AP Psych Sensation and Perception

sensation

information we take in using our senses

transduction

conversion of one form of energy to another

perception

how we organize, interpret, and select information

bottom up processing

• senses

• sensory analysis that your senses do to pass info up to the brain for processing

• driven from data 

top down processing

• brain

• constructs perceptions through sensory input

• brain filters through our own personal experiences and expectations to produce sensations

• schema driven from previous experiences

absolute threshold

minimum stimulation needed for awareness 50% of the time (vary by species, individual, and circumstance)

subliminal

stimulation below your absolute threshold

difference threshold

our ability to distinguish between 2 stimuli 50% of the time

sensory adaptation

diminishing sensitivity to odors, sounds, touches over time 

selective attention

the focus of conscious awareness on a particular stimulus

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

when we don’t notice changes in our environment

perceptual set 

a mental predisposition to perceive one thing and not another, set of mental tendencies

context effects

given stimulus may trigger different perceptions based on context 

extrasensory perception

claims to have perception can occur apart from sensory input

sclera

tough outer coat, which is opaque in front, where it bulges out to create a transparent membrane (cornea)

iris

colored muscle surrounding the pupil

pupil

adjustable opening in the center of the eye, regulates amount of light

lens

transparent structure behind the pupil that changes shape to help focus images on the retina (accomadation)

retina

contains rods and cones plus layers of neurons that begin the processing of information, contains bipolar and ganglion cells, connected to optic nerve 

rods

dispersed throughout the retina - black, white, and gray - dim light

cones

clustered at fovea - color vision, bright light

fovea

in the retina - central point of vision

feature detectors 

nerve cells in the occipital lobe that respond to specific features such as edges, lines, angles, etc

face recognition

right temporal lobe → fusiform area 

damage is called prosopagnosia (face blindness)

Young-Helmholtz trichromatic theory

proposed the retina has 3 different types of color receptors (red, green, blue) and all other colors are a combination of those colors

opponent-process theory

proposed two additional color processes: red/green, blue/yellow, and black/white

response to one color inhibits the other

processing occurs in the neural pathways to the thalamus

gestalt 

an organized whole 

grouping

the perceptual tendency to organize stimuli into coherent groups

figure ground relationship

tendency to organize stimuli into objects (figure) that stat stand out from their background (ground)

relationship continually reverses

sometimes the same stimuli can trigger more than one perception

depth perception

ability to see in 3D, allows us to judge dimension

visual capture

refers to the tendency for vision to dominate over other senses

binocular cues

depth cues that rely on the use of two eyes to help judge distance

retinal disparity 

idea that images of an object from two eyes differ 

the closer the object, the larger the difference 

convergence

extent to which the eyes converge inward when looking at an object that the brain keeps track of to measure distance

phi phenomenon

succession of blinking lights creates the illusion of movement

stroboscopic movement

quick, successive, briefly flashed images where movement is seen 

perceptual constancy

perceiving objects as unchanging despite changes in retinal image

perceptual adaptation

ability to adjust to an artificially displaced visual field

sound waves

bands of compressed air that are changed into neural impulses in the ear and sent to the brain for decoding

detect change in air pressure

amplitude

loudness

frequency

pitch

outer ear

visible portion of the ear, channels waves into auditory canal

middle ear

auditory/ear canal

canal to eardrum/tympanic membrane

transmits vibrations to ossicles

inner ear 

semicircular canals and cochlea 

semicircular canals

where sound is amplified 

fluid sends messages to cerebellum about balance

cochlea

receives vibrations from semicircular canals

basilar membrane

sends motion from cochlea to adjacent nerve cells → bending of hair cells

eustachian tube 

links the pharynx to middle ear 

sensoneural hearing loss

nerve deafness

conduction hearing loss

caused by damage to mechanisms that conduct soundwaves

vestibular sense

relies on the semicircular canals in inner ear to maintain balance

place theory

we hear different pitches based on where sounds hit on the cochlea

frequency theory

brain reads pitch by monitoring frequency of neural impulses traveling up auditory nerve 

gate control theory

theory that the spinal cord contains a neurological "gate" that either blocks pain signals or allows them to pass to the brain. The gate is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger nerve fibers or by information coming from the brain.

four skin senses

pressure, warmth, cold, pain

3 responses to pain

biological, psychological, social-cultural

nociceptors 

sensory detectors that detect pain and hurtful sensations

prostaglandins

body produces at sight of injury

acetaminophen

blocks pain message to the brain

opiates 

for mac daddy pain

block messages from brain to spinal cord

taste and smell

2 chemical senses