Perception

Perception

"Percept", "perceptual", "perceptible" and "imperceptible" redirect here. For the Brian Blade album, see Perceptual (album). For the perceptibility of digital watermarks, see Digital watermarking#Perceptibility. For other uses, see Perception and Percept.
The Necker cube and Rubin vase can be perceived in more than one way.

Perception (from the

  • Theories of Perception Several different aspects on perception
  • Richard L Gregory Theories of Richard. L. Gregory.
  • Comprehensive set of optical illusions, presented by Michael Bach.
  • Optical Illusions Examples of well-known optical illusions.

External links

  • Arnheim, R. (1969). Visual Thinking. Berkeley: University of California Press. ISBN 978-0-520-24226-5.
  • Flanagan, J. R., & Lederman, S. J. (2001). Neurobiology: Feeling bumps and holes. News and Views, Nature, 412(6845):389-91. http://brain.phgy.queensu.ca/flanagan/papers/FlaLed_NAT_01.pdf
  • Gibson, J. J. (1966). The Senses Considered as Perceptual Systems.
  • Gibson, J. J. (1987). The Ecological Approach to Visual Perception. Lawrence Erlbaum Associates. ISBN 0-89859-959-8
  • Robles-De-La-Torre, G. (2006). The Importance of the Sense of Touch in Virtual and Real Environments. IEEE Multimedia,13(3), Special issue on Haptic User Interfaces for Multimedia Systems, pp. 24–30. http://www.roblesdelatorre.com/gabriel/GR-IEEE-MM-2006.pdf

Bibliography

  • Goldstein, E. Bruce (13 February 2009a). Sensation and perception. Cengage Learning.  
  • Gregory, Richard L.; Zangwill, O. L. (1987). The Oxford companion to the mind. Oxford University Press. Retrieved 24 March 2011. 

