AP Psychology Cognition: Perception PDF

## AP Psychology: Cognition: Perception ### Guided Notes 2.1 **Unit 2: Cognition (15-25%)** * Corresponding Module(s): 20-21, 23 * CED Topic: 2.1 ### Part 1: The Basics * **Let's Review!** * **Sensation:** Involves *receiving info* from the environment (through our senses!), *converting* it...

## AP Psychology: Cognition: Perception ### Guided Notes 2.1 **Unit 2: Cognition (15-25%)** * Corresponding Module(s): 20-21, 23 * CED Topic: 2.1 ### Part 1: The Basics * **Let's Review!** * **Sensation:** Involves *receiving info* from the environment (through our senses!), *converting* it into a neural message (transduction), and sending it to the *brain* to be interpreted * **Perception:** Involves *organizes* and *interprets* that sensory information * **Perception** is influenced by whether one primarily relies on external sensory information (bottom-up processing) or internal prior expectations (top-down processing) ### Top Down Processing * **Bottom-up Processing:** * Analysis that begins with *sensory receptors* and works up to the brain's integration of sensory information. * Relies on *external* sensory information of basic elements or features to *build* a perception * **Top-Down Processing:** * Schemas and perceptual sets are *internal factors* that *filter* perceptions of the world and help guide us for *organizing* and understanding our world. * Schemas: Mental framework for organizing * Example: We have a schema for a field and what kinds of animals/plants may be found in it...but for most of us, naked people is not included in that schema! * Perceptual Set: The *readiness* to perceive something in a *particular way* or having an expectation for a stimulus * Heavily influenced by our pre-existing schemas which influence how we *interpret* ambiguous sensations * Example: see "Let's Practice" and write down what you see * *External factors* that filter perceptions of the world include: * **Contexts:** A given stimulus may trigger different perception because of the immediate context * Example: How tall do you think the player in yellow is? * **Cultural Experiences:** A given stimulus may trigger different perceptions because of *cultural* experiences * Example: What is above the woman's head? ### Part 2: Attention * **Attention:** An *interaction* of sensation and perception that is affected by internal and external processes * Millions of stimuli compete for your attention at any given time. * **Selective Attention:** The *focusing* of conscious awareness on a *particular stimulus* to the *exclusion* of others in a world filled with *many* stimuli * Allows a person to function in a world filled with many stimuli * **Cocktail Party Effect:** A form of selective attention in which you are able to focus on a single *microphone* among a mixture of conversations and *background noises* * Can also detect mentions of *our name* ignoring other conversations or specific topics in noisy room * Sometimes we lose our *awareness of time* and the *presence of others* around us ### Inattentional Blindness * **Failing to see:** visible objects when our attention is directed elsewhere * **Change Blindness:** A form of inattentional blindness in which individuals don't notice a change in the environment after a brief visual interruption or *inattention*. ### Part 3: Gestalt Principles * **Gestalt Principles:** * How do we form meaningful perceptions from sensory information? * We organize it into a gestalt, or a "whole" (wholes), as opposed to examining them as distinct pieces * Humans group stimuli into *meaningful units* * **Figure-Ground:** The perceptual tendency to organize stimuli into objects that *stand out* from their surrounding * **Figure:** Object(s) that stands out or draws one's *attention* * **Ground:** Surrounding *visual field* * **Grouping:** The perceptual tendency to organize stimuli into *understandable groups* * Several principles of grouping include: * **Similarity:** The tendency to perceive items that are *alike* (have similar *color*, *shape*, orientation, or texture) as a unified whole or group * **Proximity:** The tendency to perceive nearby/physically *close* objects as a group * **Closure:** The principle of making a whole or *completed* object by *filling in the gaps* ### Part 4: Depth Perception * **Depth Perception:** * The ability to see objects in *three dimensions*, despite the fact that our retinas take in only *2 dimensions*. * Allows us to judge *distance* * Involves *binocular* depth cues and *monocular* depth cues. * **Binocular Depth Cues:** Depth cues, such as *retinal disparity* and *convergence*, that depend on the use of *two eyes* (and *two retinas*) * **Retinal Disparity:** * Retinas are approximately 2.5 inches apart; "see" *two different* images * Difference between the two images allows for the *calculation of distance* * The *greater* the difference, the *closer* the object * **Convergence:** Determines depth based on how much *both eyes rotate inward*: * The *more inward* the difference, the *closer* the object. * **Monocular Depth Cues:** Depth cues that require the use of *only one eye* to give the illusion of *depth* on a flat or two-dimensional surface * *Monocular depth cues include:* * **Linear Perspective:** Parallel lines appear to *converge* as they move *farther* into the distance * **Interposition:** When one object *partially blocks* our view of another, we perceive it as *closer* * **Relative size:** If we assume two objects are *similar in size*, most people perceive the one that casts the *smaller retinal image* as *further away* * The *larger* the object, the *closer* it is to the viewer. * **Relative Clarity:** Objects that appear *sharper* are perceived as *closer* than objects that appear *hazy* or *blurry*. * **Texture Gradient:** A key factor in depth perception based on how *light travels* through the atmosphere. * The tendency for textured surfaces to appear *smoother* and finer as the *distance* from the viewer *increases.* ### Part 5: Visual Perceptual Constancies * **Color Constancy:** The ability to perceive familiar objects as having *consistent color* even if changing *illumination* alters *wavelengths* reflected by the object * **Size Constancy:** The tendency to interpret an object as always being the *same size* (actual size) despite its *distance* * **Shape Constancy:** The understanding that an object's *shape* remains the same even though the *angle* it may change its shape on the retina * **Light/Brightness Constancy:** The ability to see an object as having a *constant proportion of brightness* no matter how the *lighting conditions* change. ### Part 6: Apparent Movement * **Apparent Movement:** Movement can be *visually perceived* even when objects are *not actually moving*. * The illusion of motion by the *rapid projection* of *slightly changing* images * Concept behind the development of *him animation* * **Stroboscopic Movement:** * The illusion of motion when *fixed lights* are turned on and off in a *sequence*. * **Phi Phenomenon:** The illusion of motion when *fixed lights* are turned on and off in a *sequence*. ### Let’s Practice! | 1. Difference in the images each eye receives when focusing on the same object | Convergence | | :------------------------------------------------------------------------------------ | :-------------------------------------------------------------------: | | 2. Illusion of motion with rapid projection of slightly changing images | Stroboscopic Movement | | 3. Objects that appear sharper are perceived as closer than objects that appear hazy or blurry | Relative clarity | | 4. Illusion of motion when fixed lights are turned on and off in a sequence | Phi Phenomenon | | 5. Determines depth based on how much both eyes rotate inward | Retinal disparity | | 6. When one object partially blocks our view of another, we perceive it as closer | Interposition |