Cognitive Psych Reviewer 2.pdf

Perception is the set of processes by which we The dorsal pathway is also called the where recognize, organize, and make sense of the pathway and is responsible for processing location sensations we receive from environmental stimuli. and motion information James Gibs...

Perception is the set of processes by which we The dorsal pathway is also called the where recognize, organize, and make sense of the pathway and is responsible for processing location sensations we receive from environmental stimuli. and motion information James Gibson (1966, 1979) provided a useful The ventral pathway is called the what pathway framework for studying perception in his influential because it is mainly responsible for processing the work. He introduced the concepts of distal color, shape, and identity of visual stimuli (external) object, informational medium, proximal This is the what–where hypothesis. Most of the stimulation, and perceptual object. research in this area has been carried out with The distal (far) object is the object in the monkeys external world (e.g., a falling tree). A tree falling The what–how hypothesis is an alternative creates a pattern on an informational medium. interpretation of the visual pathways (Goodale, 2011; Goodale & Milner, 2004; Goodale &  sensory adaptation, receptor cells adapt to Westwood, 2004). This hypothesis suggests the constant stimulation by not firing until two pathways refer not to what things are and to there is a change in stimulation where they are, but rather to what they are and to  a mental percept—a mental representation how they function. of a stimulus that is perceived Light is electromagnetic radiation that can be Bottom-up theories describe approaches in described in terms of wavelength. which perception starts with the stimuli whose appearance you take in through your eye. Vision begins when light passes through the protective covering of the eye The four main bottom-up theories of form and pattern perception are direct perception, template  Cornea- is a clear dome that protects the theories, feature theories, and recognition-by- eye. components theory.  Llight then passes through the pupil, the opening in the center of the iris.  Gibson’s theory of direct perception, the  It continues through the crystalline lens information in our sensory receptors, and the vitreous humor. The vitreous including the sensory context, is all we need humor is a gel-like substance that makes up to perceive anything also called ecological the majority of the eye. perception.  retina the light focuses on the where electromagnetic light energy is  Templates are highly detailed models for transduced—that is, converted—into neural patterns we might recognize. We recognize electrochemical impulses (Blake, 2000). a pattern by comparing it with our set of templates.Template matching theories  Vision is most acute in the fovea,-which is a belong to the group of chunk-based small, thin region of the retina, the size of theories; these theories suggest that the head of a pin. expertise is attained by acquiring chunks of  The retina contains the photoreceptors, knowledge in long-term memory that can which convert light energy into later be accessed for fast recognition. electrochemical energy that is transmitted  Feature-matching theories. we attempt to by neurons to the brain. There are two match features of a pattern to features kinds of photoreceptors—rods and cones. stored in memory, rather than to match a  rods are long and thin photoreceptors. whole pattern to a template or a prototype  cones are short and thick photoreceptors (Stankiewicz, 2003). and allow for the perception of color.  The Pandemonium Model One such  The axons of the ganglion cells in the eye feature-matching model has been called collectively form the optic nerve for that Pandemonium (“pandemonium” refers to a eye. The optic nerves of the two eyes join at noisy, chaotic place and hell). Conceived by the base of the brain to form the optic Oliver Selfridge, there are four kinds of chiasma demons: image demons, feature demons, cognitive demons, and decision demons. shows this model.  1. The “image demons” receive a retinal perception because it states that higher- image and pass it on to order thinking plays an important role in 2. “feature demons.” Each feature demon perception. calls out when matches are made The percepts are based on the following: between the stimulus and the given feature. These matches are yelled out at  what we sense (the sensory data) demons at the next level of the  what we know (knowledge stored in hierarchy, memory) 3. the “cognitive (thinking) demons.” The  what we can infer (using high-level cognitive demons in turn shout out cognitive processes) possible patterns stored in memory that conform to one or more of the features noticed by the feature demons Context effects are the influences of the 4. A “decision demon” listens to the surrounding environment on perception. pandemonium of the cognitive demons. It decides on what has been seen, based Perhaps even more striking is a context effect on which cognitive demon is shouting. known as the configural-superiority effect (Bar, 2004; Pomerantz, 1981, 2003), by which objects presented in certain configurations are easier to Gnostic units or “grandmother cells” Neurons recognize than the objects presented in isolation, that can recognize a complex object because even if the objects in the configurations are more they imply that there is a neuron that is capable complex than those in isolation. of recognizing your grandmother. Object-superiority effect, in which a target line  Recognition-by-Components Theory How that forms a part of a drawing of a 3-D object is do we form stable 3-D mental identified more accurately than a target that forms representations of objects? The a part of a disconnected 2-D pattern recognition-by-components theory explains it, using simple geometric shapes Word-superiority effect indicates that when people are presented with strings of letters, it is  Seeing with the Help of Geons Irving easier for them to identify