechanisms, of bottom-up visual attention (also named saliency). In order to validate this hypothesis, images from eye tracking datasets have been processed with a biologically plausible model of V1 (named Neurodynamic Saliency Wavelet Model or NSWAM). Following Li's neurodynamic model, we define V1's lateral connections with a network of firing rate neurons, sensitive to visual features such as brightness, color, orientation and scale. Early subcortical processes (i.e. retinal and thalamic) are functionally simulated. The resulting saliency maps are generated from the model output, representing the neuronal activity of V1 projections towards brain areas involved in eye movement control. We want to pinpoint that our unified computational architecture is able to reproduce several visual processes (i.e. brightness, chromatic induction and visual discomfort) without applying any type of training or optimization and keeping the same parametrization. The model has been extended (NSWAM-CM) with an implementation of the cortical magnification function to define the retinotopical projections towards V1, processing neuronal activity for each distinct view during scene observation. Novel computational definitions of top-down inhibition (in terms of inhibition of return and selection mechanisms), are also proposed to predict attention in Free-Viewing and Visual Search conditions. Results show that our model outperforms other biologically-inpired models of saliency prediction as well as to predict visual saccade sequences, specifically for nature and synthetic images. We also show how temporal and spatial characteristics of inhibition of return can improve prediction of saccades, as well as how distinct search strategies (in terms of feature-selective or category-specific inhibition) predict attention at distinct image contexts. (3) Although previous scanpath models have been able to efficiently predict saccades during Free-Viewing, it is well known that stimulus and task instructions can strongly affect eye movement patterns. In particular, task priming has been shown to be crucial to the deployment of eye movements, involving interactions between brain areas related to goal-directed behavior, working and long-term memory in combination with stimulus-driven eye movement neuronal correlates. In our latest study we proposed an extension of the Selective Tuning Attentive Reference Fixation Controller Model based on task demands (STAR-FCT), describing novel computational definitions of Long-Term Memory, Visual Task Executive and Task Working Memory. With these modules we are able to use textual instructions in order to guide the model to attend to specific categories of objects and/or places in the scene. We have designed our memory model by processing a visual hierarchy of low- and high-level features. The relationship between the executive task instructions and the memory representations has been specified using a tree of semantic similarities between the learned features and the object category labels. Results reveal that by using this model, the resulting object localization maps and predicted saccades have a higher probability to fall inside the salient regions depending on the distinct task instructions compared to saliency.
... Computational models of the visual system suggest that striped patterns reduce the sparseness, increasing "neural" activity (70). When images have an unnatural statistical structure they are aversive (71)(72)(73)(74) and patterns of stripes are perhaps the least natural of all visual stimuli. Measurements of images have been undertaken in terms of the Fourier amplitude spectrum (73), the orientation spectrum (75) and chromaticity difference (67) and images with statistics outside the range typical of natural images have been associated with discomfort. ...
... The mechanisms of pain in this context may well differ from those proposed here as explanations of migraine photophobia. Nevertheless, visual stimuli that give discomfort, pain or seizures are strong stimuli in the sense that they evoke a large cortical haemodynamic response in normal observers (5,48,74). Teleologically, discomfort and pain usually signal potential damage to the organism. It has been argued that visual discomfort is no different and may be a homeostatic response to reduce damaging hypermetabolism (78). ...
Article
Visual discomfort is related to the statistical regularity of visual images. The contribution of luminance contrast to visual discomfort is well understood and can be framed in terms of a theory of efficient coding of natural stimuli, and linked to metabolic demand. While color is important in our interaction with nature, the effect of color on visual discomfort has received less attention. In this study, we build on the established association between visual discomfort and differences in chromaticity across space. We average the local differences in chromaticity in an image and show that this average is a good predictor of visual discomfort from the image. It accounts for part of the variance left unexplained by variations in luminance. We show that the local chromaticity difference in uncomfortable stimuli is high compared to that typical in natural scenes, except in particular infrequent conditions such as the arrangement of colorful fruits against foliage. Overall, our study discloses a new link between visual ecology and discomfort whereby discomfort arises when adaptive perceptual mechanisms are overstimulated by specific classes of stimuli rarely found in nature.
... Computational models of the visual system suggest that striped patterns reduce the sparseness, increasing "neural" activity (70). When images have an unnatural statistical structure they are aversive (71)(72)(73)(74) and patterns of stripes are perhaps the least natural of all visual stimuli. Measurements of images have been undertaken in terms of the Fourier amplitude spectrum (73), the orientation spectrum (75) and chromaticity difference (67) and images with statistics outside the range typical of natural images have been associated with discomfort. ...
... The mechanisms of pain in this context may well differ from those proposed here as explanations of migraine photophobia. Nevertheless, visual stimuli that give discomfort, pain or seizures are strong stimuli in the sense that they evoke a large cortical haemodynamic response in normal observers (5,48,74). Teleologically, discomfort and pain usually signal potential damage to the organism. It has been argued that visual discomfort is no different and may be a homeostatic response to reduce damaging hypermetabolism (78). ...
Article
Full-text available
Photophobia is one of the most common symptoms in migraine, and the underlying mechanism is uncertain. The discovery of the intrinsically-photosensitive retinal ganglion cells which signal the intensity of light on the retina has led to discussion of their role in the pathogenesis of photophobia. In the current review, we discuss the relationship between pain and discomfort leading to light aversion (traditional photophobia) and discomfort from flicker, patterns, and colour that are also common in migraine and cannot be explained solely by the activity of intrinsically-photosensitive retinal ganglion cells. We argue that, at least in migraine, a cortical mechanism provides a parsimonious explanation for discomfort from all forms of visual stimulation, and that the traditional definition of photophobia as pain in response to light may be too restrictive. Future investigation that directly compares the retinal and cortical contributions to photophobia in migraine with that in other conditions may offer better specificity in identifying biomarkers and possible mechanisms to target for treatment.
... At the same time, the design of human settlements and buildings influences human health [28][29][30][31], suggesting that natural places can be thought of as healing places [32][33][34]. Typical urban settings are more discomforting, with metabolic and well-being consequences [35,36]. Exposure to nature reduces internal stress markers and produces healthier cortisol profiles [37,38]. ...
