UNIT 3 Sensation and Perception

sensation

process in which we receive information from the environment

transduction

transformation of physical stimulation (such as light or sound waves) into the neural impulses to be sent to the brain

perception

interpretation of information from the environment so that we can identify its meaning

bottom-up processing

analysis that begins with the sensory receptors and works up to the brains interrogation of sensory information (initial sensation)

top-down processing

information processing guided by higher level mental processes as when we construct perceptions drawing on our experience and expectations (interpretation from previous knowledge)

Inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment

selective attention

ability to focus on one stimulus while excluding other stimuli that are present

cocktail party effect

ability to tend to one voice among many while excluding other noises

Divided Attention

ability to respond to more than one stimulus

absolute threshold

the level of stimulus necessary for a stimulus to be detected

Difference Threshold/Just noticeable difference

the smallest level change in a stimulus that a person can detect over 50 percent of the time

webers law

the size of JND is proportional to the intensity of a stimulus

signal detection theory

suggests how individuals are able to detect a minimal stimulus signal among other background stimuli

perceptual set

readiness to detect a particular stimulus in a given situation

priming

the activation often consciously of certain associations thus predisposing ones perception, memory, or response (ex: a_tom_b_L_)

Consciousness

our awareness of ourselves and our environment

Biological Clock

controlled by your hypothalamus

circadium rhythm

physical,mental,behavioral changes that follow a 24 hour cycle

suprachiasmatic cells

pair of cell clusters in the hypothalamus that controls the circadium rhythm - responds to light causing pineal gland to adjust melatonin and modify sleepiness

pineal gland

produces sleep inducing hormone melatonin

Desynchronization

Disruption in circadium rhythm cycle (jet lag)

Ultradian Rhythms

those that occur more than once a day (appetite and hormonal release)

Infradian Rhythms

those that occur monthly or yearly (menstrual cycle)

Hypnagogic Sleep

relaxed and drowsy state before falling asleep

sleep

periodic natural loss of consciousness

EEG

have enabled psychologists to learn more about sleep processes

Non Rem 1

lightest sleep spent 4-5 percent in; EEG reads theta waves; drifting thoughts,images,hallucinations

Non Rem 2

periodic bursts of brain activity called sleep spindles (k complexes); sleep talking can occur; heart rate, body temp, respiration, muscle tension decrease

Non Rem 3

emits large slow delta waves, growth hormone is secreted, hardest to be awaken from, chooses what short term memories to store

REM

Rapid Eye Movement - dreaming, increased heart rate, rapid breathing, sexual arousal; develops the brain, implicit memory, emotional awareness; increases visuospatial regions, motor cortex, hippocampus, and amygdala activity by 30 percent.

Paradoxical Sleep

In REM; internally aroused externally calm

Sensory Adaption

the diminishing responsiveness of our sensory systems to persistent stimulation

transduction

transforming of stimulus energies such as sights, sounds, and smells into neuro impulses

wavelength

the distance from one wave peak to the next-determined by hue

Intensity

the amount of energy in light waves determined by a waves amplitude or height

We dont see color

we see electro magnetic energy

cornea

protects the eye and bends light to focus it - light enters through it

pupil

small adjustable hole that light enters

iris

colored muscle that adjusts light intake and controls pupil size

lens

focuses incoming light

retina

multi-layered tissue on the eyeballs sensitive inner surface - has rods and cones

rods

retinal receptors that detect black white and grey

cones

retinal receptor cells that function in daylight or well lit conditions detects detail and color sensations

how optic nerve is formed

neural signals activate bipolar cells, which activate ganglion cells which form the optic nerve - carries neural impulses from the eye to the brain

optic nerve

carries visual information from the retina to the brain

blind spot

optic nerve exits the eye and where there are no photo receptors

fovea

retinas area of central focus - highest concentration of rods and cones (visual acuity)

feature detectors

cells that have the ability to respond to a scenes specific features

parallel processing

simultaneous processing of several aspects of a problem simultaneously in different areas of the brain (ex: playing catch)

young helmoltz trichomatic theory

the retina contains 3 different color receptors (red green and blue) and together can produce the perception of any color

opponent processing theory

the theory that opposing retinal processes enable color vision

color processing stages

1) the retinas red green and blue cones respond to different color stimuli as the YH3 color theory suggests

