chapter 3 psych

sensation

activation of the senses when sensory receptors detect a stimulus

perception

the process of organizing and interpreting sensations so we understand what we experience

transduction

changing sensory info such as light or sound into neural impulses that travel to the brain

absolute threshold

the smallest amount of a stimulus that can be detected 50% of the time

difference threshold

just noticable difference

• the smallest change in a stimulus that can be detected 50% of the time

subliminal stimuli

stimuli presented below the level of conscious awareness

sensory adaptation

sensory receptors become less responsive to a constant stimulus over time

cocktail-party effect

focusing on one stimulus while filtering out other distractions, such as hearing your name across a crowded room

visible spectrum

the smalll part of the electromagnetic spectrum that humans can see

cornea

clear outer covering of the eye that protect it and helps focus light

pupil

opening that allows light to enter the eye

iris

colored part of the eye that controls the size of the pupil

lens

focuses light onto the retina by changing shape

accommodation

the lens changing shape to focuses on objects at different distances

retina

light-sensitive layer at the back of the eye where rods and cones are located

transduction

changing light into neural impulses that the brain can interpret

rods

see in black and white

work best tin dim light/night vision

mostly help with peripheral vision

more numerous than cones

cons

see color

work best in bright light/day vision

concentrated in the fovea

allowed detailed vision

fovea

center of the retina where cones are concentrated provides shape, detailed vision

blind spot

spot where the optic nerve leaves the retina has no rods or cone

optic chiasm

point where some visual nerve fibers cross to the oppositite side of the brain

wavelength

determines the color we see

intensity

determines how bright the light appears

saturation

the purity or richness of a color

color- deficient vision (color blindness)

happenes when certain cones are defective, making some colors difuclt to distinguish

trichromatic theory

the retina has 3 types of cones that respond to red, green, and blue light

the brain combines signals from these cones to produce colors we see

opponent-process theory

color vision works through opposing pairs

helps explain afterimages

when one pair is activitated, it inhibits the other

after images

when you look away from a color and briefly see its opposing color

sound waves

vibrations in the air that travel to the ear

frequency

number of sound waves per second, measure in hertz

determines pitch

amplitude

strength of a sound wave

determines loudness

pitch

how high or low a sound is

timbre

the richness or quality of a sound that helps distinguish different sounds

conduction hearing impairment

sound cannot travel proberly through that router or middle ear, often because of damage to the eardrum or ossicles

nerve hearing impairment

damaged to the inner ear, including cochlear hair cells, or the auditory pathways

cochlear implant

a device that helps some people with severe hearing loss by electrically stimulating the auditory nerve

place theory

the location of the hair cells stimulated along the basilicar membrane in the cochlea determines the pitch we hear

frequency theory

the rate at which the basilar membrane vibrated determine the pitch we hear

volley theory

groups of neurons take turns firing to help the brain detect sound drequences that individual neurons cannot follow alone

olfactory receptors

receptor cells that detect odor molecules

olfactory bulb

recieves signals from smell receptors an sends info to the brain

olfactory bulb

receives signals from smell receptors and sends information to the brain

odor molecules

dissolve in the mucus lining near the top of the nasal cavity and stimulate recpector cells

touch

the skin contains different nerve endings that respond to touch pressure and temp

pain receptors

respond to strong or potentially harmful stimuli

gate- control theory

pain signals pass through a gate in the spinal cord before reaching the brain

the gate can allow or limit pain signals

endorphins

natural chemicals produced by the body that can reduce pain by helping close the gate

kinesthetic Sense

sense the position and movement of body parts

vestibular sense

senes balance, movement, and body position

perceptual constancy

the tendency to perceive an object as staying the same even when the image reaching our senses change

size constancy

an object is perceives as the same size even when it looks smalled from far away

shape constancy

an object is percieved as having the same shapee even when viewed from different angles

briightness constancy

an object is perceived as having the same brightness even when the lighting changes

color constancy

we perceive an object as having the same color even when the lighting changes

figure ground

seperating the main object from its background

ex of figure ground

seeing a vase or 2 faces in the same picture

proximity

objects close together are perceives as belonging to the same group

similarity

objects that look the alike are percieved as belonging together

closure

the brain fills in missing parts to see a complete object

ex of closure

recognizing a circle even when the parts of its outline are missing

continuity

we tend to perceive lines and partters as contininung smoothly

common region

objects inside the same enclosed area are percieved as belonging together

contiguity

things that occurs close together in time or space tend to be percieved as related

ex of contiguity

assuming a sound and an action are connected when they happen at the same time

depth perception

the ability to see the world in 3 dimensons and judge distance

monocular cues

depth cues that can be used with one eye binocular cues

dpeth cues that require both eyes

Interposition

An object blocking another object appears closer.

linear perspective

Parallel lines appear to come together in the distance.

realtive size

Smaller-looking objects are usually perceived as farther away if the objects are known to be similar in size.

motion parallax

When you move, nearby objects seem to move faster than distant objects.

Müller-Lyer illusion

Two lines of equal length can appear different in length because of the direction of the arrow-like ends.

Motion illusion

We perceive movement even though the object or image is actually still.

Telepathy

Claiming to read another person's thoughts.

Clairvoyance

Claiming to know about events or things without using the usual senses.

Precognition

Claiming to know about future events before they happen.

Top-Down Processing

• Using past experiences, expectations, and context to interpret sensory information.

• The brain uses what it already knows to fill in missing information.

example of top down processing

Reading a sentence even when some letters are missing.

Bottom-Up Processing

• Building a perception by analyzing the individual details of a stimulus.

• Starts with basic sensory information and combines the details to recognize the whole object.

exmaple of bottom up processing

Seeing a new object and using its shape, color, and features to figure out what it is.

falase positive

detecting a stimulus that in not actually present

fasle negative

failing to detect a stimulus that is actually present

Weber’s Law

• The amount of change needed to notice a difference depends on the original intensity of the stimulus.

• A stronger stimulus generally requires a larger change for the difference to be noticed.

• Related to the difference threshold, also called the just noticeable difference (JND).

Change Blindness

• Failing to notice a change in something you are looking at.

• This happens because we do not pay attention to every detail in our visual environment.

example of change blindness

Not noticing that an object in a picture has changed.