Article
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We propose a Green Mind Theory (GMT) to link the human mind with the brain and body, and connect the body into natural and social environments. The processes are reciprocal: environments shape bodies, brains, and minds, minds change body behaviours that shape the external environment. GMT offers routes to improved individual well-being whilst building towards greener economies. It builds upon research on green exercise and nature-based therapies, and draws on understanding derived fromneuroscience and brain plasticity, spiritual andwisdomtraditions, the lifeways of original cultures, and material consumption behaviours. We set out a simple metaphor for brain function: a bottom brain stem that is fast-acting, involuntary, impulsive, and the driver of fight and flight behaviours, a top brain cortex that is slower, voluntary, the centre for learning, and the driver of rest and digest. The bottom brain reacts before thought and directs the sympathetic nervous system. The top brain is calming, directing the parasympathetic nervous system. Here, we call the top brain blue and the bottombrain red, toomuch red brain is bad for health. Inmodern high-consumption economies, life has often come to be lived on red alert. An over-active red mode impacts the gastrointestinal, immune, cardiovascular, and endocrine systems. We develop our knowledge of nature-based interventions, and suggest a framework for the blue brain-red brain-green mind. We show how activities involving immersive-attention quieten internal chatter, how habits affect behaviours across the lifecourse, how long habits take to be formed and hard-wired into daily practice, the role of place making, and finally how green minds could foster prosocial and greener economies. We conclude with observations on twelve research priorities and health interventions, and ten calls to action.
... We believe an avenue to investigate this would be to start with the relationship between PPPD symptoms and visual discomfort to highly salient and cluttered images [28]. These images deviate from natural scene statistics and appear to overload the visual system both in imaging studies and computational models [29,52,[56][57][58][59]. Therefore, in the visual modality, we have a theoretical approach to overload that is less well developed in other modalities. ...
Article
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Background Persistent postural perceptual dizziness (PPPD) is a common chronic condition presenting in neurology and neuro-otology clinics. Symptoms lie on a spectrum in the general population. The cause is unknown and thought to involve interactions between visual and vestibular systems, but symptoms also correlate with anxiety and migraine.Objective To test whether PDDD symptoms are associated with reported differences in other senses (touch, hearing, smell and taste); to investigate possible mediation via anxiety or migraine; to discover the proportion of variance accountable to these non-vestibular factors.Methods We measured self-report multisensory sensitivity, anxiety, visual difficulties, visual discomfort and migraine in patients with PPPD (N = 29) and a large general population cohort (N > 1100). We used structural equation modelling to examine relationships between the factors using a step-wise approach.ResultsWe found increased self-reported over-sensitivity in sensory domains beyond vision and balance in both patients with PPPD and non-clinical participants with more PPPD symptoms. SEM analysis revealed that anxiety partly, but not wholly, mediated this relationship. Adding visual difficulties and visual discomfort to the model allowed it to explain 50% of PPPD symptom variance. Most of the path coefficients and mediation effects in our model were unchanged between participants with and without migraine.Conclusions Our findings support the idea that PPPD is a complex neurological condition that includes broad perceptual factors, and may suggest that some brains are predisposed to generalised cross-modal sensory-overload. This may give rise to vulnerability to severe PPPD should a vestibular insult occur.
... The urbanicity effect was tested by Corcoran et al. (2017), who found that even just briefly looking at photos of desirable or undesirable landscapes (urban or rural) had some effect on participants' anticipations of threat, which is linked with increased depression, anxiety, and paranoia. Others have presented evidence that the geometric and statistical properties of repetitive patterns found in urban landscapes in contrast to those exhibited in natural scenes produce feelings of visual and cognitive discomfort (Le et al. 2017). Several stressors in the built environment have been identified, including noise, crowding, housing type and quality, light, and air quality (Evans 2003). ...
Article
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Urbanicity has long been associated with stress, anxiety, and mental disorders. A new field of neurourbanism addresses these issues, applying neuroscience laboratory methods to tackle global urban problems and promote happier and healthier cities. Exploratory studies have trialed psychophysiological measurement beyond laboratories, capitalizing on the availability of biosensing technologies to capture geo-located physiological markers of emotional responses to urban environments. This article reviews the emerging conceptual and methodological debates for urban stress research. City authorities increasingly favor new data-driven and technology-enabled approaches to governing smart cities, with the aim that governments will be enabled to pursue evidence-based urban well-being policies. Yet there are few signs that our cities are undergoing the transformative, structural changes necessary to promote well-being. To face this urgent challenge and to interrogate the technological promises of our future cities, this article advances the conceptual framework of critical neurogeography and illustrates its application to a comparative international study of urban workers. It is argued that biosensing data can be used to elicit socially and politically relevant narrative data that centers on body–mind–environment relations but exceeds the individualistic and often behaviorist confines that have come to be associated with the quantifying technologies of the emerging field of neurourbanism.
... Computational models suggest that detrimental patterns and images with unnatural statistics are processed less efficiently by the brain as they cause a denser response (more neurons firing at the same time) in the visual system (Hibbard & O'Hare, 2015;Penacchio et al., 2016), which can be at the origin of visual discomfort. Le et al. (2017) reported that images of urban scenes with statistical properties that deviate from the typical statistical properties of natural scenes were associated with a higher haemodynamic response in the visual cortex. They also found that judgments of visual discomfort from real scenes were matched to judgments from images of these scenes, suggesting that this measure could be integrated into the design practice of urban scenes to avoid constructions with detrimental consequences for brain metabolism, and also for health and wellbeing. ...
Chapter
The methods of paired comparison and ranking play an important role in the analysis of preference data. In this study, first we show how asymmetric multidimensional scaling allows to represent in a diagram the preference order that comes out in a paired-comparison task concerning architectural façades. A ranking task involving the same stimuli and the same subject sample further enriched the preference analysis, because multidimensional unfolding applied to the ranking data matrix allows to detect the relationships between subjects and architectural façades. The results show that high curved façade is the most preferred, followed by the medium curved, angular and rectilinear ones. Rectilinear stimuli were always the least preferred and not angularity as expected.
... Computational models suggest that detrimental patterns and images with unnatural statistics are processed less efficiently by the brain as they cause a denser response (more neurons firing at the same time) in the visual system (Hibbard & O'Hare, 2015;Penacchio et al., 2016), which can be at the origin of visual discomfort. Le et al. (2017) reported that images of urban scenes with statistical properties that deviate from the typical statistical properties of natural scenes were associated with a higher haemodynamic response in the visual cortex. They also found that judgments of visual discomfort from real scenes were matched to judgments from images of these scenes, suggesting that this measure could be integrated into the design practice of urban scenes to avoid constructions with detrimental consequences for brain metabolism, and also for health and wellbeing. ...
Article
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Can curvature drive preference, perceived familiarity, complexity, stability and approachability for architectural façades? In this study, we generated four versions of the same reference building, varying only the amount of curvature introduced in the façade. Participants’ judgments were measured using three experimental methodologies. Multidimensional scaling on forced choices showed that the curved façade was the most preferred. Multidimensional unfolding on ranking task showed that the majority of participants expressed higher preferences for the curved façade compared to the sharp-angled and rectilinear ones. Ratings on different psychological variables provided supporting evidence for curvature significantly influencing liking and approachability judgments. Results from image analyses –using a dynamical model of the visual cortex and a model that characterizes discomfort in terms of adherence to the statistics of natural images – matched behavioural data. We discuss the implications of the findings on our understanding of human preferences, which are intrinsically dynamic and influenced by context and experience.
