AP Psych Sensation and Perception

psychophysics

study of how environmental energy cause a change of behavior and emotion

reception

the absorption of environmental stimuli with sensory receptors

transduction

physically converting energy into mental impulses

transmission

process of relaying neural impulses to the brain via sensory neurons

selection

filtering neural impulses in the reticular activating system

coding

organizing stimuli (in thalamus + hippocampus) and relaying filtered stimuli to the cerebral cortex

interpretation

comprehension, analysis, and evaluation = memory

bottom-up processing

"thick slicing" = conventional processing (1 sensation 2 perception)

top-down processing

"thin slicing" = cognitive assumptions that are based upon experiences and memory, based off learned behaviors

what would happen if there were no natural filters to screen sensory stimuli from the environment?

psychosis: inability to comprehend reality of physical environment

sensory reduction

minimizing the amount of energy absorption at the sensory level

sensory adaptation

cognitive filtering when incoming sensory messages within an environment remain constant, desensitization within sensory neurons

Habituation

cognitive filtering when exposed to repeated stimuli over extended periods of time, learning to desensitize due to constant exposure

absolute threshold

the lowest limit of stimulus energy that can be physically detected with +50% accuracy

difference threshold

measurement of a stimulus' lowest amount of detectable change of intensity

weber's law

in order to sense a difference between 2 stimuli of the same form, but of varying levels of intensity, the degree of change must be a proportionate ratio, not a raw amount

signal detection

consciously adjusting thresholds to become sensitive to specific signals in the environment, selecting what signals to pay attention to will accelerate response time

analgesia

the inability to experience physical pain

purposes of pain

biological warning system, learning mechanism to promote avoidance behavior to ensure species survival

nociceptor cells

specialized pain receptor nerve cells, sensory neuron

substance p

connects body - spinal cord - brain

endorphins

releases to brain - spinal cord - body

anatomy of pain

in the somatosensory cortex

gate control theory of pain

blocking the neural pathways distributing substance P and endorphins from body to brain within the spinal cord

anticipatory pain

fear and anxiety preceding physical injury; top-down processing (cognitive assumptions from experience)

phantom pain

false perceptions of pain typically related to body parts that have been amputated; or perceiving pain that has been experienced by other people

wavelength

horizontal distance of a wave (visible light = 380-750nm)

frequency

the number of wavelength cycles that pass through a fixed point per second (as wavelength decreases, frequency increases)

hue

color

low frequency wavelengths

long, slow waves that produce red (min. threshold = 430THz)

infra red waves

Light wave frequencies < 430 THz, too low of frequency for human detection

high frequency wavelengths

short, fast waves that produce violet (max. threshold = 790THz)

ultra violet

light wave frequencies >790 THz, too high of a frequency for human detection

amplitude

the vertical height of a wave, measurement of energy intensity within the wave, provides the brightness of darkness or lightness

saturation

visual field reflecting/absorbing multiple waves of varying lengths, frequencies, and amplitudes = diverse color patterns

low frequency + low amplitude

dark/dull red

high frequency + high amplitude

bright violet

high frequency + low amplitude

dark/dull violet

low frequency + high amplitude

bright red

eye lid

external protective shield that blocks debris and light, cleans and moisturizes the eye

cornea

internal shield that refracts light waves and has the most nerve receptors

pupil

adjustable tunnel through which light enters the eye

iris

colored, donut shaped muscle that regulates the pupil's diameter, sensitive to amplitude of light waves and melanin protects retina

lens

flexible, transparent disc that focuses light waves onto the retina

vitreous humor

clear, gelatin fluid that fills the ocular chamber to preserves the eye's spherical shape

aqueous humor

clear, gelatin fluid between the cornea and iris

retina

projection screen of the lens that transduces light waves into neural impulses and physical energy conversion = rod + cone receptors

rods

=120 million per eye: located in the outer rings of the retina (peripheral vision, twilight vision, shades of gray)

cones

= 6 million per eye: located within inner core of the retina (color detection, acuity)

macula

center of retina that contains the highest concentration of cone photoreceptors

macular degeneration

#1 cause of blindness

fovea

center most place of the macula and the focal point of lens

optic nerve

nerve connecting the retina to the reticular activating system and transmits neural impulses to the brain (RF)

blind spot

optic nerve disc: place of the retina where the optic nerve is attached and there is no rod + cone photoreceptors

sclera

outer membrane of the eye where ocular muscles and blood vessels are attached

how do eyes use "night vision"?

