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Illusion
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 physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical 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 perception, 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 illusion, Ponzo, Poggendorff illusion, Poggendorff, an ... [...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] |
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] |
Checker Shadow Illusion
The checker shadow illusion is an optical illusion published by Edward H. Adelson, professor of vision science at MIT in 1995. Description The image depicts a checkerboard with light and dark squares, partly shadowed by another object. The optical illusion is that the area labeled A appears to be a darker color than the area labeled B. However, within the context of the two-dimensional image, they are of identical brightness, ''i.e.'', they would be printed with identical mixtures of ink, or displayed on a screen with pixels of identical color. Related illusions Whilst being one of the most well-known contrast illusions, there are similar effects which cause two regions of identical color to appear differently depending on context: * The Cornsweet illusion creates a boundary between two identically-shaded regions with a discontinuous gradient, resulting in the opposing sides appearing to be different. * The Chubb illusion evokes this effect by surrounding zones with others ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shepard Tone
A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the ''Shepard scale''. This creates the auditory illusion of a tone that seems to continually ascend or descend in pitch, yet which ultimately gets no higher or lower. Construction Each square in Figure 1 indicates a tone, with any set of squares in vertical alignment together making one Shepard tone. The color of each square indicates the loudness of the note, with purple being the quietest and green the loudest. Overlapping notes that play at the same time are exactly one octave apart, and each scale fades in and fades out so that hearing the beginning or end of any given scale is impossible. As a conceptual example of an ascending Shepard scale, the first tone could be an almost inaudible C4 (middle C) and a loud C5 (an octave higher). The next would be a slight ... [...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] |
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] |
Mind
The mind is the set of faculties responsible for all mental phenomena. Often the term is also identified with the phenomena themselves. These faculties include thought, imagination, memory, will, and sensation. They are responsible for various mental phenomena, like perception, pain experience, belief, desire, intention, and emotion. Various overlapping classifications of mental phenomena have been proposed. Important distinctions group them according to whether they are ''sensory'', ''propositional'', ''intentional'', ''conscious'', or ''occurrent''. Minds were traditionally understood as substances but it is more common in the contemporary perspective to conceive them as properties or capacities possessed by humans and higher animals. Various competing definitions of the exact nature of the mind or mentality have been proposed. ''Epistemic definitions'' focus on the privileged epistemic access the subject has to these states. ''Consciousness-based approaches'' give primacy to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Perception
Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions. Depth perception happens primarily due to stereopsis and accommodation of the eye. Depth sensation is the corresponding term for non-human animals, since although it is known that they can sense the distance of an object, it is not known whether they perceive it in the same way that humans do. Depth perception arises from a variety of depth cues. These are typically classified into binocular cues and monocular cues. Binocular cues are based on the receipt of sensory information in three dimensions from both eyes and monocular cues can be observed with just one eye. Binocular cues include retinal disparity, which exploits parallax and vergence. Stereopsis is made possible with binocular vision. Monocular cues include relative size (distant objects subtend smaller visual angles than ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subjective Constancy
Subjective constancy or perceptual constancy is the perception of an object or quality as constant even though our sensation of the object changes. While the physical characteristics of an object may not change, in an attempt to deal with the external world, the human perceptual system has mechanisms that adjust to the stimulus. Visual There are several types of perceptual constancies in visual perception: * ''Size constancy'' is one type of visual subjective constancy. Within a certain range, people's perception of one particular object's size will not change, regardless of changes in distance or the video size change on the retina. The perception of image is still based upon the actual size of the perceptual characteristics. According to optical principles, for the same object, the size of the image on the retina changes as the distance from the object to the observer changes. The greater the distance, the smaller the image is sensed by the retina. When someone is observing an ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallucination
A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combination of 2 conscious states of brain wakefulness and REM sleep. They are distinguishable from several related phenomena, such as dreaming (REM sleep), which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and mental imagery, which does not mimic real perception, and is under voluntary control. Hallucinations also differ from "delusional perceptions", in which a correctly sensed and interpreted stimulus (i.e., a real perception) is given some additional significance. Many hallucinations happen also during sleep paralyses. Hallucinations can occur in any sensory modality—visual, auditory, ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