... Second, participants in former neural imaging studies reported severe nausea symptoms after exposing to VIMS-provoking stimuli (Farmer et al., 2015;Miyazaki et al., 2015;Napadow et al., 2013). Since visually-induced nausea is linked to massive increases in the cortical hemodynamic response (Le et al., 2017;Wilkins, 2016), it can introduce confounding effects on the reported cortical BOLD responses (Farmer et al., 2015;Napadow et al., 2013) and inter-hemispheric desynchronization (Miyazaki et al., 2015). Consequently, it is necessary to control for both the onset of vection and nausea. ...
Article
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Visually induced motion sickness (VIMS) can occur via prolonged exposure to visual stimulation that generates the illusion of self-motion (vection). Not everyone is susceptible to VIMS and the neural mechanism underlying susceptibility is unclear. This study explored the differences of electroencephalographic (EEG) signatures between VIMS-susceptible and VIMS-resistant groups. Thirty-two-channel EEG data were recorded from 12 VIMS-susceptible and 15 VIMS-resistant university students while they were watching two patterns of moving dots: (1) a coherent rotation pattern (vection-inducing and potentially VIMS-provoking pattern), and (2) a random movement pattern (non-VIMS-provoking control). The VIMS-susceptible group exhibited a significantly larger increase in the parietal N2 response when exposed to the coherent rotating pattern than when exposed to control patterns. In members of the VIMS-resistant group, after vection onset, global connectivity from all other EEG electrodes to the right-temporal-parietal and to the right-central areas increased, whereas the global connectivity to the right-frontal area reduced. Such changes were not observed in the susceptible group. Further, the increases in N2 amplitude and the identified phase synchronization index were significantly correlated with individual motion sickness susceptibility. Results suggest that VIMS susceptibility is associated with systematic impairment of dynamic cortical coordination as captured by the phase synchronization of cortical activities. Analyses of dynamic EEG signatures could be a means to unlock the neural mechanism of VIMS.
... It is now possible to make predictions about visual discomfort from images using Penacchio and Wilkins' algorithm by comparing the spatial structure of an image to natural scenes, by analysing its difference in colour, as well as by relating it to the sensitivity of human visual system. 68,69 With the technological advances in eye tracking, pattern recognition and augmented reality, it would not be a surprise if, in the near future, a robotic eye might be developed capable of replicating human eye movements and of capturing and analysing visual images simultaneously. ...
Article
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This paper presents experimental approaches for evaluating concert lighting from the viewpoints of audience members and performers in Cambridge King's College Chapel. We develop image zoning and abstraction techniques to quantify and interpret photometric data acquired under four different electric lighting conditions. Assessed by 78 participants, these lighting scenarios are compared across six different viewing positions using a set of structured questionnaires. Ordered logistic regression modelling shows that the ratios and functions describing uniformity, brightness and light patterns are common explanatory variables for predicting perceived visual clarity, visual uniformity, brightness and spatial intimacy. Uniformity-related attributes are observed to be among the strongest variables for all these perceived qualities, except for visual clarity, which is better explained by acuity-related measures. These experimental results confirm the applicability of our approaches, highlighting the importance of combining multiple methods and integrating complex architectural situations into the process of understanding luminous appearance.
... Latest experiments showed that our model is also able to predict visual discomfort [60]. Specific visual patterns ( Fig. 1C) are shown to cause discomfort, malaise, nausea or even migraine [59] [38]. Taking into account the relative contrast energy from stimulus regions (due to its orientation, luminance, chromatic and spatial frequency distributions), we can predict whether a stimulus can cause hyperexcitability in V1, a possible cause of visual discomfort for certain images. ...
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Computations in the primary visual cortex (area V1 or striate cortex) have long been hypothesized to be responsible, among several visual processing mechanisms, of bottom-up visual attention (also named saliency). In order to validate this hypothesis, images from eye tracking datasets are processed with a biologically plausible model of V1 able to reproduce other visual processes such as brightness, chromatic induction and visual discomfort. Following Li's neurodynamic model, we define V1's lateral connections with a network of firing rate neurons, sensitive to visual features such as brightness, color, orientation and scale. The resulting saliency maps are generated from the model output, representing the neuronal activity of V1 projections towards brain areas involved in eye movement control. Our predictions are supported with eye tracking experimentation and results show an improvement with respect to previous models as well as consistency with human psychophysics. We propose a unified computational architecture of the primary visual cortex that models several visual processes without applying any type of training or optimization and keeping the same parametrization.
... It goes beyond the scope of this article to fully discuss the issue in this field, but it is worth noting the two main hypotheses advanced to explain this phenomenon: (1) that preference for curvature is a result of disliking for sharpness; (2) that curved forms are easier for the human visual system to process and therefore more comfortable to view (for a review on this issue see [84]). Penacchio and Wilkins [85] found that curvilinear images are more comfortable to look at compared to pictures with sharp or linear shapes and Le et al. [86] found the same results both when they measured visual discomfort in laboratory and real space conditions, looking directly at urban scenes. We suggest that NP may have a more natural distribution of curvature compared to the other perspectives. ...
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Following its discovery in fifteenth-century Italy, linear perspective has often been hailed as the most accurate method of projecting three-dimensional visual space onto a two-dimensional picture plane. However, when we survey the history of European art it is evident that few artists fully complied with its mathematical rules, despite many of them being rigorously trained in its procedures. In this paper, we will consider how artists have actually depicted visual space, and present evidence that images created according to a “natural” perspective (NP) used by artists are judged as better representations of visual space than those created using standard linear (LP) and curvilinear fisheye (FP) projective geometries. In this study, we built a real three-dimensional scene and produced photographs of the scene in three different perspectives (NP, LP and FP). An online experiment in which we asked people to rank the perspectives in order of preference showed a clear preference for NP compared to the FP and LP. In a second experiment, participants were asked to view the real scene and rate each perspective on a range of psychological variables. Results showed that NP was the most preferred and the most effective in depicting the physical space naturally. We discuss the implications of these results and the advantages and limitations of our approach for studying the global metric and geometrical structure of visual space.
... Urban scenes violate the rule of nature: buildings tend to have regular, repetitive patterns due to the common use of design features such as unnatural landscapes, transportation systems and faulty restorations. There are studies [40,41] in which the natural landscape structures positively affect the human brain. However, it is quite interesting that as a contribution to all studies, landscape areas also prefer "more colorful" areas of spring. ...
... Not only can the 'cone model' predict discomfort, but it also predicts the oxygenation of the cortex in response to images. 71 This suggests that images that are unnatural and uncomfortable demand greater oxygenation. As will now be shown, this is precisely what one might expect from computational models of the visual cortex, which suggest that natural (and comfortable) images are processed efficiently by the neural machinery of the visual cortex, as shown by Field. ...
