Fractal Fluency: Processing of Fractal Stimuli Across Sight, Sound, and Touch.

People are continually exposed to the rich complexity generated by the repetition of fractal patterns at different size scales. Fractals are prevalent in natural scenery and also in patterns generated by artists and mathematicians. In this chapter, we will investigate the powerful significance of fractals for the human senses.

Nature in motion: The tuning of the visual system to the spatiotemporal properties of natural scenes.

Natural scenes contain several statistical regularities despite their superficially diverse appearances (e.g., mountains, rainforests, deserts).

Aesthetics and Psychological Effects of Fractal Based Design.

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.

Nice and slow: Measuring sensitivity and visual preference toward naturalistic stimuli varying in their amplitude spectra in space and time.

The 1/f amplitude spectrum is a statistical property of natural scenes characterising a specific distribution of spatial and temporal frequencies and their associated luminance intensities. This property has been studied extensively in the spatial domain whereby sensitivity and visual preference overlap and peak for slopes within the natural range (α ≈ 1), but remains relatively less studied in the temporal domain. Here, we used a 4AFC task to measure sensitivity and a 2AFC task to measure visual preference and across a wide range of spatial (α = 0.

Visual adaptation to natural scene statistics and visual preference.

The amplitude of Fourier spectra for natural scenes falls with spatial frequency (f) and is described by the equation, 1/f, where exponent α corresponds to the slope of the spectral drop-off. For natural scenes α takes on intermediate values ~1.25, reflecting their scale invariance.

Viewing Art in Different Contexts.

While aesthetic experiences are not limited to any particular context, their sensorial, cognitive and behavioral properties can be profoundly affected by the circumstances in which they occur. Given the ubiquitous nature of contextual effects in nearly all aspects of behavior, investigations aimed at delineating the context-dependent and context-independent aspects of aesthetic experience and engagement with aesthetic objects in a diverse range of settings are important in empirical aesthetics. Here, we analyze the viewing behavior of visitors ( = 19) freely viewing 15 paintings in the 20th-century Australian collection room at the Art Gallery of New South Wales.

Preference for Fractal-Scaling Properties Across Synthetic Noise Images and Artworks.

A large number of studies support the notion that synthetic images within a certain intermediate fractal-scaling range possess an intrinsic esthetic value. Interestingly, the fractal-scaling properties that define this intermediate range have also been found to characterize a vast collection of representational, abstract, and graphic art. While some have argued that these statistic properties only serve to maximize the visibility of the artworks' spatial structure, others argue that they are intrinsically tied to the artworks' esthetic appeal.

The tuning of human visual cortex to variations in the 1/f amplitude spectra and fractal properties of synthetic noise images.

Natural scenes share a consistent distribution of energy across spatial frequencies (SF) known as the 1/f amplitude spectrum (α≈0.8-1.5, mean 1.

Do sudden onsets need to be perceived as new objects to capture attention? The interplay between sensory transients and display configuration.

Yantis and Jonides (1984) and Jonides and Yantis (1988) reported robust involuntary attentional capture by sudden-onsets, the origin of which has been debated. Prominent accounts have highlighted aspects that include the "new object" status of a sudden-onset (Yantis & Hillstrom, 1994) and the substantial luminance changes accompanying their appearance (Gellatly, Cole & Blurton, 1999; Franconeri, Hollingworth & Simons, 2005), including relative differences in the amount of sensory change between target and nontarget items (Pinto, Olivers & Theeuwes, 2008). In this research we dissociate the amount of sensory change accompanying sudden onsets from the extent to which they appear as newly created objects in search displays.

Taxonomy of Individual Variations in Aesthetic Responses to Fractal Patterns.

In two experiments, we investigate group and individual preferences in a range of different types of patterns with varying fractal-like scaling characteristics. In Experiment 1, we used 1/f filtered grayscale images as well as their thresholded (black and white) and edges only counterparts. Separate groups of observers viewed different types of images varying in slope of their amplitude spectra.

Created unequal: Temporal dynamics of modal and amodal boundary interpolation.

In this study we manipulate the distribution of contrast polarity reversals in inducing configurations to create novel variants of modal and amodal completion. The novel variants, better equated in their geometric and photometric characteristics offer a superior way to probe similarities and differences in the temporal dynamics that underlie different forms of perceptual completion. We use dot localisation to directly compare the spatial characteristics of modally and amodally interpolated contours at presentation durations ranging from 120 to 300ms and find robust differences in the spatiotemporal formation of modally and amodally completed boundaries.

Beauty and the beholder: the role of visual sensitivity in visual preference.

For centuries, the essence of aesthetic experience has remained one of the most intriguing mysteries for philosophers, artists, art historians and scientists alike. Recently, views emphasizing the link between aesthetics, perception and brain function have become increasingly prevalent (Ramachandran and Hirstein, 1999; Zeki, 1999; Livingstone, 2002; Ishizu and Zeki, 2013). The link between art and the fractal-like structure of natural images has also been highlighted (Spehar et al.

Perceptual organization, visual attention, and objecthood.

We have previously demonstrated that the mere organization of some elements in the visual field into an object attracts attention automatically. Here, we explored three different aspects of this automatic attentional capture: (a) Does the attentional capture by an object involve a spatial component? (b) Which Gestalt organization factors suffice for an object to capture attention? (c) Does the strength of organization affect the object's ability to capture attention? Participants viewed multi-elements displays and either identified the color of one element or responded to a Vernier target. On some trials, a subset of the elements grouped by Gestalt factors into an object that was irrelevant to the task and not predictive of the target.