References

  1. ^ Schacter, Daniel (2011). Psychology. Worth Publishers. 
  2. ^ a b c d e f Goldstein (2009) pp. 5–7
  3. ^ a b c d e Gregory, Richard. "Perception" in Gregory, Zangwill (1987) pp. 598–601.
  4. ^ a b c Bernstein, Douglas A. (5 March 2010). Essentials of Psychology. Cengage Learning. pp. 123–124.  
  5. ^ Gustav Theodor Fechner. Elemente der Psychophysik. Leipzig 1860
  6. ^ a b DeVere, Ronald; Calvert, Marjorie (31 August 2010). Navigating Smell and Taste Disorders. Demos Medical Publishing. pp. 33–37.  
  7. ^ a b Pomerantz, James R. (2003): "Perception: Overview". In: Lynn Nadel (Ed.), Encyclopedia of Cognitive Science, Vol. 3, London: Nature Publishing Group, pp. 527–537
  8. ^ "Sensation and Perception". 
  9. ^ Willis, William D.; Coggeshall, Richard E. (31 January 2004). Sensory Mechanisms of the Spinal Cord: Primary afferent neurons and the spinal dorsal horn. Springer. p. 1.  
  10. ^ a b Alan S. & Gary J. (2011). Perception, Attribution, and Judgment of Others. Organizational Behaviour: Understanding and Managing Life at Work Vol. 7
  11. ^ Leibniz' Monadology
  12. ^ Deleuze and Guattari's What is Philosophy?
  13. ^ Wettlaufer, Alexandra K. (2003). In the mind's eye : the visual impulse in Diderot, Baudelaire and Ruskin, pg. 257. Amsterdam: Rodopi.  
  14. ^ The Secret Advantage Of Being Short by Robert Krulwich. All Things Considered, NPR. 18 May 2009.
  15. ^ Atkinson, Rita L.; Atkinson, Richard C.; Smith, Edward E. (March 1990). Introduction to psychology. Harcourt Brace Jovanovich. pp. 177–183.  
  16. ^ a b c Moore, Brian C. J. (15 October 2009). "Audition". In Goldstein, E. Bruce. Encyclopedia of Perception. Sage. pp. 136–137.  
  17. ^ a b Sonderegger, Theo (16 October 1998). Psychology. John Wiley and Sons. pp. 45–46.  
  18. ^ a b c d Goldstein, E. Bruce (15 October 2009). "Constancy". In E. Bruce Goldstein. Encyclopedia of Perception. Sage. pp. 309–313.  
  19. ^ Roeckelein, Jon E. (2006). Elsevier's dictionary of psychological theories. Elsevier. p. 126.  
  20. ^ Yantis, Steven (2001). Visual perception: essential readings. Psychology Press. p. 7.  
  21. ^ Gray, Peter O. (2006): Psychology, 5th ed., New York: Worth, p. 281. ISBN 978-0-7167-0617-5
  22. ^ Wolfe, Jeremy M.; Kluender, Keith R.; Levi, Dennis M.; Bartoshuk, Linda M.; Herz, Rachel S.; Klatzky, Roberta L.; Lederman, Susan J. (2008). "Gestalt Grouping Principles". Sensation and Perception (2nd ed.). Sinauer Associates. pp. 78, 80.  
  23. ^ Goldstein (2009). pp. 105–107
  24. ^ Banerjee, J. C. (1994). "Gestalt Theory of Perception". Encyclopaedic Dictionary of Psychological Terms. M.D. Publications Pvt. Ltd. pp. 107–108.  
  25. ^ Weiten, Wayne (1998). Psychology: themes and variations (4th ed.). Brooks/Cole Pub. Co. p. 144.  
  26. ^ Corsini, Raymond J. (2002). The dictionary of psychology. Psychology Press. p. 219.  
  27. ^ a b Kushner, Laura H. (2008). Contrast in judgments of mental health. ProQuest. p. 1.  
  28. ^ a b Plous, Scott (1993). The psychology of judgment and decision making. McGraw-Hill. pp. 38–41.  
  29. ^ Moskowitz, Gordon B. (2005). Social cognition: understanding self and others. Guilford Press. p. 421.  
  30. ^ Popper, Arthur N. (30 November 2010). Music Perception. Springer. p. 150.  
  31. ^ Biederlack, J., M. Castelo-Branco, S. Neuenschwander, D.W. Wheeler, W. Singer and D. Nikolić (2006). "Brightness induction: Rate enhancement and neuronal synchronization as complementary codes". Neuron 52: 1073–1083.  
  32. ^ a b Weiten, Wayne (17 December 2008). Psychology: Themes and Variations. Cengage Learning. p. 193.  
  33. ^ a b Coon, Dennis; Mitterer, John O. (29 December 2008). Introduction to Psychology: Gateways to Mind and Behavior. Cengage Learning. pp. 171–172.  
  34. ^ a b c d Hardy, Malcolm; Heyes, Steve (2 December 1999). Beginning Psychology. Oxford University Press. pp. 24–27.  