2) their signals are then processed by nervous systems opponent process cells to see after images.

color blindness

more common in males because it is sex linked to the x chromosome

Dream

sequence of images emotions and thoughts passing through a sleeping persons mind (4-5 dreams per night)

manifest content

remembered storyline of a dream

latent content

underlying meaning of a dream

Activation Synthesis Theory

dreams are the result of the cerebral cortex making sense of activity of other parts of the brain

REM rebound

tendency for rem sleep to increase following rem deprivation

physical addiction

need the drug or body goes through withdraw

psychological addiction

want the drug really bad but the body does not need it

depressants

reduce cns activity and increase gaba

stimulants

speed up the cns, reduces gaba, increases norepinephrine and dopamine

opiates/narcotics

agonists for endorphins, highly addictive, stimulate glutamate receptors, physically change neuron structure and make it need drug to function (heroine,codeine,oxycodone,morphine)

hallucinogens/psychedelics

time is distorted, sounds cause visual sensation, stimulate seretonin and dopamine (Ketamine, Marijuana, Ecstacy)

Insomnia

refers to consistent difficulties in either going to sleep or staying asleep

Narcolepsy

chronic disorder that is marked by excessive sleepiness and sleep attacks- accompanied by brief periods of rem sleep and muscle paralysis (cataplexy)

sleep apnea

repeated periods during sleep when people stop breathing

rem behavior disorder

voluntary muscles are not paralyzed and sleepers act out dreams

Night terrors

frightening experiences that often start with a scream followed by waking in a fearful state- no memory of experience

Nightmares

occur during rem sleep has frightening images and thoughts

sleep walking

person will get up and walk around sound asleep

Gustatory System

the sense associated with the perception of taste

location of primary gustatory cortex

located near the face area of the somatosensory cortex of the parietal lobe

sensory interactions

the principle that one sense may influence another (smell of food influences taste)

smell is olfaction

close connection with memory

gesalt

an organized whole -emphasized tendency to integrate pieces of information into meaningless wholes

figure

the part of an image that stands out

ground

part of an image that does not stand out

laws of gesalt psychology

proximity, closure, similarity, law of continuity, connectedness

depth perception

the ability to see objects in 3 dimensions even though the images that strike the retina are 2 dimensional

binocular cues

depth cues such as retinal disparity that depend on the use of two eyes

retinal disparity

when the brain compares two images from the retinas of both eyes so it allows us to perceive depth efficiently

Monocular Cues

depth cues such as interposition and linear perspective - creating an illusion of depth on a flat surface (available to either eye and let us judge distance far away)

interposition

something close blocks something far away

linear perspective

thing at vanishing point looks bigger

texture gradient

determining depth based off of them being merged together

phi phenomenon

two or more adjacent lights blink on and off in quick succession

audition

the sense or act of hearing

frequency

the number of cycles completed by a wave in a given amount of time - determines pitch

amplitude

physical strength of a wave - the volume measured in decibels

cochlea

hair cells bundle together to let us hear

basilar membrane

in cochlea has hair cells on it-contributes to hearing, understanding, and perception of sound

Herman Von Helmholtz place theory

theory that links pitch to the place where the cochlea membrane is stimulated - high frequency beginning of cochlea and vice versa

Frequency Theory

the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone

conduction deafness

inability to hear resulting from damage to structures of the middle or inner ear

nerve deafness

an inability to hear linked to a deficit in the bodys ability to transmit impulses

Kinesthetic Sense

the system for sensing the position and movement of an indivisuals body parts

vestibular sense

the sense of body movement and position, including balance

gate control theory

A delta fibers sens instantaneous pain dignals - c fibers send slow throbbing pain signals (A theory spinal chord has shut off valve)