In visual perception, an optical illusion is an illusion caused by the visual system and characterized by a visual percept that arguably appears to differ from reality. Illusions come in a wide variety; their categorization is difficult because the underlying cause is often not clear but a classification proposed by Richard Gregory is useful as an orientation. According to that, there are three main classes: physical, physiological, and cognitive illusions, and in each class there are four kinds: Ambiguities, distortions, paradoxes, and fictions. A classical example for a physical distortion would be the apparent bending of a stick half immerged in water; an example for a physiological paradox is the motion aftereffect. An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo, Poggendorff, and Müller-Lyer illusion. Physical illusions are caused by the physical environment, e.g. by the optical properties of water. Physiological illusions arise in the eye or the visual pathway, e.g. from the effects of excessive stimulation of a specific receptor type. Cognitive visual illusions are the result of unconscious inferences and are perhaps those most widely known.
A saccade is a quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction. In contrast, in smooth pursuit movements, the eyes move smoothly instead of in jumps. The phenomenon can be associated with a shift in frequency of an emitted signal or a movement of a body part or device. Controlled cortically by the frontal eye fields (FEF), or subcortically by the superior colliculus, saccades serve as a mechanism for fixation, rapid eye movement, and the fast phase of optokinetic nystagmus. The word appears to have been coined in the 1880s by French ophthalmologist Émile Javal, who used a mirror on one side of a page to observe eye movement in silent reading, and found that it involves a succession of discontinuous individual movements.
Neuroesthetics is a relatively recent sub-discipline of applied aesthetics. Empirical aesthetics takes a scientific approach to the study of aesthetic experience of art, music, or any object that can give rise to aesthetic judgments. Neuroesthetics is a term coined by Semir Zeki in 1999 and received its formal definition in 2002 as the scientific study of the neural bases for the contemplation and creation of a work of art. Neuroesthetics uses neuroscience to explain and understand the aesthetic experiences at the neurological level. The topic attracts scholars from many disciplines including neuroscientists, art historians, artists, art therapists and psychologists.
Vision science is the scientific study of visual perception. Researchers in vision science can be called vision scientists, especially if their research spans some of the science's many disciplines.
Microsaccades are a kind of fixational eye movement. They are small, jerk-like, involuntary eye movements, similar to miniature versions of voluntary saccades. They typically occur during prolonged visual fixation, not only in humans, but also in animals with foveal vision. Microsaccade amplitudes vary from 2 to 120 arcminutes. The first empirical evidence for their existence was provided by Robert Darwin, the father of Charles Darwin.
Troxler's fading, also called Troxler fading or the Troxler effect, is an optical illusion affecting visual perception. When one fixates on a particular point for even a short period of time, an unchanging stimulus away from the fixation point will fade away and disappear. Research suggests that at least some portion of the perceptual phenomena associated with Troxler's fading occurs in the brain.
Geraint Ellis Rees is Vice-Provost of research, innovation & global engagement at University College London (UCL). Previously he served as Dean of the UCL Faculty of Life Sciences, UCL Pro-Provost, Pro-Vice-Provost (AI) and a Professor of Cognitive Neurology at University College London. He is also a Director of UCL Business and a trustee of the Guarantors of Brain.
Fixation or visual fixation is the maintaining of the gaze on a single location. An animal can exhibit visual fixation if it possess a fovea in the anatomy of their eye. The fovea is typically located at the center of the retina and is the point of clearest vision. The species in which fixational eye movement has been verified thus far include humans, primates, cats, rabbits, turtles, salamanders, and owls. Regular eye movement alternates between saccades and visual fixations, the notable exception being in smooth pursuit, controlled by a different neural substrate that appears to have developed for hunting prey. The term "fixation" can either be used to refer to the point in time and space of focus or the act of fixating. Fixation, in the act of fixating, is the point between any two saccades, during which the eyes are relatively stationary and virtually all visual input occurs. In the absence of retinal jitter, a laboratory condition known as retinal stabilization, perceptions tend to rapidly fade away. To maintain visibility, the nervous system carries out a procedure called fixational eye movement, which continuously stimulates neurons in the early visual areas of the brain responding to transient stimuli. There are three categories of fixational eye movement: microsaccades, ocular drifts, and ocular microtremor. At small amplitudes the boundaries between categories become unclear, particularly between drift and tremor.