  35. ^ Block, J. R.; Yuker, Harold E. (1 October 2002). Can You Believe Your Eyes?: Over 250 Illusions and Other Visual Oddities. Robson. pp. 173–174.  
  36. ^ "On the Perception of Incongruity: A Paradigm" by Jerome S. Bruner and Leo Postman. Journal of Personality, 18, pp. 206-223. 1949. Yorku.ca
  37. ^ "Predictive Coding". 
  38. ^ Stone, James V. (2012): "Vision and Brain: How we perceive the world", Cambridge, MIT Press, pp. 155-178.
  39. ^ Gibson, James J. (2002): "A Theory of Direct Visual Perception". In: Alva Noë/Evan Thompson (Eds.), Vision and Mind. Selected Readings in the Philosophy of Perception, Cambridge, MIT Press, pp. 77–89.
  40. ^ Sokolowski, Robert (2008). Phenomenology of the Human Person. New York: Cambridge University Press. pp. 199–200.  
  41. ^ Richards, Robert J. (December 1976). "James Gibson's Passive Theory of Perception: A Rejection of the Doctrine of Specific Nerve Energies". Philosophy and Phenomenological Research 37 (2): 218–233.  
  42. ^ Consciousness in Action, S. L. Hurley, illustrated, Harvard University Press, 2002, 0674007964, pg. 430-432,
  43. ^ Glasersfeld, Ernst von (1995), Radical Constructivism: A Way of Knowing and Learning, London: RoutledgeFalmer; Poerksen, Bernhard (ed.) (2004), The Certainty of Uncertainty: Dialogues Introducing Constructivism, Exeter: Imprint Academic; Wright. Edmond (2005). Narrative, Perception, Language, and Faith, Basingstoke: Palgrave Macmillan.
  44. ^ a b c d e f g h i j k l m n o p q r s Gaulin, Steven J. C. and Donald H. McBurney. Evolutionary Psychology. Prentice Hall. 2003. ISBN 978-0-13-111529-3, Chapter 4, p 81-101.
  45. ^ Bedford,F.L. (2011). The missing sensory modality: the immune system. Perception, 40, 1265-1267 doi:10.1068/p7119 http://www.perceptionweb.com/abstract.cgi?id=p7119
  46. ^ Kolb & Whishaw: Fundamentals of Human Neuropsychology (2003)
  47. ^ "Frequency Range of Human Hearing". The Physics Factbook. 
  48. ^ Watkins, Anthony J.; Raimond, Andrew; Makin, Simon J. (23 March 2010). "Room reflection and constancy in speech-like sounds: Within-band effects". In Enrique A. Lopez-Poveda. The Neurophysiological Bases of Auditory Perception. Springer. p. 440.  
  49. ^ Warren, R.M. (1970). "Restoration of missing speech sounds". Science 167 (3917): 392–393.  
  50. ^ Klatzky RL, Lederman SJ, & Metzger VA (1985). "Identifying objects by touch: An "expert system."". Perception & Psychophysics 37 (37): 299–302.  
  51. ^ Lederman SJ, & Klatzky RL (1987). "Hand movements: A window into haptic object recognition". Cognitive Psychology 19 (3): 342–368.  
  52. ^ Robles-de-la-torre, Gabriel; Hayward, Vincent (2001). "Force can overcome object geometry in the perception of shape through active touch". Nature 412 (6845): 445–448.  
  53. ^ Gibson, J.J. (1966). The senses considered as perceptual systems. Boston: Houghton Mifflin.  
  54. ^ Human biology (Page 201/464) Daniel D. Chiras. Jones & Bartlett Learning, 2005.
  55. ^ a b DeVere, Ronald; Calvert, Marjorie (31 August 2010). Navigating Smell and Taste Disorders. Demos Medical Publishing. pp. 39–40.  
  56. ^ a b c Siegel, George J.; Albers, R. Wayne (2006). Basic neurochemistry: molecular, cellular, and medical aspects. Academic Press. p. 825.  
  57. ^
    • Oh, Mama, What's Up With Umami? foxnews.com, 5 January 2010
    • Umami Dearest: The mysterious fifth taste has dfficially infiltrated the food scene trendcentral.com, 23 February 2010
    • #8 Food Trend for 2010: I Want My Umami foodchannel.com, 6 December 2009
  58. ^ Food texture: measurement and perception (page 3–4/311) Andrew J. Rosenthal. Springer, 1999.
  59. ^ Why do two great tastes sometimes not taste great together? scientificamerican.com. Dr. Tim Jacob, Cardiff University. 22 May 2009.
  60. ^ E. R. Smith, D. M. Mackie (2000). Social Psychology. Psychology Press, 2nd ed., p. 20

