The Nature of Sensory Processes (Chapter 3)

Sensation

The experience of stimulation of the body's senses (you experiencing sensations)

Perception

The process by which the brain organizes and interprets sensory information or sensations

Figure

objects perceived to stand apart from background

Ground

background against which a figure appears

Gestalt Psychology

the whole is more than the sum of its parts

Top-down Processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

Bottom-up Processing

Analysis of the stimulus begins with the sense receptors and works up to the level of the brain and mind.

Psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

Example:light-brightness, sound-volume, pressure-weight, taste-sweetness

Absolute Threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time (all senses)

Sensory threshold

the dividing lines where your body starts or stops noticing a physical stimulus

Sensory Thresholds (examples)

Vision: A single candle flame from 30 miles on a dark, clear night

Hearing: The tick of a watch from 20 feet in total quiet

Smell: 1 drop of perfume in a 3-room apartment

Touch: The wing of a bee on your cheek, dropped from 1 cm

Taste: 1 tsp. Sugar in 2 gal. water

Difference Threshold

minimum difference between two stimuli required for detection 50% of the time (just noticeable difference (JND)) Example: hearing test

Subliminal Threshold

When stimuli are below one's absolute threshold for conscious awareness.

Signal Detection Theory (SDT)

Predicts how and when we detect the presence of a faint stimulus (signal) amid background stimuli (other stimulation). (assumes that there is no single absolute threshold) (all senses)

Signal Detection Theory Depends Partly on Persons

experience (practice)

expectations

motivation

level of fatigue; stressors (emotional, environmental etc.)

Example: Baseball player/ batter, wide receiver, video gamers, military, police officer, how fast you can hear an ambulance w (leads to decision making)

SIgnal Detection Theory Matrix

hit, miss, correct rejection, false alarm

Example: Firefighter

Weber's Law

to perceive as different, two stimuli must differ by a constant minimum percentage

Light-8%

Weight-2%

Tone-3%

Example: card with quarter vs textbook with quarter

Sensory adaptation

diminished sensitivity as a consequence of constant stimulation (applies to all of our senses)

Examples: Jewelry, Keys/Phone in Pocket, Glasses

Transduction

In sensation, the transformation of stimulus energy into neural impulses (scientific process of going from sensation to perception) From Sensation to Perception

Vision

Turning stimulus (what you see) into neural impulse being sent to occipital lobe for processing.

Phototransduction

Conversion of light energy into neural impulses that the brain can understand.

What are the Spectrums of

ELECTROMAGNETIC ENERGY? (color and size)

the shorter waves of blue-violet light to the longer waves of red light.

Light characteristics

Wavelength (hue/color)

Intensity (brightness)

Saturation (purity)

Wavelength

is the distance from the peak of one wave to the peak of the next.

Hue (color

is the dimension of color determined by the wavelength of the light.

Intensity

Amount of energy in a wave determined by the amplitude. It is related to perceived brightness.

how is frequency meassured

by the number of wave peaks moving past a given point in a certain amount of time. Therefore: High Frequency = short wavelength (lots of wave past a given point)

Cornea

Transparent tissue where light enters the eye.

Pupil

Opening in eye which light passes through.

Iris

Muscle that expands and contracts to change the size of the opening (pupil) for light. Colored part of eye.

Lens

Transparent structure behind the pupil that changes shape to focus images on the retina.

ACCOMODATION TAKES PLACE HERE!

Retina

Contains sensory receptors that process visual information and sends it to the brain.

70% of all of our sensory receptors are located here!

Fovea

Visual "acuity" happens here. Sharpness/ Details...due to cluster of CONES.

Optic Nerve

Carries neural impulses from the eye to the brain.

Rods

Receptor cells used for night vision

Cones

Receptor cells used for color vision

Blind Spot

Point where the optic nerve leaves the eye because there are no receptor cells located there.

Accommodation

The process by which the eye's lens changes shape to help focus near or far objects on the retina.

Nearsightedness

A condition in which nearby objects are seen more clearly than distant objects.

Farsightedness

A condition in which faraway objects are seen more clearly than near objects.

Bipolar cells

receive messages from photoreceptors and transmit them to ganglion cells, which are for the optic nerve

Optic nerves

connect to the thalamus in the middle of the brain, and the thalamus connects to the visual cortex.

Retinal ganglion cells and thalamic neurons

break down visual stimuli into small components and have receptive fields with

center-surround organization.

parallel processing

Processing of several aspects of the stimulus simultaneously

Trichromatic theory

based on behavioral experiments, Young & Helmholtz suggested that the retina should contain three receptors that are sensitive to red, blue and green colors

MacNichol, Wald and Brown

measured directly the absorption spectra of visual pigments of single cones obtained from the retinas of humans.