a single letter if the Biederman (1987) suggested that we string makes sense and forms a word instead of recognize 3-D objects by manipulating being just a nonsense sequel of letters simple geometric shapes called geons (for geometrical ions). We quickly recognize Perception of Objects and Forms objects by observing the edges of them and Viewer-Centered versus Object-Centered then decomposing the objects into geons. Perception The geons also can be recomposed into alternative arrangements. Viewer-centered representation, is that the individual stores the way the object looks to him or her. Thus, what matters is the appearance of the Top-down theories, according to which object to the viewer perception is driven by high-level cognitive Object-centered representation, is that the processes, existing knowledge, and the prior individual stores a representation of the object, expectations that influence perception independent of its appearance to the viewer. In this case, the shape of the object will stay stable  In constructive perception, the perceiver across different orientations builds (constructs) a cognitive understanding (perception) of a stimulus. Landmark-centered representation, information is The concepts of the perceiver and his or her characterized by its relation to a well-known or cognitive processes influence what he or prominent item. Imagine visiting a new city. Each she sees. According to this theory, day you leave your hotel and go on short trips. perception includes not merely a low-level set of cognitive processes but actually a The Perception of Groups—Gestalt Laws sophisticatedset of processes that interact This viewpoint also is known as intelligent The Gestalt approach to form perception that was developed in Germany in the early twentieth century is particularly useful for understanding how we perceive groups of objects or even parts of objects to form integral wholes Overarching law of the Gestalt approach is the Law of Prägnanz. We tend to perceive any given visual array in a way that most simply organizes the different elements into a stable and coherent form Other Gestalt principles include figure-ground perception, proximity, similarity, continuity, closure, and symmetry  The second system (configurational system) specializes in recognizing Principle of symmetry larger configurations, not analyzing Symmetry requires that features appear to parts of objects or the construction have balanced proportions around a central of the objects. The feature analysis axis or a central point. system can also be used in face recognition. Suppose you see Recognizing Patterns and Faces someone whose face looks vaguely familiar, but you are not sure who it Two Different Pattern Recognition Systems is. You start analyzing features and Humans have two systems for recognizing then realize it is a friend you have patterns, according to Martha Farah (Farah, not seen for 10 years. 1992, 1995; Farah et al., 1998).  The first system specializes in recognizing parts of objects and in Another theory concerning the role of the assembling those parts into fusiform gyrus is called the expert- distinctive wholes (feature analysis individuation hypothesis. According to this system) theory, the fusiform gyrus is activated when one examines items with which one has visual expertise The brain contains neurons that specialize Prosopagnosia—the inability to recognize in the perception of depth. These neurons, faces—implies damage to the as one might expect, are referred to as configurational system. binocular neurons. Agnosias and Ataxias The Environment Helps You See Agnosia have trouble perceiving sensory information (Moscovitch, Winocur, & Perceptual constancy occurs when our Behrmann, 1997). Agnosias often are perception of an object remains the same caused by damage to the border of the even when our proximal sensation of the temporal and occipital lobes distal object changes (Gillam, 2000). Disturbance in the temporal region of the Here we consider two of the main cortex can lead to simultagnosia. constancies: size and shape constancies. Prosopagnosia results in a severely Size constancy is the perception that an impaired ability to recognize human faces object maintains the same size despite changes in the size of the proximal stimulus. A different kind of perceptual deficit is The size of an image on the retina depends associated with damage to the how directly on the distance of that object from pathway. This deficit is optic ataxia, which is the eye. an impaired ability to use the visual system to guide movement (Borchers et al., 2013). Shape constancy is the perception that an object maintains the same shape despite Anomalies in Color Perception Color changes in the shape of the proximal perception deficits are much more common stimulus in men than in women, Depth Perception Rod monochromacy, also called achromacy. People with this condition have Depth is the distance from a surface, no color vision at all. It is the only true form usually using your own body as a reference of pure color blindness. In this condition the surface when speaking in terms of depth cones are nonfunctional. They see only perception. shades of gray as a function of their vision Monocular depth cues can be represented through the rods of the eye. in just two dimensions and observed with Dichromacy, only two of the mechanisms just one eye. for color perception work, and one is Binocular depth cues, based on the receipt malfunctioning. The result of this of sensory information in three dimensions malfunction is one of three types of color from both eyes (Parker, Cumming, & Dodd, blindness 2000).  deuteranopia (trouble seeing greens Binocular disparity, your two eyes send with symptoms similar to increasingly disparate (differing) images to protanopia) your brain as objects approach you.  tritanopia (confusion of blues and greens, and yellows that disappear Binocular convergence, your two eyes or appear as light shades of reds). increasingly turn inward as objects approach you. Your brain interprets these muscular movements as indications of distance from you.