Terms Flashcards
Sensation “Detection & Encoding”
The senses collect some kind of information from the environment and convert it to a signal that can travel to the brain
-Sensing our environment through touch, taste, sight, sound, and smell (nervous system)
-Our senses depend on each other
Transduction
The transformation of stimulus energy to electrochemical energy of neural impulses (except smell)
Perception “Interpretation”
Process by which we select, organize, and interpret sensory information in order to recognize meaningful objects and events
-Information is organized, interpreted, and consciously experienced
-Enables recognition of meaningful events
Bottom-Up Processing “Sensory Analysis”
Involves starting with an incoming stimulus and working upwards until a representation of the object is formed in our minds
-Begins at entry level with our senses can detect
-Requires no previous knowledge or learning
Top-Down Processing
Form our perceptions starting with a larger object, concept, or idea before working our way toward more detailed information
-Big Picture, Tiny Details
-Influenced by prior experience and current expectations
Absolute Threshold
Smallest level of stimulus that can be detected, usually defined as at least half the time (Point something becomes noticeable)
-How dim can a light be or how soft can a sound be and still be detected half of the time
Signal Detection Theory
Theory predicting how and when we detect the presence of a faint (weak) stimulus (signal) amid background stimulation (noise)
-Assumes there is no single absolute threshold, detection depends partly on a person’s experience, expectations, motivation, and level of fatigue
Subliminal Sensation
When stimuli are below one’s absolute threshold for conscious awareness
-Much of our information processing occurs automatically, out of sight, off the radar screen of our conscious mind
Difference Threshold “Just Noticeable Difference (JND)”
The amount something must be changed in order for a difference to be noticeable, or detectable at least half the time
Weber’s Law
The principle that to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than constant amount)
-Bigger stimuli require larger differences to be noticed
-Light, 8%
-Weight, 2%
-Tone, 3%
Sensory Adaptation
Reduction in sensitivity to a stimulus after constant exposure to it
-Reduces our awareness of a constant stimulus, it helps free up our attention and resources to attend to other stimuli in the environment around us
Selective Attention
We center our attention on certain important elements of our environment while other things blend into the background or pass us by completely unnoticed
-We sense a lot of information. Scientists estimate we observe 11,000,000 its of info per second. But we weed out all but 40 bits
Divided Attention “Multitasking”
Occurs when mental focus is on multiple tasks or ideas at once
-Divided attention does decrease the amount of attention being placed on any one task or idea is there are multiple focuses going on at once
Pupil
Adjustable opening in the center of the eye through which light enters, controls the amount of light that enter the eye
Iris
A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening (colored part of eye)
Crystalline Lens “Lens”
The transparent structure behind the pupil that changes shape to help focus images on the retina, focus eye on near or far objects.
Retina
Light-sensitive layer that lines the back of the eye
-Retina contains photoreceptors that absorb light and then transmits those signals through the optic nerve to the brain
Photorecpetors
Convert light energy to electrochemical neural impulses that are conducted to our brain
-Rods and Cones
-Our retinal contains 120 million rods and 1 million cone receptors
Cones
Light-detecting cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions, directly involved in our ability to perceive color
Rods
Specialized photorecpetors that work well in low light conditions, involved in our vision in dimly lit environments as well as in our perception of movement on the periphery of our visual field
Optic Nerve
The nerve that carries neural impulses from the eye to the brain (cross to opposite side of brain, once inside the brain, visual information is sent via a number of structures to the occipital lobe at the back of the brain for processing.
Blind Spot
The point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there
-Sacade, eyes have rapid movement from side to side to help fill in the missing information created by the blind spot.
Young-Helmholtz Trichromatic (three-color) Theory
There are three receptors in the retina responsible for the perception of color (green, blue, red_
-Colors red, blue, and green can be combined to create all colors of light
Color-Deficient Vision
Simply lacking functioning-red or green-sensitive cones or sometimes both, missing cones that respond to a specific color
-Monochromatic (one-color) or dichromatic (two-color) instead of trichromatic, making it impossible to distinguish the red and green.
