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Illusions
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. Illusions may occur with any of the human senses, but visual illusions (optical illusions) are the best-known and understood. The emphasis on visual illusions occurs because vision often dominates the other senses. For example, individuals watching a ventriloquist will perceive the voice is coming from the dummy since they are able to see the dummy mouth the words. Some illusions are based on general assumptions the brain makes during perception. These assumptions are made using organizational principles (e.g., Gestalt theory), an individual's capacity for depth perception and motion perception, and perceptual constancy. Other illusions occur because of biological sensory structures within the human body or conditions outside the body within one's physica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sense
A sense is a biological system used by an organism for sensation, the process of gathering information about the world through the detection of stimuli. (For example, in the human body, the brain which is part of the central nervous system receives signals from the senses which continuously receive information from the environment, interprets these signals, and causes the body to respond, either chemically or physically.) Although traditionally five human senses were identified as such (namely sight, smell, touch, taste, and hearing), it is now recognized that there are many more. Senses used by non-human organisms are even greater in variety and number. During sensation, sense organs collect various stimuli (such as a sound or smell) for transduction, meaning transformation into a form that can be understood by the brain. Sensation and perception are fundamental to nearly every aspect of an organism's cognition, behavior and thought. In organisms, a sensory organ co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Illusion
Within visual perception, an optical illusion (also called a visual 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 (where, despite movement, position remains unchanged). An example for a physiological fiction is an afterimage. Three typical cognitive distortions are the Ponzo, Poggendorff, and Müller-Lyer illusion. Physical illusions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphene
A phosphene is the phenomenon of seeing light without light entering the eye. The word ''phosphene'' comes from the Greek words ''phos'' (light) and ''phainein'' (to show). Phosphenes that are induced by movement or sound may be associated with optic neuritis. Phosphenes can be induced by mechanical, electrical, or magnetic stimulation of the retina or visual cortex, or by random firing of cells in the visual system. Phosphenes have also been reported by meditators (called '' nimitta''), people who endure long periods without visual stimulation (the prisoner's cinema), or those who ingest psychedelic drugs. Causes Mechanical stimulation The most common phosphenes are pressure phosphenes, caused by rubbing or applying pressure on or near the closed eyes. They have been known since antiquity, and described by the Greeks. The pressure mechanically stimulates the cells of the retina. Experiences include a darkening of the visual field that moves against the rubbing, a dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perception
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system, which in turn result from physical or chemical stimulation of the sensory system.Goldstein (2009) pp. 5–7 Vision involves light striking the retina of the eye; smell is mediated by odor molecules; and hearing involves pressure waves. Perception is not only the passive receipt of these signals, but it is also shaped by the recipient's learning, memory, expectation, and attention. Gregory, Richard. "Perception" in Gregory, Zangwill (1987) pp. 598–601. Sensory input is a process that transforms this low-level information to higher-level information (e.g., extracts shapes for object recognition). The process that follows connects a person's concepts and expectations (or knowledge), restorative and selective mechanisms (such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fortification Illusions
Scintillating scotoma is a common visual aura that was first described by 19th-century physician Hubert Airy (1838–1903). Originating from the brain, it may precede a migraine headache, but can also occur acephalgically (without headache), also known as visual migraine or migraine aura. It is often confused with retinal migraine, which originates in the eyeball or socket. Signs and symptoms Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the visual field, which prevents vision within the scotoma area. It typically affects both eyes, as it is not a problem specific to one eye. The affected area flickers but is not dark. It then gradually expands outward from the initial spot. Vision remains normal beyond the borders of the expanding scotoma(s), with objects melting into the scotoma area background similarly to the physiological blind spot, which means that objects may be seen better by not looking directl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory
The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it occurs when an odor binds to a receptor within the nasal cavity, transmitting a signal through the olfactory system. Glomeruli aggregate signals from these receptors and transmit them to the olfactory bulb, where the sensory input will start to interact with parts of the brain responsible for smell identification, memory, and emotion. There are many different causes for alteration, lack, or disturbance to a normal sense of smell, and can include damage to the nose or smell receptors, or central problems affecting the brain. Some causes include upper respiratory infections, traumatic brain injury, and neurodegenerative disease. History of study Early scientific study of the sense of smell includes the extensive doctoral disserta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Perception
