Selective Attention: This is defined as the focusing of conscious awareness on one particular stimulus. Consciousness is limited and focuses on only one thing at a time.
Sensory Input vs. Processing: By estimate, human senses take in approximately 11000000bits of information per second. However, humans consciously process only about 40bits of that total information. Attention is captured by things deemed important.
Selective Attention and Accidents: Shifting attention more than realized can lead to tragic accidents.
- Attentional Toggling: Rapidly switching between activities, particularly complex tasks, causes a "toll"—a slight and sometimes fatal delay in coping.
- Distracted Driving Statistics: Each day, distracted driving results in the deaths of approximately 9Americans. Using a phone (including hands-free) increases the accident risk by 4times, making it equal to the risk of drunk driving.
Inattentional Blindness: This occurs when a person fails to see visual objects because their attention is directed elsewhere.
- Magicians and Thieves: These individuals often exploit inattentional blindness to perform tricks or crimes.
- Change Blindness: A specific form of inattentional blindness where an individual fails to notice changes in their environment.
Perceptual Set: A mental predisposition that leads someone to perceive one thing and not another. It is a form of top-down processing and influences sight, hearing, and taste.
- Stereotypes: Stereotypical beliefs regarding culture, gender, ethnicity, age, and abilities can color perceptions.
Context Effects: Contextual surroundings influence perception. For example, hearing "eel is on the wagon" leads to perceiving "wheel," while "eel is on the orange" leads to hearing "peel."
Motivation and Perception: Motives provide energy toward goals and alter perception. Desirable objects appear closer than they are, and a walking destination seems farther when a person is tired.
Emotion and Perception: Emotions act as a filter for stimuli.
- Music: Cheerful music speeds up the identification of happy emotion words. Sad music can predispose people to perceive sad meanings in homophonic words (e.g., hearing "mourning" instead of "morning" or "pain" instead of "pane").
Perceptual Organization and Interpretation
Gestalt Psychology: The term "Gestalt" refers to an organized whole. Gestalt psychologists argue that we tend to integrate pieces of information into meaningful wholes, suggesting that the brain does more than register information; it filters and constructs perceptions.
Form Perception:
- Figure-Ground: The organization of the visual field into objects (figures) that stand out from their surroundings (ground). This is the first perceptual task for the eye-brain system and applies to hearing as well. A single stimulus can sometimes trigger multiple perceptions.
- Grouping: Once figure and ground are discriminated, the brain organizes the figure into meaningful forms. Grouping is the tendency to organize stimuli into coherent groups.
Depth Perception: This is the ability to see objects in three dimensions despite the retina receiving two-dimensional images. It allows us to judge distance.
- Visual Cliff: A laboratory device used to test depth perception in infants and young animals. During tests, infants refused to lean over a perceived cliff.
Binocular Cues: Depth cues that depend on both eyes.
- Convergence: A cue for the distance of nearby objects enabled by the brain combining retinal images.
- Retinal Disparity: The brain computes distance by comparing the images from both eyes. The greater the disparity (difference) between the images, the closer the object is to the viewer.
Monocular Cues: Depth cues available to each eye independently, often creating illusions of depth on flat surfaces.
- Relative Clarity: Objects that are sharp and detailed are perceived as closer than hazy objects.
- Relative Size: Objects that create a smaller retinal image are perceived as being farther away.
- Texture Gradient: Coarser and distinct textures are seen as closer; smoother, less distinct textures are seen as farther.
- Linear Perspective: Parallel lines that converge in the distance appear farther away.
- Interposition: If one object partially blocks the view of another, the blocking object is perceived as closer.
Motion Perception: The brain assumes shrinking objects are retreating and enlarging objects are approaching.
- Developmental Risks: Children have not fully developed this ability, which increases their risk for pedestrian accidents.
- Size-Speed Illusion: When large and small objects move at identical speeds, larger objects appear to move more slowly.
- Stroboscopic Movement: An illusion of continuous movement created by viewing a rapid series of slightly varying still images.
- Phi Phenomenon: An illusion of movement when two or more adjacent lights blink on and off in quick succession.
- Autokinetic Effect: The illusory movement of a stationary spot of light in a dark room.
Perceptual Constancy: Perceiving objects as stable (color, brightness, shape, size) even as illumination and retinal images change.
- Color Constancy: Perceiving familiar objects as having the same color even if lighting changes the reflected wavelengths. This involves comparing an object to its surroundings.
- Brightness Constancy: Perceiving constant brightness despite varying illumination. This relies on relative luminance (light reflected relative to surroundings).
- Shape and Size Constancy: The ability to perceive the form and size of familiar objects as constant even when retinas receive changing images or distances vary.
Perceptual Interpretation:
- Restored Vision: Individuals born blind who later gain sight can distinguish figure from ground and colors (suggesting these are innate), but they often cannot visually recognize objects previously known only by touch.
- Critical Period: An optimal period in early life when exposure to certain stimuli is required for normal sensory/perceptual development.
- Perceptual Adaptation: The ability to adjust to changed sensory input, such as an inverted or displaced visual field.
Thinking, Concepts, and Creativity
Cognition: All mental activities associated with thinking, knowing, remembering, and communicating.
Metacognition: Thinking about thinking; the act of tracking and evaluating mental processes.
Concepts: Mental groupings of similar objects, ideas, or people that simplify thinking.
- Prototypes: A mental image or best example of a category. Matching new items to a prototype allows for quick sorting, though category boundaries may blur as items move away from the prototype.
Jean Piaget's Theories: Intellectual progression is a struggle to make sense of experiences.
- Schema: A framework that organizes and interprets information.
- Assimilation: Interpreting new experiences based on existing schemas.
- Accommodation: Adapting existing schemas to incorporate new information.
Creativity: The ability to produce new and valuable ideas.
- Convergent Thinking: Narrowing solutions to find the single best answer (required for aptitude tests like the SAT).
- Divergent Thinking: Expanding the number of possible solutions; thinking that moves in different directions (required for creativity sessions).
- Functional Fixedness: An obstacle to creativity where prior experiences inhibit the ability to see new uses for objects.
- Sternberg's Five Components of Creativity: Expertise