unit 3 psychology

sensation and perception

sensation: process of detecting a physical stimulus (everyone senses a sensation)

perception: process of integrating, organizing, and interpreting sensations.

Sensations are a result of...

sensory receptors, unique to each sensory organ.

sensory threshold

the point at which a stimulus is strong enough to make a conscious impact on a person's awareness

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time- 50 percent of the time because it can vary day to day and person to person.

Difference threshold

• the minimum difference between two stimuli required for detection 50 percent of the time

Webbers law

Ability to notice a difference varies depending on its relation to the strength of the original stimulus.

Whether we can detect a change depends on the OG stimulus.

Transduction

• physical energy is converted to a coded neural signal that can be processed by the nervous system.

• Sent from sensory organ to brain by a stimulus activiting receptor cell then sensory organ then to the brain where it is perception.

sensory adaptation

gradual decline in sensitivity to a constant stimulus

subliminal perception/ mere exposure affect

• thought or behavior that is influenced by stimuli that a person cannot consciously report perceiving

• "mere exposure affect" says when people are exposed to a new stimuli, their liking for it will increase

wavelength

the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths differ. only see 1%

How we see

light reflected from the object to your eye passing the cornea, pupil and lens. color of shirt wavelength is reflected and absorbs all other wavelength

Cornea

the transparent outer covering of the eye that directs sunlight

Sclera

white part of the eye that covers the eye except cornea

Pupil

opening in the middle of iris that lets in different amount of light

Iris

colored part of the eye. Contrasts and narrows to control how much light is coming in or out.

Lens

Behind the pupil that actively focuses or bends light as it enters the eye.

accomodation of lens

lenses change shape to focus light directly on the retina.

nearsightedness

Myopia: distant objects appear blurry. Light is focused in front of the retina

Farsightedness

hyperopia: objects near the eye appear blurry because light is focused behind the retina

Presbyopia

farsightedness caused by unflexibility of the lens of the eye, occurring typically in middle and old age.

astigmatism

a condition in which the eye does not focus properly because of uneven curvatures of the cornea

Retina: Cones and rods

• back of the eye that contains receptors for vision.

• Rods: long thin blunt receptors of the eye that are highly sensitive to black and white not color. Responsible for peripheral and night vision.

• cones: short, think, pointed sensory receptors of the eye that detects color, daylight vision,

Rods/ cones react differently to changes in light amount

• rods: take 30 mind- slow

• cones: take 5 min- fast

Fovea

• small area in the center of retina that is composed fully of cones where visual information is most focused

Blind spot

Point where the optic nerve leaves the eye, producing a small gap in the field of vision. Dont notice it because our brain fills the blindspot with information

Bipolar cells --> ganglion cells--> optic nerve--> brain

• information from sensory receptors are collected by bipolar cells

• Bipolar cells then send data to the ganglion cells that analyzes and enconds infromation from the photoreceptros and then transfers it to the brain.

• ganglion cells receives information more effectively from cones.

optic nerve

• made by 1 million axons of ganglion cells- back of eye that carries visual information to the visual cortex of the brain

optic chiasm

Point in the brain where the optic nerve fibers from each eye meet and partly cross over to the opposite side of the brain.

left = right brain

optic chiasm sends signals to the thalamus to the visual cortex

Blind sight

a condition in which a person can respond to a visual stimulus without consciously experiencing it.

contemporary neuroscience

everything in the mind is a product of brain processes

Color

The perceptual experience of different wavelengths of light, involving hue, saturation (purity), and brightness (intensity). Learned perceptual not a fundamental property.

Hue

varies with the wavelength of light: different wavelengths are perceived different colors

saturation

corresponds to the purity of the wavelength: a clor produced by a single wavelength will appear more vivid compared to a mix of wavelengths

brightness

corresponds to the amplitude (or height) of a light wave. higher= brighter

trichromatic theory

• theory that sensation of color results because cones are especially sensitive to red lighting (long wavelength), green lighting (medium wavelength), and blue lighting (short wavelength).

• Given cone will only be very sensitive to one of the three colors

• when other cones other than R, G, or B are shown , it is a combination of the three.

• Explains R/ G, color blindness

opponent-process theory

theory that color vision is the product of opposing pairs of color receptors: red green, blue yello, black white--> when one is stimulated, the other is inhibited.