The neural correlates of consciousness (NCC) refer to the relationships between mental states and neural states and constitute the minimal set of neuronal events and mechanisms sufficient for a specific conscious percept. Neuroscientists use empirical approaches to discover neural correlates of subjective phenomena; that is, neural changes which necessarily and regularly correlate with a specific experience. The set should be minimal because, under the materialist assumption that the brain is sufficient to give rise to any given conscious experience, the question is which of its components are necessary to produce it.
Visual perception is the ability to interpret the surrounding environment through photopic vision, color vision, scotopic vision, and mesopic vision, using light in the visible spectrum reflected by objects in the environment. This is different from visual acuity, which refers to how clearly a person sees. A person can have problems with visual perceptual processing even if they have 20/20 vision.
The Troland Research Awards are an annual prize given by the United States National Academy of Sciences to two researchers in recognition of psychological research on the relationship between consciousness and the physical world. The areas where these award funds are to be spent include but are not limited to areas of experimental psychology, the topics of sensation, perception, motivation, emotion, learning, memory, cognition, language, and action. The award preference is given to experimental work with a quantitative approach or experimental research seeking physiological explanations.
Jocelyn Faubert is a psychophysicist best known for his work in the fields of visual perception, vision of the elderly, and neuropsychology. Professor Faubert holds the NSERC-Essilor Industrial Research Chair in Visual Perception and Presbyopia. He is the director of the Laboratory of Psychophysics and Visual Perception at the University of Montreal. Professor Faubert has also been involved in the award-winning transfer of research and developments from the laboratory into the commercial domain. He is a co-founder and member of the Board of Directors of CogniSens Inc.
Chronostasis is a type of temporal illusion in which the first impression following the introduction of a new event or task-demand to the brain can appear to be extended in time. For example, chronostasis temporarily occurs when fixating on a target stimulus, immediately following a saccade. This elicits an overestimation in the temporal duration for which that target stimulus was perceived. This effect can extend apparent durations by up to half a second and is consistent with the idea that the visual system models events prior to perception.
Melvyn Alan Goodale FRSC, FRS is a Canadian neuroscientist. He was the founding Director of the Brain and Mind Institute at the University of Western Ontario where he holds the Canada Research Chair in Visual Neuroscience. He holds appointments in the Departments of Psychology, Physiology & Pharmacology, and Ophthalmology at Western. Goodale's research focuses on the neural substrates of visual perception and visuomotor control.
The Best Illusion of the Year Contest is an annual recognition of the world's illusion creators awarded by the Neural Correlate Society. The contest was created in 2005 by professors Susana Martinez-Conde and Stephen Macknik as part of the European conference on Visual Perception in La Coruna, Spain. It has since transitioned to an online contest where everyone in the world is invited to submit illusions and vote for the winner.
The SUNY Downstate Health Sciences University is a public medical school in New York City and one of the three components of SUNY Downstate Health Sciences University: University Hospital at Long Island College Hospital, SUNY Downstate at Bay Ridge, and University Hospital of Brooklyn in East Flatbush, whose staffing is provided by SUNY Downstate College of Medicine.
Stephen Louis Macknik is an American neuroscientist and science writer. He is a Professor of Ophthalmology, Neurology, and Physiology & Pharmacology at the State University of New York, Downstate Medical Center, where he directs the Laboratory of Translational Neuroscience. He directed laboratories previously at the Barrow Neurological Institute and University College London. He is best known for his studies on illusions, consciousness, attentional misdirection in stage magic, and cerebral blood flow.
Sleights of Mind: What the Neuroscience of Magic Reveals about Our Everyday Deceptions is a 2010 popular science book, written by neuroscientists Stephen Macknik and Susana Martinez-Conde, with science writer Sandra Blakeslee. Working alongside some of the world’s greatest magicians, Macknik and Martinez-Conde studied how conjuring techniques trick the brain. Sleights of Mind considers the greater implications of magic and misdirection for clinical conditions such as autism, and for everyday life situations, including choice and trust in personal and business relationships.
Michael E. Goldberg, also known as Mickey Goldberg, is an American neuroscientist and David Mahoney Professor at Columbia University. He is known for his work on the mechanisms of the mammalian eye in relation to brain activity. He served as president of the Society for Neuroscience from 2009 to 2010.
Researchers study the reactions of animals observing humans performing magic tricks in order to better understand animal cognition. Using these studies, evolutionary psychologists aim to gain insights into the evolution of perception and attention by comparing responses of different species, including humans.
