psyc

Sensation

The process that occurs when special neuron receptor sites in the sense organs are activated, allowing various forms of outside stimuli to become neural signals in the brain

Perception

the methods by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion
ex: blindfold experiment

Transduction

the process of converting outside stimuli into neural activity

Sensory Receptors

specialized neurons stimulated by different kinds of energy

Just a noticeable difference (jnd)

- Difference threshold.
- The smallest difference between two stimuli is detectable 50 percent of the time.
- Ernest Weber

Absolute Threshold

- The lowest level of stimulation that a person can consciously detect is 50 percent of the time the stimulation is present.
- Gustav Fechner (expanded on Weber's work)

Absolute Threshold for Humans

Vision, hearing, smell, taste, and touch.

Subliminal Stimulation

Receiving messages below your absolute threshold for conscious awareness.

Sensory Adaptation

- The tendency of sensory receptor cells to become less responsive to an unchanging stimulus
ex: food becoming less tasty

Light

complicated phenomenon having both the properties of a wave and particles

Color (hue)

- length of waves
- is seen after the waves of light hit objects and bounce back to us at different frequencies.
- is seen because the eyes have different receptors for different wavelengths.

Saturation

- Purity of the color people perceive
-A highly saturated red, for example, would contain only red wavelengths, whereas a less saturated red might contain a mixture of wavelengths

Long waves

red range

short waves

blue range

Brightness

amplitude of the wave (the higher the wave, the brighter)

Cornea

the clear outer covering of the eye behind which is a fluid

aqueous humor

the fluid that nourishes the eye

pupil

-The black circle in the middle of the eye that changes size as the iris muscles ove to cover and uncover the lens
- It gets larger if there is a lack of light if we see something we like, or if we are afraid
- It gets smaller if we see smth we do not like

Iris

the colored circular muscle that opens and closes which controls the amount of light getting into the eye

Lens

-the transparent structure of the eye that focuses light on the retina (back of the eye) where there are receptors
- It acts like a camera lens

Vitreous humor

the liquid that nourishes and gives shape to the eye

Retina

-The back of the eye which contains millions of receptors for light
_contains rods and cones

photoreceptors

neurons that respond to light

Rods

- visual receptors most sensitive to the violet-purple wavelengths; very sensitive for night vision, used for night vision because they respond well to low levels of light
- "Sees" only in black and white
- Packed in the sides of the retina
- Packed in the sides of the retina
- 125 million in the Retina

Cones

- visual receptors that respond during daylight
See color
- Respond best to wavelength in the red range
- Shut off with little or no light
- There are about 6 million cones in the retina
- Located in the center of the retina
- Provide sharpness of vision

Fovea

the central area of the retina; greatest density of photoreceptors

Blind spot

portion of the retina through which the optic nerve exits and where there are no receptors for light waves

Optic nerve

where the nerve cells leave the eye and send info to the brain

Visual accommodation

As a monocular cue of depth perception, the brain's use of information about the changing thickness of the lens of the eye in response to looking at objects that are close or far away

Presbyopia

-lens hardens through age; loses the ability to focus on close objects
-type of visual accommodation

Myopia

-nearsightedness, focal point falls short of the retina
-type of visual accommodation

Hyperopia

-farsightedness, the focal point is behind the retina
-type of visual accommodation

Visual acuity

-Keenness or sharpness of visions
-Measured by the Snellen chart

Trichromatic theory

- theory of color vision that proposes three types of cone: red, blue, green
-All the colors we see are red, blue, or green, or a mixture of red, blue, and green

Opponent-process theory

-The theory of color vision proposes that visual neurons are stimulated by the light of one color and inhibited by the light of another color
-The firing of cones not used while viewing something steadily in order to bring the visual system back in balance
-afterimage

Afterimage

-The image that remains after stimulation of the retina has ended
-Stare at gree for a miniature, look away, and see red; that's because the chemicals that help us see green are used up, and the ones that help us see red take over
-The afterimage of a color is its complementary color
-Ex: American flag experiment

Color blindness

-Inability to see certain colors
- Most common form is the inability to see red or green but can see in the yellow-blue range
- Most common in males
- Truly " color blind" people are rare; they respond to light waves only with rods
- Ishihara Color Test

Pitch

- how high or low a sound is
- Men have a lower pitch than women
- The more cycles per second, the higher the pitch of a sound
- The human ear can hear sound waves that vary from 20 to 20,000 cycles per second

Volume

how loud a sound is

decibels

- measurement for volume
- loudness is determined by the height of sound waves
- decibel levels beyond 130 are extremely painful to the auditory system

Pinna

- the outer ear
- catches the sound waves and funnels them down the auditory canal to the eardrum

eardrum

piece of skin stretched over the entrance to the ear. It vibrates to the sound waves which causes the three bones (hammer, anvil, stirrup) to vibrate in succession

cochlea

snail-shaped unit filled with fluid

basilar membrane

contains hair cells- receptor cells for hearing. These 20,000 cells are the key to hearing. They are tuned to different frequencies. The vibration is then sent to the Auditory Nerve- the cranial nerve that carries sound from the cochlea of the inner ear to the brain for sound to be interpreted.