Notes

See also

Social perception is the part of perception that allows people to understand the individuals and groups of their social world, and thus an element of social cognition.[60]

Of the social world

Other senses enable perception of body balance, acceleration, gravity, position of body parts, temperature, pain, time, and perception of internal senses such as suffocation, gag reflex, intestinal distension, fullness of rectum and urinary bladder, and sensations felt in the throat and lungs.

Other senses

Taste (or, the more formal term, gustation) is the ability to perceive the taste buds, or gustatory calyculi, concentrated on the upper surface of the tongue.[54] The human tongue has 100 to 150 taste receptor cells on each of its roughly ten thousand taste buds.[55] There are five primary tastes: sweetness, bitterness, sourness, saltiness, and umami. Other tastes can be mimicked by combining these basic tastes.[55][56] The recognition and awareness of umami is a relatively recent development in Western cuisine.[57] The basic tastes contribute only partially to the sensation and flavor of food in the mouth — other factors include smell, detected by the olfactory epithelium of the nose;[6] texture, detected through a variety of mechanoreceptors, muscle nerves, etc.;[56][58] and temperature, detected by thermoreceptors.[56] All basic tastes are classified as either appetitive or aversive, depending upon whether the things they sense are harmful or beneficial.[59]

Taste

Gibson defined the haptic system as "The sensibility of the individual to the world adjacent to his body by use of his body".[53] Gibson and others emphasized the close link between haptic perception and body movement: haptic perception is active exploration. The concept of haptic perception is related to the concept of extended physiological proprioception according to which, when using a tool such as a stick, perceptual experience is transparently transferred to the end of the tool.

Haptic perception is the process of recognizing objects through touch. It involves a combination of somatosensory perception of patterns on the skin surface (e.g., edges, curvature, and texture) and proprioception of hand position and conformation. People can rapidly and accurately identify three-dimensional objects by touch.[50] This involves exploratory procedures, such as moving the fingers over the outer surface of the object or holding the entire object in the hand.[51] Haptic perception relies on the forces experienced during touch.[52]

Touch

The process of perceiving speech begins at the level of the sound within the auditory signal and the process of audition. After processing the initial auditory signal, speech sounds are further processed to extract acoustic cues and phonetic information. This speech information can then be used for higher-level language processes, such as word recognition. Speech perception is not necessarily uni-directional. That is, higher-level language processes connected with morphology, syntax, or semantics may interact with basic speech perception processes to aid in recognition of speech sounds. It may be the case that it is not necessary and maybe even not possible for a listener to recognize phonemes before recognizing higher units, like words for example. In one experiment, Richard M. Warren replaced one phoneme of a word with a cough-like sound. His subjects restored the missing speech sound perceptually without any difficulty and what is more, they were not able to identify accurately which phoneme had been disturbed.[49]

Speech perception is the process by which the sounds of language are heard, interpreted and understood. Research in speech perception seeks to understand how human listeners recognize speech sounds and use this information to understand spoken language. The sound of a word can vary widely according to words around it and the tempo of the speech, as well as the physical characteristics, accent and mood of the speaker. Listeners manage to perceive words across this wide range of different conditions. Another variation is that reverberation can make a large difference in sound between a word spoken from the far side of a room and the same word spoken up close. Experiments have shown that people automatically compensate for this effect when hearing speech.[16][48]

Though the phrase "I owe you" can be heard as three distinct words, a spectrogram reveals no clear boundaries.

Of speech

Sound does not usually come from a single source: in real situations, sounds from multiple sources and directions are superimposed as they arrive at the ears. Hearing involves the computationally complex task of separating out the sources of interest, often estimating their distance and direction as well as identifying them.[16]

Hearing (or audition) is the ability to perceive sound by detecting vibrations. Frequencies capable of being heard by humans are called audio or sonic. The range is typically considered to be between 20 Hz and 20,000 Hz.[47] Frequencies higher than audio are referred to as ultrasonic, while frequencies below audio are referred to as infrasonic. The auditory system includes the outer ears which collect and filter sound waves, the middle ear for transforming the sound pressure (impedance matching), and the inner ear which produces neural signals in response to the sound. By the ascending auditory pathway these are led to the primary auditory cortex within the temporal lobe of the human brain, which is where the auditory information arrives in the cerebral cortex and is further processed there.

