AP Psychology Unit 4

sensation

passive process of bringing information from the outside world into the body and brain (unconscious)

perception

the active process of selecting, organizing, and interpreting the information brought to the brain by senses (conscious)

bottom-up processing

analysis of the stimulus begins with the sensory receptors and works up to the level of the brain and mind (sensory)

top-down processing

the interpretation of incoming information based on prior knowledge, experiences, and expectations (perception)

-Ex: where's waldo

selective attention

process of discriminating between what is and is not important is influence by motivation, past experience, culture, and biology

-basically ignoring the non important things

cocktail party effect

ability to tune into a single voice despite many conversations in a noisy room

inattentional blindness

the inability to see an object or a person while out attention is directed elsewhere

- Simons and Chabris

subliminal

below one's absolute threshold for conscious awareness

-unconscious awareness

Change Blindness

failing to notice changes in environment when focused on something

Transduction

In sensations, it is the transformation of stimulus energy into neural impulses

Psychophysics

study of the relationship between physical characteristics of stimuli and our psychological experience with them

Gustav Fechner

early German psychologist credited with founding psychophysics

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Sensory System Steps:

1) receive sensory information from our environment
2) Transform that information into energy impulses (transduction)
3) Deliver neural information to our brain

Threshold

the level of stimulation required to trigger a neural impulse

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time

-Ex: see a flame 30 ft away

Subliminal threshold

stimuli below one's absolute threshold for conscious awareness (unconsciously aware)

difference threshold

the minimum amount of stimulus needed to produce a noticeable change (JND)

- the greater the intensity of the stimuli, the more significant the change needed to be perceived

-Ex: change in temp

Weber's law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount) (about 2%)

sensory adaptation (habituation)

over time, we lose sensitivity to a stimulus from repeated exposure

-does not work with vision because eyes constantly move
- Allows us to be attentive to new potentially dangerous situations

signal detection theory

how we detect stimuli (signal) amid stimulation noisea theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise).

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\- Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

perceptual set

perceiving the world in ways that align with our mood, experience, and expectations

- hard to correct it once we have the wrong interpretation
-works with sight, taste, smell, and hearing though top-down processing

Context effects

experience, culture, and environmental factors can affect perception

Schema

a concept or framework that organizes and interprets information

- Basically, your expectations of the world, based on culture and environment
-guides perceptual set

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-injures might hurt more when angry, and hurt less when happy

-motives can make us perceive a needed object as more or less attractive or accessible

Wavelength (frequency)

The distance between two corresponding parts of a wave

- the longer it is, the less often it occurs affecting color perception
-affects color or pitch

Amplitude

Height of a wave

-affects brightness and loudness

Negative after image

the image seen after a portion of the retina is exposed to an intense visual stimulus

- sensory receptors for certain colors get fatigued, allowing complementary colors to predominate the fatigued colors

cornea

The clear tissue that covers the front of the eye, which bends the light towards the eyeball

pupil

the opening of the center of the eye the appears black

iris

colored muscle surrounding the pupil that controls the amount of light entering.

- opens and closes responding to environmental and internal conditions

lens

curved transparent structure that adjust to focus images to the rear of the eye

vitreous humor

jellylike substance found behind the lens in the posterior cavity of the eye that maintains its shape

retina

the light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information

-rear of the eye
- has visual accommodation

visual accomodation

the focused image to the retina appears inverted

accomodation

process of lens changing shapes to focus near or far in the retina

rods

retinal receptors that detect black, white, and gray; necessary for peripheral and night vision

-20x more rods than cones

cones

photoreceptor cells for daylight and color visions

fovea

the central focal point in the retina, around which the eye's cones cluster

bipolar cells

eye neurons that receive information from the retinal cells and distribute information to the ganglion cells

ganglion cells

their axons form the optic nerve

optic nerve

the nerve that carries neural impulses from the eye to the occipital lobe

hue

color that is determined by wavelength of light

- Just color

intensity

amount of energy of light or sound waves; perceived as brightness or loudness

blind spot

the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

feature detectors

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement in the visual cortex

parallel processing

the ability of the brain to do many things at once simultaneously

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color vision

mental construction based on the wavelengths that an object reflects (rather than absorbs)

Trichromatic theory (young-helmholtz)

the theory that the retina contains three different color receptors—red, green, and blue—which, when stimulated in combination, can produce the perception of any color.