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Visual discomfort refers to discomfort or pain in or around the eyes, often associated with headache and/or nausea, and sometimes accompanied by signs such as red, itchy or watering eyes. The lighting conditions likely to cause visual discomfort are insufficient light for the task at hand, dramatic differences in illuminance around the task, shadows, veiling reflections, glare and flicker. To date, research on visual discomfort has been largely reactive, i.e. in response to complaints, but there is now proactive work that explores why discomfort occurs. The hypothesis underlying this work is that the human visual system has evolved to extract information from the natural world efficiently so that when the visual environment departs from the temporal, spatial or chromatic characteristics of the natural world, discomfort is likely because of inefficient neural processing. An important implication is that visual discomfort therefore depends on both the lighting and the décor of a space. Until this approach becomes more established, visual discomfort can be minimised by following carefully developed standards and guidance, by using products that meet appropriate standards, by paying attention to both lighting and décor and by being aware of the wide variation in individual sensitivity.
... In modern urban life, we are continuously exposed to unnatural and artificial visual stimuli, which can appear uncomfortable and can even induce photosensitive seizures, headache, and migraine (Le et al., 2017). With the development of computer animation techniques and practical applications, such symptoms may occur more frequently. ...
Article
Flickering lights can be uncomfortable to look at and can induce seizures in observers with photosensitive epilepsy. However, the temporal characteristics contributing to these effects are not fully known. In the spatial domain, one identified source of visual discomfort is when images have Fourier amplitude spectra that deviate from the natural (∼1/frequency, 1/f) statistical characteristics of natural scenes, especially if they contain excess energy at the medium frequencies at which the visual system is most sensitive. We tested for analogous effects in the temporal domain, manipulating both the amplitude and phase spectra of the flicker. Participants judged the relative discomfort of temporal luminance variations in a pair of uniform 17° fields with different temporal modulations. In general, discomfort increased with deviations from natural amplitude spectra, particularly those with excess energy at medium frequencies or biased toward sharper spectra. These ratings of discomfort were also consistent with ratings of how natural the modulations appeared. However, the temporal discomfort judgments were also strongly affected by the phase spectra of the flicker, with fixed vs. random spectra producing very different responses. This was not due to the perceived regularity or predictability of the flicker, but could arise from a number of other potential factors. Our findings suggest that, like spatial patterns, visual discomfort in time-varying patterns depends in part on how similar they are to the amplitude spectra of temporal variations in the natural visual environment, but also point to the critical role of the phase spectrum in the perceived discomfort of flicker.
... Flickering light and stressful patterns are unnatural, uncomfortable, and a common feature of the modern urban environment. [19][20][21][22] ...
... The images were all captured at a minimum resolution of 300 dpi. 38, II ...
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Background: Understanding more about the unseen side of our responses to visual stimuli offers a powerful new tool for transportation planning. Traditional transportation planning tends to focus on the mobility of vehicles rather than on opportunities to encourage sustainable transport modes, like walking. Methods: Using eye-tracking emulation software, this study measured the unconscious visual responses people have to designs and layouts in new built environments, focusing on what makes streets most walkable. Results: The study found key differences between the way the brain takes in conventional automobile-oriented residential developments versus new urbanist layouts, with the former lacking key fixation points. Conclusion: The study's discoveries significantly explain why new urbanist layouts promote walking effortlessly and conventional automobile-oriented residential developments cannot.
... These responses will act as a contrast enhancement mechanism, which for the case of saliency, are integrated towards projections in the superior colliculus (SC) for eye movement control. Therewith, our model has also been able to reproduce visual discomfort, as relative contrast energy of particular region on a scene is found to produce hyperexcitability in V1 [38,39], one of possible causes of producing certain conditions such as malaise, nausea or even migraine. Previous neurodynamic [40][41][42][43][44][45] and saliency models [8,9,46] have been able to predict eye movements. ...
Article
Previous studies suggested that lateral interactions of V1 cells are responsible, among other visual effects, of bottom-up visual attention (alternatively named visual salience or saliency). Our objective is to mimic these connections with a neurodynamic network of firing-rate neurons in order to predict visual attention. Early visual subcortical processes (i.e. retinal and thalamic) are functionally simulated. An implementation of the cortical magnification function is included to define the retinotopical projections towards V1, processing neuronal activity for each distinct view during scene observation. Novel computational definitions of top-down inhibition (in terms of inhibition of return, oculomotor and selection mechanisms), are also proposed to predict attention in Free-Viewing and Visual Search tasks. Results show that our model outpeforms other biologically inspired models of saliency prediction while predicting visual saccade sequences with the same model. We also show how temporal and spatial characteristics of saccade amplitude and inhibition of return can improve prediction of saccades, as well as how distinct search strategies (in terms of feature-selective or category-specific inhibition) can predict attention at distinct image contexts.
... Our own research has demonstrated significant increases in detection sensitivity, attention, visual performance (e.g., pattern recognition and navigation), aesthetic appeal and stressreduction. Conversely, the lack of fractal aesthetics in unnatural (man-made) environments puts a strain on the visual system, inducing negative responses such as headaches [98]. ...
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Fractal objects are prevalent in natural scenery. Their repetition of patterns at increasingly fine magnifications creates a rich complexity. Fractals displaying mid-range complexity are the most common and include trees, clouds, and mountains. The “fractal fluency” model states that human vision has adapted to process these mid-range fractals with ease. I will first discuss fractal fluency and demonstrate how it enhances the observer’s visual capabilities by focusing on experiments that have important practical consequences for improving the built environment. These enhanced capabilities generate an aesthetic experience and physiological stress reduction. I will discuss strategies for integrating fractals into building designs to induce positive impacts on the observer. Examples include fractal solar panels, fractal window shades, and fractal floor patterns. These applications of fractal fluency represent a fundamental and potentially impactful form of salutogenesis.
... 193 In healthy individuals, such unnatural stimuli generate both visual discomfort and a large hemodynamic response. 194 Haigh and others showed that images with a large chromaticity difference (rare in nature) also evoked discomfort and a large hemodynamic response, and they interpreted the differences between the epileptogenic properties of colored flicker 195 in these terms. 196,197 A large neural response, possibly due to failure of gain control, 198 is necessary for a PPR, but it is not sufficient. ...