Anatomy of the human ear. (The length of the auditory canal is exaggerated in this image)

Of sound

Types

The rod or cone can see, is its receptive field.[46] Receptive fields have been identified for the visual system, auditory system and somatosensory system, so far.

A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic sensation (touch), taste and olfaction (smell). It has been suggested that the immune system is an overlooked sensory modality.[45] In short, senses are transducers from the physical world to the realm of the mind.

Physiology

Theories of visual perception

Evolutionary psychologists claim that perception demonstrates the principle of modularity, with specialized mechanisms handling particular perception tasks.[44] For example, people with damage to a particular part of the brain suffer from the specific defect of not being able to recognize faces (prospagnosia).[44] EP suggests that this indicates a so-called face-reading module.[44]

Scientists who study perception and sensation have long understood the human senses as adaptations.[44] Depth perception consists of processing over half a dozen visual cues, each of which is based on a regularity of the physical world.[44] Vision evolved to respond to the narrow range of electromagnetic energy that is plentiful and that does not pass through objects.[44] Sound waves provide useful information about the sources of and distances to objects, with larger animals making and hearing lower-frequency sounds and smaller animals making and hearing higher-frequency sounds.[44] Taste and smell respond to chemicals in the environment that were significant for fitness in the EEA.[44] The sense of touch is actually many senses, including pressure, heat, cold, tickle, and pain.[44] Pain, while unpleasant, is adaptive.[44] An important adaptation for senses is range shifting, by which the organism becomes temporarily more or less sensitive to sensation.[44] For example, one's eyes automatically adjust to dim or bright ambient light.[44] Sensory abilities of different organisms often coevolve, as is the case with the hearing of echolocating bats and that of the moths that have evolved to respond to the sounds that the bats make.[44]

Building and maintaining sense organs is metabolically expensive, so these organs evolve only when they improve an organism's fitness.[44] More than half the brain is devoted to processing sensory information, and the brain itself consumes roughly one-fourth of one's metabolic resources, so the senses must provide exceptional benefits to fitness.[44] Perception accurately mirrors the world; animals get useful, accurate information through their senses.[44]

Many philosophers, such as Jerry Fodor, write that the purpose of perception is knowledge, but evolutionary psychologists hold that its primary purpose is to guide action.[44] For example, they say, depth perception seems to have evolved not to help us know the distances to other objects but rather to help us move around in space.[44] Evolutionary psychologists say that animals from fiddler crabs to humans use eyesight for collision avoidance, suggesting that vision is basically for directing action, not providing knowledge.[44]

Evolutionary psychology and perception

A mathematical theory of perception-in-action has been devised and investigated in many forms of controlled movement, and has been described in many different species of organism using the General Tau Theory. According to this theory, tau information, or time-to-goal information is the fundamental 'percept' in perception.

[43] Glasersfeld considers an "invariant" as a target to be homed in upon, and a pragmatic necessity to allow an initial measure of understanding to be established prior to the updating that a statement aims to achieve. The invariant does not and need not represent an actuality, and Glasersfeld describes it as extremely unlikely that what is desired or

An ecological understanding of perception derived from Gibson's early work is that of "perception-in-action", the notion that perception is a requisite property of animate action; that without perception, action would be unguided, and without action, perception would serve no purpose. Animate actions require both perception and motion, and perception and movement can be described as "two sides of the same coin, the coin is action". Gibson works from the assumption that singular entities, which he calls "invariants", already exist in the real world and that all that the perception process does is to home in upon them. A view known as constructivism (held by such philosophers as Ernst von Glasersfeld) regards the continual adjustment of perception and action to the external input as precisely what constitutes the "entity", which is therefore far from being invariant.[42]

Perception-in-action

[41].direct perception Specification is a 1:1 mapping of some aspect of the world into a perceptual array; given such a mapping, no enrichment is required and perception is [40]

