Psychology- 4 Sensation & Perception

PSY - 101 IU Jim Cuellar

prosopagnosia

face blindness

blindsight

blind in 1 specific field of vision (ex: patient can’t see but can identify movement)

seen wavelengths range

400-700 nm

wavelengths at 400 nm (short)

violet

wavelengths at 700 (long)

red

color is

a product of the brain.

hue

property of wavelengths of light

saturation

purity of lightwave

brightness

perceived intensity of color (amplitude)

ventral pathway

WHAT we see (temporal lobe/ hippocampus)

dorsal pathway

WHERE (locates objects) - (parietal lobe/ sensory perception)

sound is

a product of the brain

frequency

perception of pitch (highness/lowness of a tone) - (hertz)

amplitude

perception of loudness (decibles)

complexity

perception of timbre (quality of a musical sound or voice)

visual form agnosia

the inability to recognize objects by sight

V1

part of the occipital lobe that contains primary visual cortex

pinna

funnels sound

auditory canal

amplifies auditory waves

eardrum

membrane that vibrates in response of sound waves

ossicles (hammer, anvil, stirrup)

pick up eardrum vibrations, amplify sounds, relay soundwaves to the liquid of the inner ear

cochlea

spiral shaped cavity; transductions (vibrations -neurochemical code) of sounds occur

basliar membrane

membrane WITHIN semicircular canal of ear that contains hair cells

• hair cells- embedded in basliar membrane of cochlea

  • they get brittle and damaged as you age

semi-circular canal

fluid filled channels : maintain balance

vestibular sense: maintain balance

auditory nerve

carries neural messages to the brain (thalamus + primary auditory cortex

outter ear

collects sound waves

middle ear

amplifies sounds

inner ear

sounds are transduced into neural messages

cornea

clear membrane that covers the front of the eye

• refracts light

sclera

makes up the cornea and the membrane

• white part of the eye

pupil

the hole formed by the iris (black part)

• lets light into your eye

  • small pupils, clear images

iris

colored part of the eye

• controls the size of the pupil and amount of light reaching the retina

lens

transparent structure behind the pupil

• focuses the image on the retina (changes shape to focus on far to near targets through ACCOMODATION

cones

• color vision

• most located in the center of the retina

• around 6 million

retina

thin membrane lining back of eyeball

• contains rods and cones

fovea

• center of the retnia with all the cones and the BEST vision

• responsible for the SHARPEST vision (acuity)

• responsible for color vision

rods

• detect light and affect color perception

• located in the periphery of the eye

• responsible for night/scoptic vision

• relatively poor acuity (sharp vision)

• around 120 million

sensation

processes by receptors in our sensory organs

• ex: eyes, ears, mouth, nose, skin

perception

processes where info about stimuli is organized, interpreted, and transformed into something meaningful

bottom-up processing

info taken in through your senses (receptor cells)

• data driven processing

top-down processing

converting cell code info to useful info

• conceptually driven process

sensory receptors

cells that collect raw data and transmit it to sensory nerves and the brain

• pain receptors/ smell receptors

sensory adaptation

after brain has determined feelings are NOT a threat

• glasses on your face (not feeling them after a period of time)

transduction

taking information + converting it to a neural signal to be processed by the nervous system

• ex: knowing you smell cookies

afferant nerves

bring info to the brain (sensory neurons)

efferent nerves

send messages away from the brain

absolute threshold

weakest signal

• can be detected 50% of the time

difference threshold

just noticeable difference

• how much of something can be added until a person notices?

Weber’s Law

for each sense the size of a just noticeable difference is a constant proportion of the size of the initial stimulus

photoreception

detection of light, percieved as sight (eyes)

mechanoreception

dection of vibration, percieved as hearing (ears)

Signal Detection Theory

explains how internal and external factors influence our ability to detect weak signals

subliminal stimulation

cant be seen or heard

• product placement (coke and popcorn in movies)

mere-exposure effect

the finding that repeated exposure to a stimulus increases a person’s preference for that stimulus

electromagnetic spectrum

• gamma waves

• x-rays

• ultraviolet

• Infared

• microwaves

• radio waves

visible light range

350-750nm

thalamus

modulates visual signals

length of light waves

determines hues, what people see as color

intensity/ amplitude of light waves

determines brightness

purity of light waves

corresponds to saturation or richness of color

bipolar cells

collect info from rods and cones

-then funnels the collection of raw data to the ganglion cells

ganglion cells

combines, analyzes, and encodes the info from photoreceptors

• final output

accomodation

the lens changes its curvature to focus on distant or close objects (depth)

neural pathways from eye to brain

1) optic nerve exits retina at optic disk

2) optic nerves meet at optic chiasm, split apart, and are sent to the thalamus

3) one set of nerve fibers crossover and projects to the opposite side of the brain

4) another set continues along the same brain side

5) most nerve fibers travel to the thalamus and on to the visual cortex of the occipital lobe

optic chiasm

part of the brain where the optic nerves cross

Trichromatic theory

3 different cones

• provides unique neurochemical code for each color

• (mixed with brightness, amplitude, and wavelength)

• 1st stage

opponent process theory

• visual neurons in the thalamus and the primary visual cortex

• involved in mixing colors: R,G,B,Y, Black cones

  • cells are “tugging” and mixing colors

• 2nd stage

blind spot

obstruction of a visual field

color afterimage

the brain is taking info on wavelengths of light

• painting the color

Hubel and Weisel’s research

(1960s) studied the development of the visual system and ocular dominance columns in kittens at Harvard Medical School

loudness

the intensity (or amplitude) of a sound wave, measured in decibels

pitch

relative highness or lowness of a sound, determined by the frequency of a sound wave

timbre

distinctive quality of a sound, determined by the complexity of the soundwave

decibels

unit of measurement for loudness

hertz

unit of frequency, humans can hear 20-20,000 Hz

frequency theory

basilar membrane vibrates at the same frequency as the sound waves

• discrimination of lower pitches

• fire @ 1000Hz/ 1000 times a second

place theory

different frequencies cause larger vibrations at different locations along the basilar membrane

• discrimination of higher pitches

vestibular sense

balance (can be thrown off by changes in gravity, motion, and position)

• semicircular canal

olfaction

smelling

5 basic tastes

• sweet

• sour

• salty

• bitter

• umami (savory

olfactory bulb

carries info to olfactory cortex of brain

olfactory nerve

• hairs

• receptor cells

• converts chemicals to neurochemicals

pheromones

admitted by humans and ANIMALS

• chemicals found in sweat, armpit hair, blood, semen

• human chemo signals involved in communication emotional states: stress, anxiety, fear

taste receptor cells

covered with grooves, bumps lined with taste buds

• each tastebud contains 50 receptor cells

sweet

energy source

sour

potentially toxic acid; vitamin C

salty

sodium essential to psychological processes

bitter

potential poisons

umami

proteins to grow/ repair tissue

skin

the largest and heaviest organ that contains many kinds of sensory receptors

touch

begins with our skin; houses a variety of receptors

thermoreceptors

senses of hot or cold

pain

unpleasant sensory and emotional experience associated with actual or potential tissue damage

nocioceptors

small sensory fiber in skin, muscles, internal organs

fast pain

immediate pain

slow pain

longterm pain

• developed in the hypothalamus + thalamus (an emotional response)

A delta fibers

myelinated (sharp)

• found in fast pain

C fibers + Substance P

nonmyelinated

• found in slow pain

gate control theory

perception of pain is increased/ decreased by how the brain interprets pain through the interaction of biophysical factors

• ex: a toddler falling and everyone laughing it off (so they believe they are fine)

open pain gate ways

more pain