The study of time perception or chronoception is a field within psychology, cognitive linguistics and neuroscience that refers to the subjective experience, or sense, of time, which is measured by someone's own perception of the duration of the indefinite and unfolding of events. The perceived time interval between two successive events is referred to as perceived duration. Though directly experiencing or understanding another person's perception of time is not possible, perception can be objectively studied and inferred through a number of scientific experiments. Some temporal illusions help to expose the underlying neural mechanisms of time perception. Pioneering work, emphasizing species-specific differences, was conducted by Karl Ernst von Baer. Theories Time perception is typically categorized in three distinct ranges, because different ranges of duration are processed in different areas of the brain: * Sub-second timing or millisecond timing * Interval timing or seconds-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technology Review
''MIT Technology Review'' is a bimonthly magazine wholly owned by the Massachusetts Institute of Technology, and editorially independent of the university. It was founded in 1899 as ''The Technology Review'', and was re-launched without "The" in its name on April 23, 1998 under then publisher R. Bruce Journey. In September 2005, it was changed, under its then editor-in-chief and publisher, Jason Pontin, to a form resembling the historical magazine. Before the 1998 re-launch, the editor stated that "nothing will be left of the old magazine except the name." It was therefore necessary to distinguish between the modern and the historical ''Technology Review''. The historical magazine had been published by the MIT Alumni Association, was more closely aligned with the interests of MIT alumni, and had a more intellectual tone and much smaller public circulation. The magazine, billed from 1998 to 2005 as "MIT's Magazine of Innovation," and from 2005 onwards as simply "published by MIT" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutaneous Rabbit Illusion
The cutaneous rabbit illusion (also known as cutaneous saltation and sometimes the cutaneous rabbit effect or CRE) is a tactile illusion evoked by tapping two or more separate regions of the skin in rapid succession. The illusion is most readily evoked on regions of the body surface that have relatively poor spatial acuity, such as the forearm. A rapid sequence of taps delivered first near the wrist and then near the elbow creates the sensation of sequential taps hopping up the arm from the wrist towards the elbow, although no physical stimulus was applied between the two actual stimulus locations. Similarly, stimuli delivered first near the elbow then near the wrist evoke the illusory perception of taps hopping from elbow towards wrist. The illusion was discovered by Frank Geldard and Carl Sherrick of Princeton University, in the early 1970s, and further characterized by Geldard (1982) and in many subsequent studies. Geldard and Sherrick likened the perception to that of a rabbit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Grill Illusion
The thermal grill illusion is a sensory illusion originally demonstrated in 1896 by the Swedish physician Torsten Thunberg. The illusion is created by an interlaced grill of bars which are warm, e.g. , and cool, e.g. . When someone presses a hand against the grill, they experience the illusion of burning heat. But if the person presses against only a cool bar, only coolness is experienced; if the person presses against only a warm bar, only warmth is experienced. Researchers have used the illusion to demonstrate that burning pain sensation is in fact a mixture of both cold and heat pain and that it is only the inhibition of the cold pain "channel" that reveals the heat component. The illusion is demonstrated by positioning the middle finger in cold water and the ring and index fingers in warm water. Due to shortcomings in the body map - multisensory representation of the body - and this particular sensory input configuration, for some people the brain is tricked into thinking th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phantom Limb
A phantom limb is the sensation that an amputated or missing limb is still attached. Approximately 80 to 100% of individuals with an amputation experience sensations in their amputated limb. However, only a small percentage will experience painful phantom limb sensation. These sensations are relatively common in amputees and usually resolve within two to three years without treatment. Research continues to explore the underlying mechanisms of phantom limb pain (PLP) and effective treatment options. Signs and symptoms Most (80% to 100%) amputees experience a phantom limb, with some of them having non-painful sensations. The amputee may feel very strongly that the phantom limb is still part of the body. People will sometimes feel as if they are gesturing, feel itches, twitch, or even try to pick things up. The missing limb often feels shorter and may feel as if it is in a distorted and painful position. Occasionally, the pain can be made worse by stress, anxiety and weather ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