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Light flashes, patterns, or color changes can provoke seizures in up to 1 in 4000 persons. Prevalence may be higher because of selection bias. The Epilepsy Foundation reviewed light‐induced seizures in 2005. Since then, images on social media, virtual reality, three‐dimensional (3D) movies, and the Internet have proliferated. Hundreds of studies have explored the mechanisms and presentations of photosensitive seizures, justifying an updated review. This literature summary derives from a nonsystematic literature review via PubMed using the terms “photosensitive” and “epilepsy.” The photoparoxysmal response (PPR) is an electroencephalography (EEG) phenomenon, and photosensitive seizures (PS) are seizures provoked by visual stimulation. Photosensitivity is more common in the young and in specific forms of generalized epilepsy. PS can coexist with spontaneous seizures. PS are hereditable and linked to recently identified genes. Brain imaging usually is normal, but special studies imaging white matter tracts demonstrate abnormal connectivity. Occipital cortex and connected regions are hyperexcitable in subjects with light‐provoked seizures. Mechanisms remain unclear. Video games, social media clips, occasional movies, and natural stimuli can provoke PS. Virtual reality and 3D images so far appear benign unless they contain specific provocative content, for example, flashes. Images with flashes brighter than 20 candelas/m2 at 3‐60 (particularly 15‐20) Hz occupying at least 10 to 25% of the visual field are a risk, as are red color flashes or oscillating stripes. Equipment to assay for these characteristics is probably underutilized. Prevention of seizures includes avoiding provocative stimuli, covering one eye, wearing dark glasses, sitting at least two meters from screens, reducing contrast, and taking certain antiseizure drugs. Measurement of PPR suppression in a photosensitivity model can screen putative antiseizure drugs. Some countries regulate media to reduce risk. Visually‐induced seizures remain significant public health hazards so they warrant ongoing scientific and regulatory efforts and public education.
... The salutogenic effect of multiple fractal environments can contribute to recovery from physical or mental illness or injury. Conversely, the lack of fractal aesthetics in unnatural environments puts a strain on the visual system, inducing negative responses such as headaches [137]. ...
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This article reviews current research in visual urban perception. The temporal sequence of the first few milliseconds of visual stimulus processing sheds light on the historically ambiguous topic of aesthetic experience. Automatic fractal processing triggers initial attraction/avoidance evaluations of an environment’s salubriousness, and its potentially positive or negative impacts upon an individual. As repeated cycles of visual perception occur, the attractiveness of urban form affects the user experience much more than had been previously suspected. These perceptual mechanisms promote walkability and intuitive navigation, and so they support the urban and civic interactions for which we establish communities and cities in the first place. Therefore, the use of multiple fractals needs to reintegrate with biophilic and traditional architecture in urban design for their proven positive effects on health and well-being. Such benefits include striking reductions in observers’ stress and mental fatigue. Due to their costs to individual well-being, urban performance, environmental quality, and climatic adaptation, this paper recommends that nontraditional styles should be hereafter applied judiciously to the built environment.
... Latest experiments showed that this computational architecture is also able to predict visual discomfort (Penacchio et al., 2016). Specific visual patterns (see Figure 1C) are shown to cause discomfort, malaise, nausea, or even migraine (Penacchio & Wilkins, 2015;Le et al., 2017). Taking into account the relative contrast energy from stimulus regions (due to its orientation, luminance, chromatic, and spatial frequency distributions), we can predict whether a stimulus can cause hyperexcitability in V1, a possible cause of visual discomfort for certain images. ...
Article
Lateral connections in the primary visual cortex (V1) have long been hypothesized to be responsible for several visual processing mechanisms such as brightness induction, chromatic induction, visual discomfort, and bottom-up visual attention (also named saliency). Many computational models have been developed to independently predict these and other visual processes, but no computational model has been able to reproduce all of them simultaneously. In this work, we show that a biologically plausible computational model of lateral interactions of V1 is able to simultaneously predict saliency and all the aforementioned visual processes. Our model's architecture (NSWAM) is based on Penacchio's neurodynamic model of lateral connections of V1. It is defined as a network of firing rate neurons, sensitive to visual features such as brightness, color, orientation, and scale. We tested NSWAM saliency predictions using images from several eye tracking data sets. We show that the accuracy of predictions obtained by our architecture, using shuffled metrics, is similar to other state-of-the-art computational methods, particularly with synthetic images (CAT2000-Pattern and SID4VAM) that mainly contain low-level features. Moreover, we outperform other biologically inspired saliency models that are specifically designed to exclusively reproduce saliency. We show that our biologically plausible model of lateral connections can simultaneously explain different visual processes present in V1 (without applying any type of training or optimization and keeping the same parameterization for all the visual processes). This can be useful for the definition of a unified architecture of the primary visual cortex.
... Natural scenes and images that share these properties require less neural energy to process -perhaps because they are the environments in which we evolved and developed to perceive [19,20,46,60]. Images that deviate from these statistical properties appear to be processed less efficiently: they are discriminated less well [22,35,47], they are subordinate in binocular rivalry [3], and they tend to produce a larger neural response [28,38]. ...
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Background: Images that deviate from natural scene statistics in terms of spatial frequency and orientation content can produce visual stress (also known as visual discomfort), especially for migraine sufferers. These images appear to over-activate the visual cortex. Objective: To connect the literature on visual discomfort with a common chronic condition presenting in neuro-otology clinics known as persistent postural perceptual dizziness (PPPD). Sufferers experience dizziness when walking through highly cluttered environments or when watching moving stimuli. This is thought to arise from maladaptive interaction between vestibular and visual signals for balance. Methods: We measured visual discomfort to stationary images in patients with PPPD (N = 30) and symptoms of PPPD in a large general population cohort (N = 1858) using the Visual Vertigo Analogue Scale (VVAS) and the Situational Characteristics Questionnaire (SCQ). Results: We found that patients with PPPD, and individuals in the general population with more PPPD symptoms, report heightened visual discomfort to stationary images that deviate from natural spectra (patient comparison, F (1, 1865) = 29, p < 0.001; general population correlations, VVAS, rs (1387) = 0.46, p < 0.001; SCQ, rs (1387) = 0.39, p < 0.001). These findings were not explained by co-morbid migraine. Indeed, PPPD symptoms showed a significantly stronger relationship with visual discomfort than did migraine (VVAS, zH = 8.81, p < 0.001; SCQ, zH = 6.29, p < 0.001). Conclusions: We speculate that atypical visual processing -perhaps due to a visual cortex more prone to over-activation -may predispose individuals to PPPD, possibly helping to explain why some patients with vestibular conditions develop PPPD and some do not.
... A number of previous studies on static stimuli commonly suggest that a feeling of unpleasantness, or discomfort, is essentially brought by visual stimuli that deviate from the statistical regularity of a natural image in terms of spatial frequency spectrum (Cole & Wilkins, 2013;Fernandez & Wilkins, 2008;Juricevic et al., 2010;O'Hare & Hibbard, 2011;Spehar & Taylor, 2013;Spehar et al., 2016;Viengkham et al., 2019;Viengkham & Spehar, 2018;Wilkins, 1995;Wilkins et al., 1984) and of orientation spectrum (Ogawa & Motoyoshi, 2020). Such deviation can reduce the efficiency of visual processing and increase the neural work load, as supported by evidence showing that the enhanced hemodynamic response is correlated to the subjective discomfort of a visual stimulus (Bargary et al., 2015;Le et al., 2017). ...
