Chapter Five - Knapp 2000

sensation

detection of physical energy by sense organs, including our eyes, ears, skin, nose, and tongue, which they relay information to the brain

perception

the brains interpretation of these raw sensory inputs

1. sensation
2. perception

(1)______ first allows us to pick up the signals in our environment
(2)______ then allows us to assemble these signals into something meaningful

transduction

the process by which the nervous system converts an external stimulus, like light or sound, into electrical signals

sense receptor

specialized cell responsible for converting external stimuli into neural activity for a specific sensory system

sensory adaptation

activation is greatest when a stimulus is first detected (ex: when you are wearing anew wristwatch, first aware of pressure on wrist but then no longer are aware its there// going to your friends house and it no longer has its scent)

psychophysics

the study of how we perceive sensory stimuli based on their physical characteristics

absolute threshold

the lowest level of a stimulus needed for the nervous system to react

just noticeable difference

the smallest change in the intensity of a stimulus that we can detect; detected one from another

webers law
(ex: the law states that the ratio of the increment threshold to the background intensity is a constant. So, when you are in a noisy environment you must shout to be heard while a whisper works in a quiet room)

there is a constant proportional relationship between the just noticeable difference and the original stimulus intensity

selective attention

the process of selecting one sensory channel and ignore and minimize others

filter theory of attention
(ex: what color shirt your professor was wearing vs what was the lesson about)

views attention as a bottleneck through which information passes. this mental filter anabas us to pay attention to important stimuli and ignore others

cocktail party effect

refers to our ability to pick out an important message, like our name, in a conversation that doesn't involve us. We don't typically notice what other people are saying unless its relevant to us.

inattentional blindness

failure to detect stimuli that are in plain sight when our attention is focused elsewhere

change blindness

failure to detect obvious changes in ones environment

binding problem

the problem of how the unity of conscious perception is brought about by the distributed activities of the central nervous system

light

electromagnetic radiation within the portion of the electromagnetic spectrum that can be perceived by the human eye

visible light

usually defined as having wavelengths in the range of 400-700 nanometers

scelera

the white of the eye

iris

the colored part of the eye, controls how much light enters the eye

pupil

circular hole through which light enters the eye.

the amount of light that enters the eye is controlled by the closing of the pupil as a reflex response to light or objects coming towards us; for when we try to process complex information life difficult math problems and physical attraction

pupil dilation psychological significance

cornea

part of the eye containing transparent cells that focus light on the retina; bends light that enters the eye

accommodation

lenses change shape to focus light on the back of the eyes to adapt to different perceived distances of objects

nearsightedness

results when images are focused in front of the rear of the eye due to our cornea being too steep or our eyes too long

farsightedness

results when our cornea is too flat or our eyes are too short

retina

membrane at the back of the eye responsible for converting light into neutral activity

fovea

central potion of the retina responsible for acuity

acuity

sharpness of vision

rods

enables us to see basic shapes and forms; black/white and low level light

cones

gives us our color vision

dark adaptation

time in the dark before rods regain maximum light sensitivity

ganglion cells

cells in the retinal circuit that contain axons, bundle all their axons together and depart the eye to reach the brain

optic nerve

contains the axons of ganglion cells, travels form the retina to the rest of the brain

because there is a place where the optic nerve connects to the retina; its the region on the retina containing no rods or sense receptors

why do we have a blind spot

trichromatic theory

the idea that color vision is based on our sensitivity to three primary colors (blue, green, and red)

opponent-process theory

the theory that we perceive colors in terms of three pairs of opponent colors: either red or green, blue or yellow, or black or white; the theory cannot explain afterimages which occur when stared at one color for a long time and then look away

sound
(low frequency = less air pressure = low pitch)
(high frequency = more air pressure = high pitch)

vibration, a kind of mechanical energy traveling through a medium, usually air: the disturbance created by vibration of molecules of air produces sound waves