Perception as direct perception

Theories

Philosopher Andy Clark explains that perception, although it occurs quickly, is not simply a bottom-up process (where minute details are put together to form larger wholes). Instead, our brains use what he calls 'predictive coding'. It starts with very broad constraints and expectations for the state of the world, and as expectations are met, it makes more detailed predictions (errors lead to new predictions, or learning processes). Clark says this research has various implications; not only can there be no completely "unbiased, unfiltered" perception, but this means that there is a great deal of feedback between perception and expectation (perceptual experiences often shape our beliefs, but those perceptions were based on existing beliefs).[37]

One classic psychological experiment showed slower reaction times and less accurate answers when a deck of playing cards reversed the color of the suit symbol for some cards (e.g. red spades and black hearts).[36]

Perceptual set has been demonstrated in many social contexts. People who are primed to think of someone as "warm" are more likely to perceive a variety of positive characteristics in them, than if the word "warm" is replaced by "cold". When someone has a reputation for being funny, an audience is more likely to find them amusing.[34] Individual's perceptual sets reflect their own personality traits. For example, people with an aggressive personality are quicker to correctly identify aggressive words or situations.[34]

Sets can be created by motivation and so can result in people interpreting ambiguous figures so that they see what they want to see.[33] For instance, how someone perceives what unfolds during a sports game can be biased if they strongly support one of the teams.[35] In one experiment, students were allocated to pleasant or unpleasant tasks by a computer. They were told that either a number or a letter would flash on the screen to say whether they were going to taste an orange juice drink or an unpleasant-tasting health drink. In fact, an ambiguous figure was flashed on screen, which could either be read as the letter B or the number 13. When the letters were associated with the pleasant task, subjects were more likely to perceive a letter B, and when letters were associated with the unpleasant task they tended to perceive a number 13.[32]

A perceptual set, also called perceptual expectancy or just set is a predisposition to perceive things in a certain way.[32] It is an example of how perception can be shaped by "top-down" processes such as drives and expectations.[33] Perceptual sets occur in all the different senses.[17] They can be long term, such as a special sensitivity to hearing one's own name in a crowded room, or short term, as in the ease with which hungry people notice the smell of food.[34] A simple demonstration of the effect involved very brief presentations of non-words such as "sael". Subjects who were told to expect words about animals read it as "seal", but others who were expecting boat-related words read it as "sail".[34]

Effect of motivation and expectation

With experience, organisms can learn to make finer perceptual distinctions, and learn new kinds of categorization. Wine-tasting, the reading of X-ray images and music appreciation are applications of this process in the human sphere. Research has focused on the relation of this to other kinds of learning, and whether it takes place in peripheral sensory systems or in the brain's processing of sense information.

Effect of experience

The contrast effect was noted by the 17th Century philosopher John Locke, who observed that lukewarm water can feel hot or cold, depending on whether the hand touching it was previously in hot or cold water.[27] In the early 20th Century, Wilhelm Wundt identified contrast as a fundamental principle of perception, and since then the effect has been confirmed in many different areas.[27] These effects shape not only visual qualities like color and brightness, but other kinds of perception, including how heavy an object feels.[28] One experiment found that thinking of the name "Hitler" led to subjects rating a person as more hostile.[29] Whether a piece of music is perceived as good or bad can depend on whether the music heard before it was pleasant or unpleasant.[30] For the effect to work, the objects being compared need to be similar to each other: a television reporter can seem smaller when interviewing a tall basketball player, but not when standing next to a tall building.[28] In the brain, contrast exerts effects on both neuronal firing rates and neuronal synchrony.[31]

A common finding across many different kinds of perception is that the perceived qualities of an object can be affected by the qualities of context. If one object is extreme on some dimension, then neighboring objects are perceived as further away from that extreme. "Simultaneous contrast effect" is the term used when stimuli are presented at the same time, whereas "successive contrast" applies when stimuli are presented one after another.[26]

Contrast effects

[25] Later research has identified additional grouping principles.[24][23][22][21]) are a set of principles in Gestalt laws of grouping (or principles of grouping The

Law of Closure. The human brain tends to perceive complete shapes even if those forms are incomplete.