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Recent psychophysical evidence shows that visual discomfort and unpleasantness are related to particular image features such as the spatial frequency and orientation spectrum. We also have a strong unpleasant feeling toward moving objects such as swarming worms, but it is poorly understood how motion information relates to a feeling of unpleasantness. The present study investigated spatiotemporal frequency characteristics that cause visual unpleasantness using bandpass noise with variable spatial frequencies, temporal frequencies, temporal frequency bandwidths, and orientation bandwidths. Results show that dynamic noise with relatively low temporal frequencies (0.5–2 Hz) was markedly more unpleasant than static noise, including that judged as the most unpleasant in a previous study. Remarkably, translational motion of the noise did not increase the feeling of unpleasantness. A subsequent experiment using a dynamic texture in which elements moved in a variable range of random directions showed that the variegated motion direction plays a critical role in promoting visual unpleasantness. Natural scenes have regularity in that features inside an object usually move in the same direction and rarely at random, and the present results further support the notion that deviation from the statistical regularity of natural scenes in images and movies induces negative emotions.
... For example, research has shown that image salience can play a role in view preference 20 and visual comfort. Le et al. 90 showed that unnatural properties of urban scene images (e.g. repetitive patterns) resulted in higher discomfort, as reflected by a relatively large haemodynamic response in the visual cortex. ...
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With people spending up to 90% of their time in indoor spaces, windows and the visual connection that they afford to the outside, can play an important role in ensuring physical and psychological well-being. This is particularly relevant in urban settings, a substantial part of our lives, whilst still being significantly understudied. What we know from other environments may not translate to cities, and there may be important differences between the expressed preferences of individuals and their behaviour. Therefore, this study sought to define suitable methods and metrics to measure view preference in urban environments. Participants were asked to observe urban views whilst three types of data were collected: subjective preference ratings; eye-tracking measures and verbal reasoning. We found that when views were preferred, the gaze of the observers was more exploratory, with a higher occurrence of fixations and number of saccades. In addition, participants tend to prefer the presence of people, well-maintained buildings and orderly presented colours. A new link was revealed between the degree of visual exploration and the preference rating of a visual scene. This characteristic pattern of oculomotor behaviour may guide the criteria for framing selected views and accordingly inform window design in buildings.
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The goal of the current research was to compare the effects of physical versus virtual nature experience on stress and well-being. Previous research suggests that an immersive nature experience can be beneficial for health, but direct comparisons between physical and virtual reality (VR) experiences are scarce. In the current Study, fifty participants navigated self-paced through a forest scene that was either an immersive VR forest or a physical forest. Before and after the intervention, we measured positive and negative affect, subjective vitality, and perceived daily stress. After the intervention, we measured perceived restorative outcomes. Results revealed that both VR and physical nature experience resulted in expected restorative effects: Affect was more positive and less negative, subjective vitality increased slightly, and stress decreased slightly after both interventions. There were only marginal effects with regard to restoration between the two settings. Overall, these findings suggest that immersive VR nature experiences can have restoration effects similar to physical nature experiences, suggesting intervention strategies when physical nature options are scarce.
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This special issue is the first systematic introduction to the progress of landsenses ecology and its applications since its formation in 2016. As a people-oriented, science-technology-based emerging discipline, landsenses ecology connects our physical senses with digital sensors, and balances the local and global considerations of ecosystem services and sustainable development. The progress in landsenses ecology research and applications covered by the 14 papers in this special issue is preliminary but outstanding. In particular, this special issue clarifies fundamental concepts, introduces technical methods, and demonstrates application cases of landsenses ecology. These efforts may help people with different cultural and disciplinary experiences consistently identify and apply this new scientific discipline.
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Flicker has been an important lighting system consideration for over a century. More precise terms are temporal light modulation (TLM) as the stimulus, and responses to TLM as the unwanted visual, cognitive, or physiological consequences. As lighting technology evolved, different forms of TLM emerged, and so did responses to them. Today, some LED systems – encompassing the LED, driver, and control – can result in TLM causing severe unwanted effects, while other LED systems produce no unwanted effects at all. LED systems can deliver a much wider range of luminous waveforms than conventional lighting systems, some exhibiting very high modulation depths. More than any light source before, they can elicit perceptions of the phantom array. Direct flicker effects at modulation frequencies less than about 80 Hz and the stroboscopic effect at frequencies greater than 80 Hz are fairly well understood, but the phantom array effect needs more exploration and characterisation. This review focuses on the technology and research history that led to current metrics for quantifying TLM and human responses to TLM. Visually impaired individuals may exhibit alterations in their response to TLM, but such a discussion is beyond the intent of this review. Thus, the focus is on individuals with normal visual function.
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The human brain is designed as a social engagement system hard-wired to take in and respond to other people. This study begins to explore how this hidden brain design also directs our engagement with the built environment, in this instance, determining our behaviour around buildings. Using eye-tracking emulation software, this study tracked the unconscious responses people have to new-urbanist and more typical, car-centric suburban American house facades (elevations). It found that this kind of emulation software can help demonstrate how new urbanist homes and streetscapes were implicitly easier for people to take in and focus on, than those in car-centric subdivisions. The implications of these findings are that urban designers and architects can employ eye-tracking emulation software to explore the ways that humans unconsciously handle visual stimuli, subject to validation from alternative data sources.
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The human visual system evolved to process images from nature. Natural images include images of jungles, deserts and woodlands, but despite the very obvious differences in the image content, all such images have in common three important properties. First, there is little flicker; second, there is a characteristic luminance structure, which can be expressed in terms of the Fourier amplitude spectrum; third, the lighting chromaticity lies on the Planckian locus (red when the sun is setting, white at midday and blue when the sunlight is scattered). We will consider each of these characteristics in turn and show that the properties of scenes from the modern urban environment often differ from those in nature, and that when they do, the scenes are associated with discomfort, particularly for individuals who experience migraine with aura. Flicker There is little flicker in natural scenes-the variation in luminance is circadian or the result of movement. In marked contrast flicker is pervasive in the modern urban environment. Flicker at frequencies in the range 4-70Hz can evoke seizures in patients with photosensitive epilepsy (Harding & Harding 2010). Flicker at these frequencies is provided when switch-start compact fluorescent lamps are ignited. The lamps are often used in toilets and turned on by occupancy sensors, and so people (including those who are photosensitive) have no opportunity of avoiding the flicker. Flicker from fluorescent lamps occurs not only when they are first ignited, but continues after ignition. The frequency of the flicker depends on the circuitry controlling the lamp. When the lamps are controlled by magnetic ballast, as was Abstract The statistical characteristics of visual images that provoke discomfort generally differ from those of images found in nature. Computational models of the cortex suggest that uncomfortable images are processed inefficiently, a suggestion consistent with the large electrical and haemodynamic cortical response such images induce. The response is greater in individuals who customarily experience visual discomfort, such as those with migraine. Text provides an unnatural image and can be uncomfortable when small and closely spaced. It can provoke illusions of color, shape and motion, just as do patterns of stripes, and these illusions can disturb reading and reading acquisition. Changing the lighting chromaticity can sometimes reduce these illusions, particularly in patients with migraine aura, thereby facilitating reading.
