Unit 3

Sensation/ Bottom-up processing

sensory receptors and the nervous system receive stimuli from our world which begins with the senses and goes to the brain

Perception/ Top-down processing

the process of organizing and interpreting information processing guided by higher-level mental processes

Selective Attention (opposite is divided attention)

we focus our attention on only a limited aspect of all that we experience

Inattentional Blindness

failing to see visual objects when our attention is drawn elsewhere

Change Blindness

the failure to notice significant changes in our environment

Fechner's Absolute Threshold

the minimum stimulus necessary to detect a particular stimulus 50% of the time

Signal Detection Theory

absolute thresholds vary depending on experience, expectations, motivation, and level of fatigue; when we have stimuli happening at the same time we tend to detect the one that is most important to us (This theory assumes that there are no absolute thresholds).

Subliminal Threshold

below one’s absolute threshold for conscious awareness

Difference Threshold

the smallest amount of change required before we notice that two things are different

Weber’s Law

to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

Sensory Adaptation

our diminishing sensitivity to an unchanging stimulus

Transduction

the process by which our sensory systems convert energy into neural impulses (prevalent with vision and hearing)

Wavelength

the distance from the peak of one light or sound wave to the peak of the next

Light Hue

the dimension of color that is determined by the wavelength of light

Light Intensity

the amount of brightness or dimness

Cornea

protective covering of the eye

Pupil

adjustable opening in the center of the eye

Iris

the muscle that controls the opening of the pupil

Lens

transparent structure behind the pupil

Retina

contains of rods and cones/ inverts images

Accommodation

the process by which the eye lens changes shape to focus on near or far objects in the retina

Rods

detect black, white, and gray and are necessary for peripheral vision and twilight vision

Cones

concentrated near the center of the retina (fovea) and are involved in Foveal vision (opposite of peripheral vision), they function in daylight and well-lit conditions, they detect detail (acuity) and color; your central vision

Blind Spot

where the optic nerve leaves the eye

Foveal Vision

center of vision where details are sharpest (opposite of peripheral vision)

Peripheral Vision

what you can see from the corner of your eye

Feature Detectors

nerve cells in the brain (in the visual cortex) that respond to specific features of the stimulus, such as shape, angle, and movement

Hubel and Wiesel's Feature Detector Study

discovered it with cats in two different environments

Young – Helmholtz Trichromatic Theory

we have three types of cones in the retina that detect red, green, and blue. These colors are activated in different combinations to produce color

Opponent-Process Theory

sensory receptors in the retina come in pairs. If one sensor is stimulated, then the other is inhibited from firing (explains afterimages and color blindness)

Pairs: Red/Green, Yellow/Blue, Black/White

Amplitude

height of the wave/determines loudness (loud sounds- tall waves and soft sounds- short waves)

Frequency

length of the wave/determines pitch (high pitch- faster frequency and low pitch- slower frequency)

Pitch

the dimension of frequency which is determined by the wavelength of a sound wave

Middle Ear

• Eardrum connects to the middle ear (three bones: hammer, anvil, and stirrup)

• Vibrations go to the inner ear

Cochlea

a snail-shaped fluid-filled tube through which sound waves trigger neural impulses

Inner Ear

waves travel through the basilar membrane containing hair cells that bend

Basilar Membrane

is located in the cochlea of the inner ear and vibrates, stimulating the hair cells

Conduction Hearing Loss

due to damage of the mechanical system that conducts sound waves to the cochlea (outer or middle ear)

Sensorineural Hearing Loss (aka nerve deafness)

due to damage to the cochlea’s receptor cells or the auditory nerves (inner ear)

Kinesthesis

gives the body feedback about the movement and position of specific body parts

Vestibular Sense

keeps track of the overall orientation of the body. Provides a sense of the body’s movement and position, including balance

Gate-Control Theory

Explains how we experience pain. The spinal cord contains a neurological “gate.” Some pain messages have higher priority than others. The high-priority message is sent and the “gate” swings open and allows it to pass to the brain. The “gate” closes for low-priority messages – thus we do not feel them.

Gustation (taste)

• Five taste sensations (bitter, sweet, sour, and salty)

• Umami - separate from other 4, meaty, broth-like, or savory taste

Olfaction (smell)

• chemical sense

• smell

Gestalt

a German word meaning “whole”, perception of the whole exceeds the sum of its parts

Binocular Cues

depth cues that depend on the use of two eyes

Gibson’s Visual Cliff

she used a glass cover drop-off to test depth perception in infants and young animals. Most infants and young animals would refuse to crawl onto the glass – our capacity to understand depth is innate

Retinal Disparity

using two eyes, the brain computes distance. The greater the disparity (difference) between the two images, the closer the object; each eye sees slightly different view of the object

Monocular Cues

distance cues that can be used with either eye alone

Figure-ground

the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)

Similarity

the tendency to group alike figures together

Proximity

the tendency to group nearby objects together

Continuity

the tendency to perceive a smooth pattern

Connectedness

when objects are uniform and linked, the tendency to perceive spots, lines, or areas as a single unit

Closure

the tendency to fill in the gaps to create a meaningful whole

Depth Perception

the ability to see objects as three-dimensional, depth perception allows us to judge distance

Relative Height

objects in our higher field of vision are perceived as farther away

Relative Size

smaller images are farther away

Interposition

if one object blocks the view of another, it is perceived as closer

Linear Perspective

parallel lines appear to converge with distance

Relative Clarity

hazy objects are far away, clear objects are closer

Light and Shadow

nearby objects reflect more light

Relative Motion (Motion Parallax)

as we move, objects that are stable appear to move

Texture Gradient

coarse and distinct textures are close, fading textures are farther away

Phi Phenomenon

movement is created when two or more lights blink on and off in quick succession

Size Constancy

even when our distance changes we perceive items as remaining the same size

Shape Constancy

even when our retinal images change, we perceive objects as maintaining a certain shape.

Color Constancy

even when illumination changes we perceive objects as having a consistent color

Perceptual Adaptation

the ability to adjust in an artificially displaced or even inverted vision

Perceptual Set (aka expectancy set)

a mental predisposition causes you to perceive an event in a way that matches your beliefs

Synesthesia

a neurological condition in which information meant to stimulate one of your senses stimulates several of your senses (seeing numbers or smelling words)