-when colors are equally active, we see white or grey

opponent-process theory

the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

-Ex: some cells are stimulated by green and blocked by red; others are stimulated by red and blocked by green

-opponent pairs can't travel together but can travel with other colors like greenish-blue

-focuses on color perception in the brain rather than the eyes

color blindness

genetic condition of a recessive trait caused by deficiency of cones in fovea

David Hubel

Canadian neurophysiologist noted for his studies of the structure and function of the visual cortex; noble prize

-research of feature detectors

- their research of depriving kittens of their vision showed that there's a critical period during which the visual system develops in animals

Torsten Wiesel

neuropsychologist, made discoveries concerning feature detectors; Nobel Prize

- their research of depriving kittens of their vision showed that there's a critical period during which the visual system develops in animals

Gestalt

an organized whole. Gestalt psychologists emphasized the whole image may exceed the sum of its parts.

-generally considered inborn tendencies

figure-ground

seeing an object in front of a background

grouping principles

proximity, similarity, closure, and continuity

proximity

objects that are close to each other ; are perceived as belonging together

similarity

objects that are similar are perceived as belonging together

closure

tending to complete a form when it has gaps

continuity

following whatever direction we are lead

-Ex: smooth edges are more continuous than rigid edges

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After distinguishing the figure from the ground, our brain uses grouping principles to form meaningful images

depth perception

the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

visual cliff

a laboratory device for testing depth perception in infants and young animals

binocular cues

depth cues that depend on the use of two eyes

retinal disparity

a binocular cue that is the difference between the images the eyes perceives because of their different positions

convergance

based on how much the eyes need to move when focusing on an object

- the more convergence that the eyes must use, the more the object is to the middle of the face

- Ex: putting a finger in the middle of your face and your eyes cross

monocular cues

depth cues available to either eye alone

- compares one object to the ones next to it

relative size

if we assume two objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away

interposition

if one object partially blocks our view of another, we perceive it as closer

relative clarity

hazy object seen as more distant

relative height

we perceive objects higher in our field of vision as farther away

relative motion

objects that move faster are perceived to be closer

motion parallax

a depth cue in which the relative movement of elements in a scene gives depth information when the observer moves relative to the scene

- faster = closer
-slower = farther

linear perspective

parallel lines appear to converge more when they are further

light and shadow

objects that appear dimmer are further

color consistency

Perception that the color of an object remains the e same even if the lighting conditions change

size consistency

Tendency for the brain to perceive objects as the same apparent size as the object moves further away

shape consistency

Tendency to see shapes as unchanging regardless of the angle you see it at

Ames illusion

perceptual adaptation

Allows us to learn to deal with new perceptual experiences

Audition

Biological process of which our ears process sound waves

Sound waves

a longitudinal wave consisting of compressions and rarefactions, which travels through a medium

Pinna

Outer ear to catch sound waves

eardrum

Ear canal (auditory canal) > _______ > hammer > anvil > stirrups > cochlea

Cochlea

a coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

Organ of corti

Center part of the cochlea, containing hair cells, canals, and membranes

Cochlea implants

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

Blind spot

the point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there

place theory

Herman vin Helmholtz stated that higher and lower tones excite specific areas of the cochlea's basilar membrane

Frequency theory

suggests that as pitch rises, the entire basilar membrane vibrates at that frequency

volley principle

The theory holding that groups of auditory nerve fibers fire neural impulses in rapid succession, creating volleys of impulses.

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Ear rely on volume and timing to determine where the sound is coming from

-brain can't accurately locate sounds directly above, below, or front of us

skin

largest organ of the body, detects mechanical energy

Pressure and temperature sensing cells

Detect light touch, pressure, pain, cold, and warmth

pain

Serves as a warning system for damage and danger, helping us survive

nociceptors

Stimulates receptors, but can be reduced by drugs like aspirin

Fast pathways

registers localized pain and relays it to the cortex in a fraction of a second

- Ex: burning yourself

Slow pathways

pain information travels through the limbic system, a detour that delays the arrival of information at the cerebral cortex by seconds

- Ex: aches

gate-control theory

the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

- fails to explain phantom and chronic pain

Large nerve fibers

close the pain gate