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Previous studies in that line suggested that lateral interactions of V1 cells are responsible, among other visual effects, of bottom-up visual attention (alternatively named visual salience or saliency). Our objective is to mimic these connections in the visual system with a neurodynamic network of firing-rate neurons. Early subcortical processes (i.e. retinal and thalamic) are functionally simulated. An implementation of the cortical magnification function is included to define the retinotopical projections towards V1, processing neuronal activity for each distinct view during scene observation. Novel computational definitions of top-down inhibition (in terms of inhibition of return and selection mechanisms), are also proposed to predict attention in Free-Viewing and Visual Search conditions. Results show that our model outpeforms other biologically-inpired models of saliency prediction as well as to predict visual saccade sequences during free viewing. We also show how temporal and spatial characteristics of inhibition of return can improve prediction of saccades, as well as how distinct search strategies (in terms of feature-selective or category-specific inhibition) predict attention at distinct image contexts.
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Sensory stimuli can induce seizures in patients with epilepsy and predisposed subjects. Visual stimuli are the most common triggers, provoking seizures through an abnormal response to light or pattern. Sensitive patients may intentionally provoke their seizures through visual stimuli. Self-induction methods are widely described in photo-sensitive patients, while there are only a few reports of those who are pattern-sensitive. We analyzed 73 images of environmental visual triggers collected from 14 pattern-sensitive patients with self-induced seizures. The images were categorized according to their topics: 29 Objects (43%); 19 Patterns (28%); 15 External scenes (22%); 4 TV or computer screens (6%). Six photos were of poor quality and were excluded from analysis. Images were analyzed by an algorithm that calculated the degree to which the Fourier amplitude spectrum differed from that in images from nature. The algorithm has been shown to predict discomfort in healthy observers. The algorithm identified thirty-one images (46%) as “uncomfortable”. There were significant differences between groups of images (ANOVA p = .0036; Chi2 p < .0279), with higher values of difference from nature in the images classified as “Objects” (mean 6,81E+11; SD 6,72E+11; n.17, 59%) and “Pattern” (mean 9,05E+11; SD 6,86E+11; n.14, 74%). During the semi-structured face-to-face interviews, all patients described the visual triggers as ‘uncomfortable’; the appearance of enjoyable visual epileptic symptoms (especially multi-colored hallucinations) transformed uncomfortable images into pleasant stimuli. Patients considered self-induction as the simplest and most effective way to overcome stressful situations, suggesting that self-inducing pattern-sensitive patients often use uncomfortable visual stimuli to trigger their seizures. Among the reasons for the self-inducing behavior, the accidental discovery of pleasurable epileptic symptoms related to these “uncomfortable” visual stimuli should be considered.
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Exposure to urban environments requires more cognitive processing than exposure to nature; an effect that can even be measured analysing gait kinematics whilst people walk towards photographic images. Here, we investigated whether differences in cognitive load between nature and urban scenes are still present when scenes are matched for their liking scores. Participants were exposed to images of nature and urban scenes that had been matched a priori for their liking scores by an independent participant sample (n = 300). Participants (N = 44) were either asked to memorise each image during walking or to rate each image for its visual discomfort after each walk. Irrespective of experimental task, liking score but not environment type predicted gait velocity. Moreover, subjective visual discomfort was predictive of gait velocity. The positive impact of nature described in the literature thus might, at least in part, be due to people’s aesthetic preferences for nature images.
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Uncomfortable images generally have a particular spatial structure, which deviates from a reciprocal relationship between amplitude and spatial frequency (f) in the Fourier domain (1/f). Although flickering patterns with similar temporal structure also appear uncomfortable, the discomfort is affected by not only the amplitude spectrum but also the phase spectrum. Here we examined how discomfort from flicker with differing temporal profiles also varies as a function of the mean light level and luminance contrast of the stimulus. Participants were asked to rate discomfort for a 17° flickering uniform field at different light levels from scotopic to photopic. The flicker waveform was varied with a square wave or random phase spectrum and filtered by modulating the slope of the amplitude spectrum relative to 1/f. At photopic levels, the 1/f square wave flicker appeared most comfortable, whereas the discomfort from the random flicker increased monotonically as the slope of the amplitude spectrum decreased. This special status for the 1/f square wave condition was limited to photopic light levels. At the lower mesopic or scotopic levels, the effect of phase spectrum on the discomfort was diminished, with both phase spectra showing a monotonic change with the slope of the amplitude spectrum. We show that these changes cannot be accounted for by changes in the effective luminance contrast of the stimuli or by the responses from a linear model based on the temporal impulse responses under different light levels. However, discomfort from flicker is robustly correlated with judgments of the perceived naturalness of flicker across different contrasts and mean luminance levels.
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Background Trypophobia is a common condition in which sufferers are averse to images of small holes arranged in clusters. Methods We used photo-plethysmography to examine cardiovascular correlates and near infrared spectroscopy to examine cortical correlates of the phenomenon in order to validate the Trypophobia Questionnaire and explore the several interlinked explanations of the disorder. Results Trypophobic images were found to increase both heart rate and heart rate variability, but only in individuals with high scores on the Trypophobia Questionnaire. Trypophobic images were also found to elicit larger haemodynamic responses in posterior cortical areas, but again only in individuals with high scores. Limitations The results are consistent with a contribution from both parasympathetic and sympathetic systems. Conclusion The data demonstrate the validity of the Trypophobia Questionnaire and show an involvement not only of the autonomic system but cortical mechanisms including cortical hyperexcitability.
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Nowadays, crowded environment and high-speed life pace are likely to bring mental stress and fatigue to citizens. How to apply achievements of the restorative environment into urban planning and environmental design has received more attention in recent years.Earlier research does not provide detailed information about the specific components of the physical environment that support restoration. This study explores which characteristics of the street environment and psychological factors of the street environment have an impact on subjective restoration. The streets were sampled from Shenzhen. Each street was represented by a single photo. The photo was quantified in terms of the different objective street components and also rated on psychological variables related to restoration. The rating on the psychological variables, being away, fascination, coherence, scope, the likelihood of restoration, and preference were provided by people of various ages and occupations. The results show that: (1) The proportion of natural elements have the greatest impact on street restoration benefits and preference and its impact is robust. (2) The two characteristics of street safety and quiet are important to street restoration benefits and preferences. (3)Fascination and Being away have a greater impact on restorative benefits of streets, followed by Coherence, and the Scope of the street has no significant effect on restorative benefits. The study could provide evidence for policy-makers and urban design and planning interventions.
