Sensation and Perception

sensation

detecting physical energy from your environment and encoding it into neural signal

sensory receptors

sensory nerve endings that respond to stimuli

perception

interpreting sensations, enabling you to recognize meaningful objects and events

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain, ex. sensation

top-down processing

higher level mental processing using our experience and expectations (CORTEX), ex. perception

selective attention

the focusing of conscious awareness on a particular stimuli

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failure to notice changes in the environment

transduction

converting one form of energy to another

psychophysics

studying relationships between physical characteristics of stimuli, such as their intensity, and our psychological experience of them

absolute threshold

minimum stimulus needed to detect it 50% of the time

signal detection theory

predicts when we will detect weak signals, considers environmental factors

subliminal

below absolute threshold

difference threshold

just noticeable difference, minimum difference between 2 stimuli required for detection 50% of time

priming

exposure to one stimulus influences a response to a subsequent stimulus

webers law

stimuli must differ by a % (rather than a constant amount) to be perceived

sensory adaptation

decreased responsiveness to stimuli due to constant stimulation

perceptual set

mental predisposition to perceive one thing and not another

extrasensory perception (ESP)

perception that occurs apart from sensory input; ex. precognition, telepathy, clairvoyance

parapsychology

the study of paranormal phenomenon such as ESP

wavelength (color)

determines color, ex. blue green red

retina

inner surface of eye, this is where processing of information begins

accomodation

lens changes shape to focus near or far objects on retina

rods

detect black, white, gray; peripheral vision

cones

concentrated around fovea, color

optic nerve

carries neural impulses to the brain

blind spot

point where optic nerve leaves eye

fovea

area of greatest visual activity

Young-Helmholtz trichromatic theory

3 types of cones - sensitive to different wavelengths; red, green, blue

Dichromatism

only using 2 types of cones

Monochromatism

only see gray - complete color blindness

Opponent-Process Theory

occurs in Bipolar/Ganglion cells, opposing retinal processes

feature detectors

nerve cells located in the visual cortex that respond to specific features of the stimulus (shape, angle, movement)

parallel processing

processing many aspects of a problem simultaneously

blindsight

people who are blind due to damage to the visual cortex can still respond to visual stimuli without being aware of seeing them

gestalt

an organized whole

figure-ground

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

grouping

grouping what we see into a way that gives it meaning (continuity, proximity, closure)

depth perception

how we see objects in 3D

visual cliff

old enough to crawl, you can use depth perception; portions of depth perception is innate but the entire process is now considered a learned experience

binocular clue

requires 2 eyes

retinal disparity

brain uses retinal images from both eyes to compute distance; greater the disparity the closer the objects

monocular clue

depth cues available to each eye separately

phi phenomenon

an illusion of movement

perceptual constancy

perceiving objects as unchanging, even as illumination or image changes

color constancy

our brain color corrects the world even if it is filtered through a different light

audition

hearing

frequency (hearing)

determines pitch

pitch (hearing)

determined by frequency

cochlea

fluid filled coiled tube in inner ear

sensorineural hearing loss

damage to the cochlea’s receptor cells

conductive hearing loss

mechanical system (eardrum and ossicles)

cochlear implant

help pass sounds to the auditory nerve via electrodes threaded into the cochlea

place theory

we hear different pitches because different sound waves trigger activity at different spots

frequency theory

hairs in basilar membrane vibrate but at different speeds; volley principle

gate-control theory

spinal cord contains a neurological “gate” that blocks or allows pain signals

olfaction

sense of smell; closely connected to memories and emotions

olegustus

fats

kinesthesia

movement of body, muscle memory

vestibular sense

balance, located in inner ear

sensory interaction

our senses work together to create a cohesive perception of the world around us - senses impact each other

embodied cognition

bodily sensations (bottom-up processing) can influence cognitive preferences (top-down processing)

synthesia

a rare condition in which stimulation of one-sensory pathway leads to automatic, involuntary experiences in a second sensory pathway; blending of senses

3 steps of transduction

1. receive sensory stimulation

2. transform stimulation to neural impulses

3. deliver neural information to brain

influences on perception

context/situation, motivation, emotion, perceptual set

cocktail party effect

the ability to focus one’s listening attention on a single talker among a mixture of conversations and background noises

change deafness

failure to notice a change in voices that are speaking

change blindness

people are not always aware of their choices and preferences

optic chiasm

vision is contralateral controlled, this is where they cross

myopia

cant see far

hyperopia

cant see near

amplitude (color)

determines brightness, ex. light blue vs dark blue

perceptual adaption

the ability to adjust to changed sensory input

volleyball principle

neurons take turns firing in rapid succession

tacticle sense

touch

gustation

sense of taste