The philosophy of perception is concerned with the nature of perceptual experience and the status of perceptual data, in particular how they relate to beliefs about, or knowledge of, the world. Any explicit account of perception requires a commitment to one of a variety of ontological or metaphysical views. Philosophers distinguish internalist accounts, which assume that perceptions of objects, and knowledge or beliefs about them, are aspects of an individual's mind, and externalist accounts, which state that they constitute real aspects of the world external to the individual. The position of naïve realism—the 'everyday' impression of physical objects constituting what is perceived—is to some extent contradicted by the occurrence of perceptual illusions and hallucinations and the relativity of perceptual experience as well as certain insights in science. Realist conceptions include phenomenalism and direct and indirect realism. Anti-realist conceptions include idealism and skepticism. Recent philosophical work have expanded on the philosophical features of perception by going beyond the single paradigm of vision.
An illusion is a distortion of the senses, which can reveal how the mind normally organizes and interprets sensory stimulation. Although illusions distort the human perception of reality, they are generally shared by most people.
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.
In philosophy of perception and epistemology, naïve realism is the idea that the senses provide us with direct awareness of objects as they really are. When referred to as direct realism, naïve realism is often contrasted with indirect realism.
The Moon illusion is an optical illusion which causes the Moon to appear larger near the horizon than it does higher up in the sky. It has been known since ancient times and recorded by various cultures. The explanation of this illusion is still debated.
Multistable perception is a perceptual phenomenon in which an observer experiences an unpredictable sequence of spontaneous subjective changes. While usually associated with visual perception, multistable perception can also be experienced with auditory and olfactory percepts.
The lilac chaser is a visual illusion, also known as the Pac-Man illusion. It consists of 12 lilac, blurred discs arranged in a circle, around a small black, central cross on a grey background. One of the discs disappears briefly, then the next, and the next, and so on, in a clockwise direction. When one stares at the cross for at least 30 seconds, one sees three illusions
- A gap running around the circle of lilac discs;
- A green disc running around the circle of lilac discs in place of the gap; and
- The green disc running around on the grey background, with the lilac discs having disappeared in sequence.
The Harvard Krokodiloes are Harvard University's oldest a cappella singing group, founded in 1946. The group consists of twelve tuxedo-clad undergraduates, and they sing songs from the Great American Songbook and beyond.
George McDonald Church is an American geneticist, molecular engineer, chemist, serial entrepreneur, and pioneer in personal genomics and synthetic biology. He is the Robert Winthrop Professor of Genetics at Harvard Medical School, Professor of Health Sciences and Technology at Harvard University and Massachusetts Institute of Technology, and a founding member of the Wyss Institute for Biologically Inspired Engineering at Harvard University.
Dale Purves is an American neuroscientist. He is Geller Professor of Neurobiology Emeritus in the Duke Institute for Brain Sciences where he remains Research Professor with additional appointments in the department of Psychology and Brain Sciences, and the department of Philosophy at Duke University. He earned a B.A. from Yale University in 1960 and an M.D. from Harvard Medical School in 1964. After further clinical training as a surgical resident at the Massachusetts General Hospital, service as a Peace Corps physician, and postdoctoral training at Harvard and University College London, he was appointed to the faculty at Washington University School of Medicine in 1973. He came to Duke in 1990 as the founding chair of the Department of Neurobiology at Duke Medical Center, and was subsequently Director of Duke's Center for Cognitive Neuroscience (2003-2009) and also served as the Director of the Neuroscience and Behavioral Disorders Program at the Duke-NUS Graduate Medical School in Singapore (2009-2013).
Bruce MacFarlane Hood is a Canadian-born British experimental psychologist and philosopher who specialises in developmental cognitive neuroscience. He is currently based at the University of Bristol and his major research interests include intuitive theories, self identity, essentialism and the cognitive processes behind adult magical thinking.
Dominic D. P. Johnson is an Alistair Buchan Professor of International Relations at St Antony's College, Oxford.
Mark Slouka is an American novelist and essayist who was awarded a Guggenheim Fellowship in 2005. He is a frequent contributor to Harper's Magazine.
Perry Sink Marshall is an American business consultant, and author of books on marketing, business strategy, communications technology, and evolution.
Susana Martinez-Conde is a Spanish-American neuroscientist and science writer. She is a professor of ophthalmology, neurology, physiology, and pharmacology at the SUNY Downstate Medical Center, where she directs the Laboratory of Integrative Neuroscience. She directed laboratories previously at the Barrow Neurological Institute and University College London. Her research bridges perceptual, cognitive, and oculomotor neuroscience. She is best known for her studies on illusions, eye movements and perception, neurological disorders, and attentional misdirection in stage magic.
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.
Motion silencing is an illusion or perceptual phenomenon in which objects that are rapidly changing in a particular salient property seem to cease changing with motion. The illusion was first identified by Jordan Suchow and George Alvarez in the publication of their research on the topic.
The North American Vascular Biology Organization (NAVBO) is a scientific society promoting knowledge exchange in the area of vascular biology. The society organises several international scientific meetings annually which broadly cover the areas of development of blood and lymphatic vasculature, cardiovascular and lymphatic disease, vascular matrix biology and vascular bioengineering.
Anya Christine Hurlbert, also known as Viscountess Ridley, is a British academic who is Professor of Visual Neuroscience and Dean of Advancement at Newcastle University. Her research involves the study of the interaction between colour and light, and how these are interpreted by the human brain.
Roland William Fleming, FRSB is a British and German interdisciplinary researcher specializing in the visual perception of objects and materials. He is the Kurt Koffka Professor of Experimental Psychology at Justus Liebig University of Giessen. and the Executive Director of the Center for Mind, Brain and Behavior of the Universities of Marburg and Giessen. He is also co-Spokesperson for the Research Cluster “The Adaptive Mind”.