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The brain of migraineurs is hyperexcitable, particularly the occipital cortex, which is probably hypersensitive to light. Photophobia or hypersensitivity to light may be accounted for by an increased excitability of trigeminal, the visual pathways, and the occipital cortex. To study light sensitivity and photophobia by assessing the response to light stimuli with functional magnetic resonance imaging-blood oxygenation level dependent (fMRI-BOLD) of the occipital cortex in migraineurs and in controls. Also, to try to decipher the contribution of the occipital cortex to photophobia and whether the cortical reactivity of migraineurs may be part of a constitutional (defensive) mechanism or represents an acquired (sensitization) phenomenon. Nineteen patients with migraine (7 with aura and 12 without aura) and 19 controls were studied with fMRI-BOLD during 4 increasing light intensities. Eight axial image sections of 0.5 cm that covered the occipital cortex were acquired for each intensity. We measured the extension and the intensity of activation for every light stimuli. Photophobia was estimated according to a 0 to 3 semiquantitative scale of light discomfort. Migraineurs had a significantly higher number of fMRI-activated voxels at low (320.4 for migraineurs [SD = 253.9] and 164.3 for controls [SD = 102.7], P = .027) and medium-low luminance levels (501.2 for migraineurs [SD = 279.5] and 331.1 for controls [SD = 194.3], P = .034) but not at medium-high (579.5 for migraineurs [SD = 201.4] and 510.2 for controls [SD = 239.5], P = .410) and high light stimuli (496.2 for migraineurs [SD = 216.2] and 394.7 for controls [SD = 240], P = .210). No differences were found with respect to the voxel activation intensity (amplitude of the BOLD wave) between migraineurs and controls (8.98 [SD = 2.58] vs 7.99 [SD = 2.57], P = .25; 10.82 [SD = 3.27] vs 9.81 [SD = 3.19], P = .31; 11.90 [SD = 3.18] vs 11.06 [SD = 2.56], P = .62; 11.45 [SD = 2.65] vs 10.25 [SD = 2.22], P = .16). Light discomfort was higher in the group of migraineurs at all the intensities tested, but there was no correlation with the number of activated voxels in the occipital cortex and photophobia. Repetitive light stimuli failed to demonstrate a lack of habituation in migraineurs. Migraineurs during interictal periods showed hyperxcitability of the visual cortex with a wider photoresponsive area, the underlying mechanism probably being dual: constitutional-defensive and acquired-sensitizating.
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The relative efficiency of any particular image-coding scheme should be defined only in relation to the class of images that the code is likely to encounter. To understand the representation of images by the mammalian visual system, it might therefore be useful to consider the statistics of images from the natural environment (i.e., images with trees, rocks, bushes, etc). In this study, various coding schemes are compared in relation to how they represent the information in such natural images. The coefficients of such codes are represented by arrays of mechanisms that respond to local regions of space, spatial frequency, and orientation (Gabor-like transforms). For many classes of image, such codes will not be an efficient means of representing information. However, the results obtained with six natural images suggest that the orientation and the spatial-frequency tuning of mammalian simple cells are well suited for coding the information in such images if the goal of the code is to convert higher-order redundancy (e.g., correlation between the intensities of neighboring pixels) into first-order redundancy (i.e., the response distribution of the coefficients). Such coding produces a relatively high signal-to-noise ratio and permits information to be transmitted with only a subset of the total number of cells. These results support Barlow's theory that the goal of natural vision is to represent the information in the natural environment with minimal redundancy.
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Near infrared spectroscopy (NIRS) has been used to measure concentration changes of cerebral hemoglobin and cytochrome in neonates, children, and adults, to study cerebral oxygenation and hemodynamics. To derive quantitative concentration changes from measurements of light attenuation, the optical path length must be known. This is obtained by multiplying the source/ detector separation by a laboratory measured differential path length factor (DPF) which accounts for the increased distance traveled by light due to scattering. DPF has been measured by time of flight techniques on small populations of adults and postmortem infants. The values for adults are greater than those for newborns, and it is not clear how to interpolate the present data for studies on children. Recent developments in instrumentation using phase resolved spectroscopy techniques have produced a bedside unit which can measure optical path length on any subject. We have developed an intensity modulated optical spectrometer which measures path length at four wavelengths. Two hundred and eighty three subjects from 1 d of age to 50 y were studied. Measurements were made at a fixed frequency of 200 MHz and a source detector separation of 4.5 cm. Results suggest a slowly varying age dependence of DPF, following the relation DPF690 = 5.38 + 0.049A0.877, DPF744 = 5.11 + 0.106A0.723, DPF807 = 4.99 + 0.067A0.814, and DPF832 = 4.67 + 0.062A0.819, where DPF690 is the DPF measured at 690 nm and A is age is expressed in years from full term. There was a wide scatter of values, however, implying that ideally DPF should be measured at the time of each study.
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Migraineurs with visual aura are highly susceptible to illusions and visual distortion and are particularly sensitive to a pattern of regularly spaced parallel lines or stripes. To determine whether the high degree of susceptibility to illusions and visual distortion in migraineurs with aura is associated with hyperneurological activity of the occipital cortex. In order to investigate any relationships among neuronal activity, spatial frequency of square-wave gratings, and self-described visual distortion, we investigated the neuronal and psychophysical responses to square-wave gratings in migraineurs with visual aura and in nonheadache controls. Square-wave gratings provoked various types of visual distortion and illusions and induced a hyperneuronal response in the visual cortex of migraineurs with visual aura, a response that strongly depended upon the stimulus spatial frequency. The hyperneuronal activity of the occipital cortex is consistent with general cortical hyperexcitability in migraine.
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Visual system is a high interest topic in neuroscience research. The new neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), allow us to quickly improve our knowledge on the visual system using non-invasive methods. This work examines the effect of small changes in the intensity of a visual stimulus over the BOLD response in the visual cortex. To perform a detailed analysis of the visual cortex reaction to different intensities of a light source and to verify the ties between the intensity of the visual stimulus and the cortical response. Using fMRI (3 T), we registered BOLD response (area and intensity of the signal change) in 20 photophobic patients and 20 controls while viewing different stimulus intensities from a light source. We found a direct relation between stimulus intensity and occipital response. We show that cortical reactivity is higher in patients with photophobia than normal controls, specially for the lower and medium intensities. fMRI is a valid and robust technique to register consistent and reproducible responses in different groups of subjects. It is useful for the study of normal cortex functioning as well as for clinical use.
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The environments in which we live and the tasks we must perform to survive and reproduce have shaped the design of our perceptual systems through evolution and experience. Therefore, direct measurement of the statistical regularities in natural environments (scenes) has great potential value for advancing our understanding of visual perception. This review begins with a general discussion of the natural scene statistics approach, of the different kinds of statistics that can be measured, and of some existing measurement techniques. This is followed by a summary of the natural scene statistics measured over the past 20 years. Finally, there is a summary of the hypotheses, models, and experiments that have emerged from the analysis of natural scene statistics.
Uncomfortable images produce non-sparse responses in a model of primary visual cortex
  • P B Hibbard
  • L Hare
Hibbard, P. B., & O'Hare, L. (2014). Uncomfortable images produce non-sparse responses in a model of primary visual cortex. Royal Society Open Science, 2, 140535.