Grouping

Perceptual constancy is the ability of perceptual systems to recognise the same object from widely varying sensory inputs.[4][15] For example, individual people can be recognised from views, such as frontal and profile, which form very different shapes on the retina. A coin looked at face-on makes a circular image on the retina, but when held at angle it makes an elliptical image.[16] In normal perception these are recognised as a single three-dimensional object. Without this correction process, an animal approaching from the distance would appear to gain in size.[17][18] One kind of perceptual constancy is color constancy: for example, a white piece of paper can be recognised as such under different colors and intensities of light.[18] Another example is roughness constancy: when a hand is drawn quickly across a surface, the touch nerves are stimulated more intensely. The brain compensates for this, so the speed of contact does not affect the perceived roughness.[18] Other constancies include melody, odor, brightness and words.[19] These constancies are not always total, but the variation in the percept is much less than the variation in the physical stimulus.[18] The perceptual systems of the brain achieve perceptual constancy in a variety of ways, each specialized for the kind of information being processed.[20]

Constancy

Features

Perception is one of the oldest fields in psychology. The oldest quantitative laws in psychology are Weber's law-which states that the smallest noticeable difference in stimulus intensity is proportional to the intensity of the reference-and Fechner's law which quantifies the relationship between the intensity of the physical stimulus and its perceptual counterpart (for example, testing how much darker a computer screen can get before the viewer actually notices). The study of perception gave rise to the Gestalt school of psychology, with its emphasis on holistic approach.

There is also evidence that the brain in some ways operates on a slight "delay", to allow nerve impulses from distant parts of the body to be integrated into simultaneous signals.[14]

This confusing ambiguity of perception is exploited in human technologies such as camouflage, and also in biological mimicry, for example by European Peacock butterflies, whose wings bear eye markings that birds respond to as though they were the eyes of a dangerous predator.

In the case of visual perception, some people can actually see the percept shift in their mind's eye.[13] Others, who are not picture thinkers, may not necessarily perceive the 'shape-shifting' as their world changes. The 'esemplastic' nature has been shown by experiment: an ambiguous image has multiple interpretations on the perceptual level.

Reality

Stimuli are not necessarily translated into a percept and rarely does a single stimulus translate into a percept. An ambiguous stimulus may be translated into multiple percepts, experienced randomly, one at a time, in what is called "multistable perception". And the same stimuli, or absence of them, may result in different percepts depending on subject’s culture and previous experiences. Ambiguous figures demonstrate that a single stimulus can result in more than one percept; for example the Rubin vase which can be interpreted either as a vase or as two faces. The percept can bind sensations from multiple senses into a whole. A picture of a talking person on a television screen, for example, is bound to the sound of speech from speakers to form a percept of a talking person. "Percept" is also a term used by Leibniz,[11] Bergson, Deleuze and Guattari[12] to define perception independent from perceivers.

  1. The Perceiver, the person who becomes aware about something and comes to a final understanding. There are 3 factors that can influence his or her perceptions: experience, motivational state and finally emotional state. In different motivational or emotional states, the perceiver will react to or perceive something in different ways. Also in different situations he or she might employ a "perceptual defence" where they tend to "see what they want to see".
  2. The Target. This is the person who is being perceived or judged. "Ambiguity or lack of information about a target leads to a greater need for interpretation and addition."
  3. The Situation also greatly influences perceptions because different situations may call for additional information about the target.

According to Alan Saks and Gary Johns, there are three components to perception.[10]

  1. When we encounter an unfamiliar target we are open to different informational cues and want to learn more about the target.
  2. In the second step we try to collect more information about the target. Gradually, we encounter some familiar cues which help us categorize the target.
  3. At this stage, the cues become less open and selective. We try to search for more cues that confirm the categorization of the target. We also actively ignore and even distort cues that violate our initial perceptions. Our perception becomes more selective and we finally paint a consistent picture of the target.

