Chapter 4 - Sensation, Attention, and Perception

Transducers

sense organs that convert one kind of energy into another (environment - light, mechanical, chemical—> action potential understood by brain)

Sensation

process by which info from the physical world is detected by these sense organs - front end processing

Psychophysics

study of how the mind interprets physical properties of stimuli

Absolute Threshold

min. amount of physical energy that can be detected 50% of time - detection itself

Difference Threshold

min. difference in physical energy b/w two stimuli that can be detected 50% of the time

ability to tell apart

Sensory Adaption

sensory receptors respond less overtime to unchanging stimuli ie. smell

Featre Detector

cells in cortex that respond to a specific attribute of an obect

Perceptual Features

attributes of a stimulus, lines, shapes, edges, colours

Lack of Specific Transducers

lack of sensory organs to transduce some forms of energy

Restricted Range

only transduce fraction of their target energy range (ie, eyes can inly transduce a fraction of the electromagnetic spectrum)

Hue

colour of light, determined by wavelength

Saturation

pureness of light/colour

Brightness

amplitude or height of the wavelength

Cornea

curved, transparent, protective layer, where light enters the eye

Lens

clear structure behind the pupil, bends light towards the retina

Accomodation

change in lens shape to enable sight of close and far obects

Hyperopia

farsightedness, short eye, convex lens

Myopia

near sightedness, long eye, concave

Astigmatism

defect in cornea, lens or eye causing areas of vision to be out of focus, misshapen lens

Presbyopia

farsightedness caused by aging

Rentina

back of the eye where lens focuses light rays

Cones

colour photoreceptors

Rods

dim light receptors, black and white sensation

Visual Acuity

sharpness of visual perception

Blind Spot

area in retina where optic nerve exits, no photoreceptor cells

Optic Nerve

conveys visual info from retina to brain

Fovea

tiny spot in center of retina where visual acuity is greatest, only cones

Colour Blindness

total inability to perceive colour, lack cones or functioning cones

Colour Weakness

inability to distinguish some colours

Peripheral Vision

vision at the edges of the visual field

Dark Adaption

increased light sensitivity under low light conditions, pupil opens to allow more light in

Pupil

black opening inside iris, allows light to enter

Iris

coloured part of the eye, surrounds pupil

Trichromatic Theory of Colour

based on three cone types - red, blue, green

happens at the retina

Opponent Process Theory of Colour

vision analyzes colour as either/or processes, black or white, green or red, yellow or blue

happens in the brain

Pitch

how high or low a tone sounds, frequency of sound wave

Loudness

volume of sound, related to amplitude or height

Eardrum

or tympanic membrane

membrane that vibrates in response to soundwaves, transmits them inwards

Pinna

visible outer of the ear, funnels sounds

Ossicles

incus, malleus, stapes

link eardrum with cochlea

Cochlea

snail shaped organ of inner ear, contains sensory receptors

Oval Window

moves back and forth, triggering movement of liquid in cochlea

in between stapes and cochlea

Basilar Membrane

vibrations triggered by fluid waves in cochlea

Hair Cells

in basilar membrane, receptor cells that translate vibrations into nerve impulses

Stereocilia

atop haircells, trigger action potential

Conductive Hearing Loss

poor transfer of sounds from ear drum to inner ear

Sensorineural Hearing Loss

caused by damage to haircell or auditory nerve

Noise-induced Hearing Loss

damage haircells caused by exposure to excessively loud noice

Frequency Theory of Hearing

Pitch is decoded by the rate at which hair cells are firing

Place Theory of Hearing

higher or lower tones excite specific cochlear areas

Olfaction

sense of smell

Gustation

sense of taste

Skin Senses

sense of touch, pain, pressure, temperature

Vestibular Sense

perception of gravity, blance, and acceleration

Lack and Key Theory of Olfaction

odours are related to the shapes of their chemical molecules

Taste Buds

receptor cells for taste

sweet, sour, bitter, salty, umami

Warning System

pain based on LARGER nerve fibers, warns body damage may be occuring

Reminding System

pain based on SMALL fibers, reminds brain that body has been injured, slower, nagging pain

Gate Control Theory

proposes that pain messages pass through neural “gates” in the spinal cord

Multimodal Integration

process by which the brain combines information coming from multiple senses

driven by the elephant

Selective Attention

giving priority to a particular incoming sensory message

Intensity

intense stimuli command attention, bright lout

Contrast

change from usual and expected

Personal Importance

cocktail party effect, hearing your name in a room

Goals

will it allow you to achieve your own goals

Inattentional Blindness

failure to notice stimulus because attention is focused elsewhere, unexpected or focused on goal

Change Blindness

failure to notice background is changing because attention is focused elsewhere

Mindwandering

attention is withdrawn from physical environment to focus on internal events

Synethesia

stimulation, organization, and interpretation of sensory input

Illusion

misleading or misconstructed perception

Hallucination

perception with no basis in reality

Perceptual Construction

a mental model of external events

Bottom-Up processing

organizing perceptions by beginnin with low level features, build perception

Top-Down Processing

perception guided by prior knowledge or expectations

Figure-Ground Organization

organizing a perception so that part of a stimulus appears to stand out as a figure against a less prominent background

Shape Constancy

perceived shape of an object remains constant, despite changes in retinal image

Size Constancy

perceived size of an object remains constant, despite changes in retinal image

Depth Perception

the ability to see 3D space and judge distances accurately

Depth Cues

features of the environment and messages from the body that supply info about distance and space

Binocular Depth Cues

perceptual features that require two eyes

Retinal Disparity

binocular depth cue

perception of space and depth as a result of each eye receiving different images

Convergence

binocular depth cue

degree to which eyes turn into focus on one object

Monocular Depth Cue

perceptual features that require one eye

Pictorial Depth Cues

monocular depth cues

found in painting, drawings and photos, impart info about space depth and distance

Virtual Reality

sensory stimuli provided by computer software to stimulate real events

help anxiety, addictions, PTSD