Hering proposed that

we process four primary colors combined in pairs of red-green, blue-yellow, and black-white.

Outer Ear

Pinna. Collects sounds.

Middle Ear

Chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window.

Inner Ear

Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

anvil

(also called the incus) a tiny bone that passes vibrations from the hammer to the stirrup.

cochlea

a spiral-shaped, fluid-filled inner ear structure; it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form.

eardrum

(also called the tympanic membrane) a thin membrane that vibrates when sound waves reach it.

Eustachian tube

a tube that connects the middle ear to the back of the nose; it equalizes the pressure between the middle ear and the air outside. When you "pop" your ears as you change altitude (going up a mountain or in an airplane), you are equalizing the air pressure in your middle ear.

hammer

(also called the malleus) a tiny bone that passes vibrations from the eardrum to the anvil.

nerves

these carry electro-chemical signals from the inner ear (the cochlea) to the brain.

outer ear canal

the tube through which sound travels to the eardrum.

pinna

(also called the auricle) the visible part of the outer ear. It collects sound and directs it into the outer ear canal

semicircular canals

three loops of fluid-filled tubes that are attached to the cochlea in the inner ear. They help us maintain our sense of balance.

stirrup

(also called the stapes) a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the smallest bone in the human body (it is 0.25 to 0.33 cm long).

Acoustic transduction

Conversion of sound waves into neural impulses in the hair cells of the inner ear.

place theory

the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated

Frequency Theory

the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch

Volley theory

states that groups of neurons of the auditory system respond to a sound by firing action potentials slightly out of phase with one another so that when combined (frequency/pitch)

Frequency (pitch)

The dimension of frequency determined by the wavelength of sound.

Intensity (Loudness)

Amount of energy in a wave, determined by the amplitude, relates to the perceived loudness.

Quality (Timbre)

Characteristics of sound from a zither and a guitar allows the ear to distinguish between the two.

Conduction Hearing Loss

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea

sensorineural Hearing Loss

Hearing loss caused by damage to the cochlea's receptor cells (CILIA) or to the auditory nerve, OR BOTH - also called nerve deafness

Smell is also called ________

olfaction

Anosmia

inability to smell

transduction smell

Smell comes in through the nose and hits the receptor cells. Messages are then sent to the olfactory nerve. That transfers messages to the olfactory bulb. From there it goes to the temporal lobe in the limbic system.

Pheromones

odor molecules => sense of attraction

Taste is also called ______

GUSTATION

Sensory interaction

the principle that one sense may influence another

Cross Adaptation

brushing your teeth and then drinking orange juice!

WARM + COLD =

PRESSURE + COLD =

PRESSURE + PAIN =

PRESSURE + PRESSURE =

HOT

WET

ITCH

TICKLE

pain

The body's way of telling you something is wrong

Pain control

distracting thoughts is an effective way to increase pain tolerance = placebo effect

Gate Control Theory

Spinal cord contains a neurological "gate" that blocks or allows pain signals. Melzack & WALL

Opened By: Pain signals traveling up small nerve fibers

Closed By: Activity in the larger fibers or by information coming from the brain

Phantom Limbs

the brain can misinterpret the spontaneous central nervous system activity that occurs in the absence of normal sensory input (you can try to reach with a body part that isn't there)

cocktail party effect

=selective attention

filtering in meaningful stimuli, filtering out meaningless info

prosopagnosia

face blindness

sense of touch is a mix of

four distinct skin senses—pressure, warmth, cold, and pain.

DEPTH PERCEPTION

the ability to see objects in 3-D although the images that strike the retina are 2-D; allows us to judge distance

Visual cliff

a laboratory device

for testing depth perception in infants

and young animals

monocular cues

depth cues available to each eye separately

Relative Height

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

Relative Size

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

Interposition

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

Relative Motion

as we move,

objects that are actually stable may

appear to move

Linear perspective

parallel lines appear to meet in the distance

Texture gradient

graduated change in texture (grain) of the visual field; objects with finer, less detailed textures are perceived as more distant

Perceptual Constancy

perceiving objects as unchanging even as illumination and retinal images change (a top-down process)

SHAPE CONSTANCY

we perceive the form

of familiar objects as constant, even

at different angles

SIZE CONSTANCY

we perceive objects as having a constant size, even while our distance from them varies

Figure-Ground

The logo clearly separates the main symbol and typography (figure) from the background.

• Strong contrast helps viewers immediately identify the championship identity without visual confusion.

Closure

Portions of shapes, lettering, or icons may be implied rather than fully outlined.

• Viewers mentally "fill in the gaps," allowing the logo to feel modern and dynamic rather than cluttered.

Continuity (Good Continuation)

Lines, curves, or directional elements guide the eye smoothly across the logo.