Place Theory

- theory of pitch that states that different pitches are experienced by the stimulation of hair cells in different locations on the organ of Corti
- Works for moderate to high pitches.

Frequency theory

- theory of pitch that states that pitch is related to the speed of vibrations in the basilar membrane
- The faster the membrane vibrates, the higher the pitch.
Works for low pitches.

Volley Principle

- groups of auditory neurons take turns sending the message to the brain
- Accounts for pitches from 400Hz to 4000Hz.

Hearing Impairment

May be inherited or caused by disease, injury, or old age.

Conductive Hearing Impairment (Conductive hearing loss)

- Hearing loss is caused by damage to the middle ear, thus interfering with the transmission of sound waves to the cochlea.
- Can't hear sounds that are not loud enough.
- Hearing aids can help with the amplification of sound.

Nerve Hearing Impairment (Sensorineural hearing loss)

- Deafness that results from damage to the inner ear (cannot perceive sounds of certain frequencies).
- Can have a cochlea implant if the cochlea is damaged
- Cannot fix auditory nerve damage (from disease or prolonged exposure to loud noises).

Gustation

sense of taste (chemical sense)

Taste Buds

-taste receptor cells
- 10,000 taste buds are replaced every 10-14days
- Chemical receptors on the tongue that decode molecules of food or drinks to identify them

5 basic types of taste

salt, sweet, sour, bitter, Umami

salt

is necessary for survival, the body may crave salt if you are deficient

sweet

sugar is necessary for energy to run the body

Sour and Bitter

serve as protectors because almost all poisons are bitter, and food that has gone bad has a sour taste to it.

Umami

brothy taste

Smell (olfaction)

- Depends on the ability to detect chemicals
- The most animal-like sense of the human senses

Smell Communication

- Smell is important to eating because it gives out information about food
- Smell is important to eating because it gives out information about food
- Animals use smell to communicate sexual interest by sending out pheromones

pheromones

odor chemicals that communicate a message

cutaneous receptors

nerve receptors in the skin

Pressure receptors

can register a pinprick or an ant crawling on the skin

Temperature changes

registers warm and cold

Pain

remains active for hours to record an injury, can fire for hours after a burn or major cut

CIPA (congenital analgesia and congenital insensitivity to pain with anhidrosis)

- Cannot feel pain
- Fear nothing

Phantom limb pan

The person "feels" pain in the missing limb

Gate-Control Theory

pain signals pass through a "gate" (neutral activity) that sends information to the brain to decide if the pain will be experienced greater or lessened

Kinesthetic sense

Location of body parts in relation to each other

Vestibular Sense (Balance)

- Having to do with movement and body position.
- Structures for this are located in the inner ear.

Perception

the method by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion

constancy

holds steady

Size Constancy

the tendency to interpret an object as always being the same size regardless of its distance from the viewer

Shape constancy

the tendency to interpret the shape of an object as constant

Brightness constancy

the tendency to perceive the apparent brightness of an object as the same even when the light condition change

Space constancy

- the ability to keep objects in the environment steady by perceiving either ourselves or outside objects as moving
- ex: driving

Gestalt

the perception of patterns and whole figures

Figure-ground

- the tendency to perceive objects or figures as existing on a background
- Ex: reversible figure- switch back and forth

Proximity

Perceive objects that are close to one another as part of the same grouping

Law of proximity

objects near each other tend to be grouped together

Similarity

perceive things that look similar as being part of the same group

Law of similarity

items that are similar tend to be grouped together

Closure

the tendency to complete figures that are incomplete

Law of closure

objects grouped together are seen as a whole

Continuity

perceive things as simple as possible with a continuous pattern rather than with a complex, broken-up pattern

Law of continuity

lines are seen as following the smoothest path

Depth perception

the ability to perceive the world in three dimensions

Monocular cues

cues for perceiving depth based on one eye only

Linear perspective

parallel lines seem to converge on each other in the distance

Texture gradient

noticing a certain amount of detail depending on how close something is, giving a sense of depth perception

Binocular cues

cues for perceiving depth based on both eyes

Convergence

rotation of the two eyes in their sockets to focus on a single object

Binocular Disparity

each eye sees a slightly different image

Muller-Lyer Illusion

the illusion of line length that is distorted by inward-turning and outward-turning corners on the ends of the lines, causing lines of equal length to appear to be different

Stroboscopic motion

the illusion of motion that occurs when a stationary object is first seen briefly in one location and, following a short, is seen in another location

Phi phenomenon

lights turned on in sequence appear to move

Perceptual set

- perceive things a certain way because of previous experiences or expectations influence them
- Ex. Ames Room Illusion

Inattentional blindness

an individual fails to perceive an unexpected stimulus in plain sight, purely as a result of a lack of attention rather than any vision

Top-down processing

- use of pre-existing knowledge to organize individual features
- Ex. Make a puzzle with a picture of the finished puzzle to look at.

Bottom-up processing

- analysis of the smaller features to build up to a complete perception
- Ex. No picture for the puzzle, start putting together a small section and keep building up to a complete perception.