pitch
ex: low frequency- low pitch

corresponds to the frequency of the wave

the amplitude or height of the sound wave corresponds to loudness

how is loudness related to sound waves

loudness

results in increased wave amplitude because there's more mechanical disturbance

timbre

complexity or quality of sound that makes musical instruments, human voices, or other sources sound unique

outer: pinna, ear canal
middle: ossicles
inner: cochlea, organ of corti, basilar membrane

name the structures found in the inner, middle, and outer ear

pinna

the part of the ear that we see, namely, its skin and cartilage flap

ear canal

has the simplest function; it funnels sound waves into the eardrum

ossicles

the three tiniest bones in the body-- includes the hammer, the anvil, and the stirrup; they vibrate at the frequency of the sound wave, transmitting it form the eardrum to the inner ear

cochlea

bony, spiral-shaped sense organ used for hearing, converts vibration into neural activity

organ of corti

tissue containing the hair cells necessary for hearing

basilar membrane

membrane supporting the organ of corti and hair cells in the cochlea

hair cells convert acoustic information into action potentials. Hair cells contain cilia that protrude into the fluid of the cochlea. When sound waves travel through the cochlea, the resulting pressure deflects these cilia, exciting the hair cells. That information feeds into the auditory nerve, which travels to the brain, through the thalamus which is a sensory relay station

how do hair cells contribute to hearing?w

place theory

specific place along the basilar membrane, matches the tone with a specific pitch

frequency theory

rate at which neurons fire the action potentials faithfully reproduces the pitch.

Volley theory

a variation of frequency theory that works for tones between 100 and 5,000 Hz

olfaction

our sense of smell

gustation

our sense of taste

savory, sweet, salty, bitter, and starch (meaty, Unami, and perhaps fat are other tastes)

the classic 5 tastes

taste buds

sense receptors in the tongue that respond to sweet, salty, sour, bitter, umami, and perhaps fat

parallel processing

the ability to attend to many sense modalities simultaneously

bottom-up processing

starts at the sensory receptors and works up to higher levels of processing; starts with raw stimuli we perceive and ends with our synthesizing them into a meaningful concept

top-down processing

starts with our beliefs and expectations which we impose on the raw stimuli we perceive

perceptual sets

when our expectations influence our perceptions

perceptual constancy

the process by which we perceive stimuli consistently across varied conditions (no matter what shape/size/color we see it as, we know its actual shape/size/color)

shape constancy

we still see a door as a door whether its completely shut, barely open, or more fully open even though these shapes look almost nothing like each other.

size constancy

our ability to perceive objects as the same size no matter how far away they are from us

color constancy

our ability to perceive color consistently across different levels of lighting

gestalt principles

are rules governing how we perceive objects as wholes within their overall context

proximity, similarity, continuity, closure, symmetry, and figure-ground

what are the 6 gestalt principles

proximity

objects physically close to each other tend to be perceived as unified wholes/ groups

similarity

all things being equal, we see similar objects as comprising a whole, much more so than dissimilar objects

continuity

we still perceive objects as wholes, even if other objects block part of them/ you view the dots as one continuous path not individual branches

closure

when partial visual information is present, our brains fill in what's missing (filling in the dotted shape)

symmetry

we perceive objects that are symmetrically arranged as wholes more often than those that aren't

figure-ground

perceptually, we make an instantaneous decision to focus attention on what we believe to be the central figure, and largely ignore what we believe to be the background ("do you see the faces or the vase first?" type of exercises)

depth perception

ability to judge distance and three-dimensional relations

binocular depth cues and monocular depth cues

what are the two types of depth perception

binocular depth cues

stimuli that enables us to judge depth using both eyes

monucular depth cues

stimuli that enables us to judge depth using only one eye

binocular disparity

when our left and right eyes transmit quite different information for near objets but see distant objects similarly

binocular convergence

when we look at nearby objects and focus on them reflexively by using our eye muscles to turn our eyes inward