[Chronic wound in waiting-room].

Chronic wounds are wounds that in addition to standard methods of treatment do not heal within 6-8 weeks, depending on their localization and etiology. Wound healing is affected by a number of factors: physical, psychosocial, relationship to the patient's disease, the condition of the wound itself, as well as the experience and knowledge of medical personnel and financial resources of the institution. Treating chronic wounds begins taking adequate history.

[Plausible solution to prevent major amputation in diabetic foot patients].

Diabetes mellitus is one of the leading public health problems in the world. Complications of diabetes mellitus include cardiovascular diseases, retinopathy, neuropathy and diabetic foot, which can in turn lead to lower extremity amputations. This is the main cause of mortality and the biggest expenditure for health system.

Temporal dynamics of spatial frequency processing in infants.

The current study examined the temporal dynamics of coarse and fine spatial information processing in 7- to 8-month-old infants. The ability to discriminate between spatially filtered images was assessed by measuring infants' spontaneous preference for a changing over no-changing image sequences. In Experiments 1 and 2, we found that infants were able to discriminate between low spatial frequency (LSF) image sequences at shorter durations (150 ms) than was the case with high spatial frequency (HSF) images (300 ms).

Anomalous motion illusion contributes to visual preference.

This study investigated the relationship between the magnitude of illusory motion in the variants of the "Rotating Snakes" pattern and the visual preference among such patterns. In Experiment 1 we manipulated the outer contour and the internal geometrical structure of the figure to test for corresponding modulations in the perceived illusion magnitude. The strength of illusory motion was estimated by the method of adjustment where the speed of a standard moving figure was matched to the speed of the perceived illusory motion in test figures.

When do luminance changes capture attention?

In two experiments, we examined the ability of task-irrelevant changes in luminance to capture attention in an irrelevant singleton search. By using uniform increment and decrement arrays, we were able to create changes of the same absolute magnitude, but resulting in a singleton with either higher or lower contrast magnitude, relative to other elements in the search array. A condition where a singleton changed contrast polarity without a concomitant change in the overall contrast magnitude was also included.

Perception of Mooney faces by young infants: the role of local feature visibility, contrast polarity, and motion.

We examined the ability of young infants (3- and 4-month-olds) to detect faces in the two-tone images often referred to as Mooney faces. In Experiment 1, this performance was examined in conditions of high and low visibility of local features and with either the presence or absence of the outer head contour. We found that regardless of the presence of the outer head contour, infants preferred upright over inverted two-tone face images only when local features were highly visible (Experiment 1a).

Perceptual and Physiological Responses to Jackson Pollock's Fractals.

Fractals have been very successful in quantifying the visual complexity exhibited by many natural patterns, and have captured the imagination of scientists and artists alike. Our research has shown that the poured patterns of the American abstract painter Jackson Pollock are also fractal. This discovery raises an intriguing possibility - are the visual characteristics of fractals responsible for the long-term appeal of Pollock's work? To address this question, we have conducted 10 years of scientific investigation of human response to fractals and here we present, for the first time, a review of this research that examines the inter-relationship between the various results.

Differential effect of contrast polarity reversals in closed squares and open L-junctions.

Scene segmentation depends on interaction between geometrical and photometric factors. It has been shown that reversals in contrast polarity at points of highest orientation discontinuity along closed contours significantly impair shape discrimination performance, while changes in contrast polarity at straight(er) contour segments do not have such deleterious effects (Spehar, 2002). Here we employ (semi) high resolution fMRI (1.

Effects of bioreactive acrolein from automotive exhaust gases on human cells in vitro.

Acrolein is a toxic unsaturated aldehyde and widespread environmental pollutant produced during lipid peroxidation and also by burning of tobacco or liquid fuels. Inhalation or dermal exposure to acrolein could be toxic to organisms. This very reactive aldehyde has a strong affinity for binding to proteins thus forming pathogenic protein-adducts.

Modeling magnification and anisotropy in the primate foveal confluence.

A basic organizational principle of the primate visual system is that it maps the visual environment repeatedly and retinotopically onto cortex. Simple algebraic models can be used to describe the projection from visual space to cortical space not only for V1, but also for the complex of areas V1, V2 and V3. Typically a conformal (angle-preserving) projection ensuring local isotropy is regarded as ideal and primate visual cortex is often regarded as an approximation of this ideal.

Temporal whitening: transient noise perceptually equalizes the 1/f temporal amplitude spectrum.

Naturally occurring luminance distributions are approximately 1/f in their spatial and temporal amplitude spectra. By systematically varying the spatio-temporal profile of broadband noise stimuli, we demonstrate that humans invariably overestimate the proportion of high spatial and temporal frequency energy. Critically, we find that that the strength of this bias is of a magnitude that predicts a perceptually equalized response to the spatio-temporal fall off in the natural amplitude spectrum.

Temporal structure of chromatic channels revealed through masking.

The human color and luminance-driven systems appear to be mediated by mechanisms with distinct spatio-temporal tuning properties, with the iso-luminant color-driven system comparatively less sensitive to high rates of temporal modulation. While color and luminance defined speed and rate discrimination studies indicate perceptual access to the outputs of multiple, overlapping temporal frequency-selective mechanisms (channels), a detailed functional characterization of their response is currently restricted to the luminance-driven domain. Threshold elevations for 1- and 10-Hz targets were measured as a function of the temporal frequency of a spatio-temporally overlaid masking stimulus (1-30 Hz).