Explains afterimages: lingering visual impression. If you constantly stare at a color, rods and cones get overstimulated and become desensitized

Both the opponent-process / trichromatic theory are correct

trichromatic: processed in the Ganglion cels before being transmitted along the optic nerve. Retina processing of cones

Opponent- process theory: Ganglions cells respond and encode in terms of opposing pairs. Processed in the thalamus and visual cortex.

sound waves

the physical stimuli that produce our sensory experience of sound

Amplitude (-------) determine how loud something is.

height of soundwaves measured in desibles.

Frequency(-------) determines pitch(-------)

• rate of vibration measured in hertz

• highness of sound

complexity of soundwaves determine (-------)

Timbre: ability to differentiate sounds

soundwave direction of travel in the ear.

soundwaves are collected in the outer ear, amplified in the middle ear, and transduced into neural messages in the inner ear

Outer ear

• pinna: primary function is to catch soundwaves

• eardrum: vibrates when hit by sound waves

Middle ear

stirrup: transmits the amplified vibration to the OVAL WINDOW: seperating the Mid/Inner ear

Three bones: help with the amplification of sound

conduction deafness

hearing loss caused by damage to structures of the middle or inner ear that can be fixed by HEARING AID

Inner ear

• where sound is transduced into neural impulses; consists of the cochlea and semilircular canal

• As oval window vibrates, it is relayed to the cochlea: coiled fluid filled inner ear structure that contains hair cells in the baslier membrane

How is vibration of sound waves converted into neural impulses

• hair cells bend-> stimulates auditory nerve-> thalamus-> auditory cortex in the brain

Nerve deafness

Inner-ear deafness resulting from damage to the cochlea, hair cells, or auditory nerve- cochlear implant

frequency theory

The view that the basilar membrane vibrates at the same frequency as the sound wave

Place theory

The view that different frequencies cause larger vibrations at different locations along the basilar membrane. explains high frequency

smell (olfaction)

molecules in the air inhaled from the nose

olfactory receptor cells

• replaced every 30-60 days- each oder receptor specialized to respond to molecules of a different chemical structure.

• connected to the olfactory bulb: directly connected to olfactory nerve- enlarged ending of the olfactory cortex at the front of the brain where smell is registered.

olfactory tract

• the path along which the olfactory receptors send their electrical messages to the brain.

• temporal lobe: recognition of smells

• Limbic system: emotional response to smells

pheramones

chemosignals that advertize sexual status/ mating/ warning signals

Taste buds

sensory organs in the mouth that contain the receptors for taste

5 basic taste sensations

sweet, sour, salty, bitter, umami

sensory receptors

unevenly distributed throughout the body - more sensory receptors in face than legs

pain

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

• sensory receptors for pain called nociceptors- free nerve endings

Fast/ slow pain systems

fast: myelinated, fast and intense but short

slow: unemylinated- gradually travels

Pacinian corpuscle

: involved in a sense of touch when stimulated with pressure- when stimulated with pressure, it converts the stimulation into neural messages.

gate control theory of pain

The theory that pain is a product of both physiological and psychological factors that cause spinal gates to open and relay patterns of intense stimulation to the brain, which perceives them as pain.

Sensitization

pain occues without any sensory input- can result into chronic pain- pain after healing occurs

Proprioception

sense of body movement and position

vestibular system

three semicircular canals that provide the sense of balance, movement and positino located in the inner ear and connected to the brain by a nerve

bottom-up processing

emphasizes sensory receptors in detecting a stimuli- focuses on the parts of the whole before moving to the whole

top-down processing

emphasizes the observers experience in arriving at meaningful perceptions- whole to part of the patter

Gestalt Psychology

school pf psychology that aintained sensations are actively processed according to consistent perceptual rules- producing whole, perception. Founded by wertheimer.

figure-ground relationship

gestalt principle that sates a perception is automatically sperated into the figure which is the main element of the scene and the ground is the bakcground

figure ground reversal

perception of a single image in 2 different ways

law of pragnaz

perceptual organization will always be as regular, simple, and symmetric as possible

Gestalt Scientists

studied how perception of visual elements can be organized into similarity, continuity, closure, proximity, symmytry.

monocular cues

relative size, overlap, aerial, texture gradient, linear perspective, motion parallax

relative size

a monocular cue for perceiving depth; the smaller an object is, the farther away it is.

overlap

When one object partially blocks or obscures the view of another object, the partially blocked object is perceived as being farther away

aerial

far- away objects seem blurry by the atmosphere