Psychologist Jerome Bruner has developed a model of perception. According to him people go through the following process to form opinions:[10]

An example would be a person looking at a shoe. The shoe itself is the distal stimulus. When light from the shoe enters a person's eye and stimulates their retina, that stimulation is the proximal stimulus.[8] The image of the shoe reconstructed by the brain of the person is the percept. Another example would be a telephone ringing. The ringing of the telephone is the distal stimulus. The sound stimulating a person's auditory receptors is the proximal stimulus, and the brain's interpretation of this as the ringing of a telephone is the percept. The different kinds of sensation such as warmth, sound, and taste are called "sensory modalities".[7][9]

The process of perception begins with an object in the real world, termed the distal stimulus or distal object.[2] By means of light, sound or another physical process, the object stimulates the body's sensory organs. These sensory organs transform the input energy into neural activity—a process called transduction.[2][7] This raw pattern of neural activity is called the proximal stimulus.[2] These neural signals are transmitted to the brain and processed.[2] The resulting mental re-creation of the distal stimulus is the percept. Perception is sometimes described as the process of constructing mental representations of distal stimuli using the information available in proximal stimuli.

Process and terminology

Contents

  • Process and terminology 1
  • Reality 2
  • Features 3
    • Constancy 3.1
    • Grouping 3.2
    • Contrast effects 3.3
  • Effect of experience 4
  • Effect of motivation and expectation 5
  • Theories 6
    • Perception as direct perception 6.1
    • Perception-in-action 6.2
    • Evolutionary psychology and perception 6.3
    • Theories of visual perception 6.4
  • Physiology 7
  • Types 8
    • Of sound 8.1
      • Of speech 8.1.1
    • Touch 8.2
    • Taste 8.3
    • Other senses 8.4
    • Of the social world 8.5
  • See also 9
  • Notes 10
  • References 11
  • Bibliography 12
  • External links 13

The perceptual systems of the brain enable individuals to see the world around them as stable, even though the sensory information is typically incomplete and rapidly varying. Human and animal brains are structured in a modular way, with different areas processing different kinds of sensory information. Some of these modules take the form of sensory maps, mapping some aspect of the world across part of the brain's surface. These different modules are interconnected and influence each other. For instance, taste is strongly influenced by smell.[6]

Although the senses were traditionally viewed as passive receptors, the study of illusions and ambiguous images has demonstrated that the brain's perceptual systems actively and pre-consciously attempt to make sense of their input.[3] There is still active debate about the extent to which perception is an active process of hypothesis testing, analogous to science, or whether realistic sensory information is rich enough to make this process unnecessary.[3]

Since the rise of experimental psychology in the 19th Century, psychology's understanding of perception has progressed by combining a variety of techniques.[3] Psychophysics quantitatively describes the relationships between the physical qualities of the sensory input and perception.[5] Sensory neuroscience studies the brain mechanisms underlying perception. Perceptual systems can also be studied computationally, in terms of the information they process. Perceptual issues in philosophy include the extent to which sensory qualities such as sound, smell or color exist in objective reality rather than in the mind of the perceiver.[3]

[2]) that influence perception. Perception depends on complex functions of the nervous system, but subjectively seems mostly effortless because this processing happens outside conscious awareness.attention The "bottom-up" processing transforms low-level information to higher-level information (e.g., extracts shapes for object recognition). The "top-down" processing refers to a person's concept and expectations (knowledge), and selective mechanisms ([4] Perception involves these "top-down" effects as well as the "bottom-up" process of processing sensory input.[4][3].attention, and expectation, memory, learning. Perception is not the passive receipt of these signals, but is shaped by pressure waves, and hearing involves molecules of the eye, smell is mediated by odor retina striking the light For example, vision involves [2]