1. iris muscles contract causing the pupil openings to dilate = maximizing the absorption of limited light wave energy

2. Photoreceptor sensitivity transfers from the cone photoreceptor cells to the rod photoreceptor cells

visual accommodation

- ability of the lens to change the contour of its shape to allow focus far and near

- ciliary muscles relax, allowing the lens to stretch for distance visual focus

- ciliary muscles contract, causing the lens to thicken for short range visual focus

presbyopia

"transitional blindness": inability for the lens to accommodate rapidly as it ages and loses flexibility

myopia (nearsightedness)

visual impairment at a distance, image is focused at a point in front of the retina

hyperopia (farsightedness)

inability to focus images at a close range, image is focused beyond the retina

astigmatism

misshaped eye (cornea), creates multiple focal points causing visual impairments

20/20 vision

normal, not "perfect" vision

20/10

better than normal

legal blindness

not a Rx = 20/200 vision or worse w/ corrective lenses

perceptual processing

1. selection

2. coding

3. interpretation

feature dectectors

small areas within the cerebral cortex that allow for the perception/comprehension of specific stimuli information (fusiform gyrus, transverse temporal gyrus, etc.)

slective attention aka the cocktail party phenomenon

perceptual ability to consciously identify and isolate a single stimulus among a complex mixture of environmental information, focusing on what you feel is important and tuning out competing distractions

inattentional blindness

failure to detect features within the environment when trying to maintain concentrated focus of a selected stimulus

change blindness

perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer is unable to notice it

illusions

sensory misperceptions that result when cognitive assumptions and expectations are proven wrong (top down strategies are proved wrong only when sensed bottom up

form perception

Type of top-down processing strategy that quickly provides the perception of an image based upon the relationship between the figure and the ground

figure

natural interest of an image (color, detail, etc.)

ground

recessive backdrop that naturally assists the figure to stand out

figure-ground illusions

misperceptions resulting when distractions between an images figure and ground become blurred

reversible figure illusions

1 picture that contains 2 images depending on what you perceive as the figure and the ground

closure illusions

perceptual tendency to complete or finish and image when the figure and ground are indistinguishable

impossible figure illusions

images with objects impossible to construct or design because of law of physics

perceptual adaptation

top down ability to adjust to images when presented in a distorted, obstructed, or incomplete view

perceptual set illusions

perceptual adaptation illusions resulting when our cognitive assumptions are proven wrong when top down processing an image in a a distorted view compared to when processed bottom up

thatcher effect

perceptual set illusions involving cognitive expectations of normal human facial features

frame of reference perception

our ability to perceive size, shape, color, time, etc. is largely based upon comparison stimuli, values of an image are perceived based upon how they relate to a frame of comparison = "perceptual relativity"

perceptual constancy illusions

Despite having equal (constant) values, the perceived size, shape, color etc., appears to change relative to different Frames of Reference

parallel processing

the ability of the brain to cognitively multitask and process dual functions required by multiple brain structures simultaneously

perceptual interference illusions

disruptions, delays and processing failure resulting from conflicts when processing multiple cognitive tasks simultaneously

the Stroop effect

interference resulting when a singular task requires the use of both cerebral hemispheres simultaneously

the phi penenomenon

perceptual illusion of motion caused when stationary images or impulses of light are presented in alternation rapid succession and unable to be perceived individually

after image illusions

the residual, phantom appearance of an image that temporarily persists after prolonged exposure or because of bold color

how many hues can humans see?

7 million

color deficient vision (color blindness)

genetic defect affecting the sensitivity of cone photoreceptors (sensation), happens to mostly males

dichromatic blindness

abnormalities with the red-green or yellow-blue systems

monochromatic blindness

only see shades of gray

V1 lateral geniculate nucleus (V1 LGN)

feature detector within the visual cortex and responsible for the perception of color

color sensation

retina

ganglion cells

sensory neurons sensitive to specific frequencies for color detection

bipolar cells

sensory neurons that connect photoreceptors (cones) to ganglion cells

cone photoreceptors

rod + cone photoreceptors transduce light waves into neural impulses

opponent process theory of color

Bipolar cells in are responsible for detecting colors in opposite pairs (2 colors per bipolar cell); when sensing frequencies of 1 color for prolonged periods of time, the other color overcompensates and becomes more sensitive

trichromatic theory of color

cone photoreceptors come in 3 varieties and are capable of detecting 3 colors: red, green, blue; each cone system is sensitive to specific light frequencies

depth perception

the ability to gauge approximate size, distance, and relative motion of objects within a 3 dimensional field of space

linear perspective

visual appearance of parallel lines converging as they reach a point in distance, depth cues are based upon relative sizes of objects, perceived as far and near (colors become less vivid, gray)