Psych Unit 5

Sensation

The detection of environmental stimuli, such as sounds, objects and smells (Data coming in)

Perception

The experience of detecting those environmental stimuli—it refers to how our brains organize and interpret sounds, objects and smells (How we make sense of the data)

Bottom-up processing

Sensory receptors relay information to the brain. The brain interprets this information

Top-down processing

Previous experience and expectations affect the detection and analysis of information from the senses. Explains visual illusions

Energy senses

Vision - light

Hearing - sound waves

Touch - pressure

Chemical senses

Taste and Smell

Gustation

taste

Olfaction

smell

Vestibular

balance; sensing the orientation of your head/body in space

Kinesthetic Sense

Position and movement of the parts of your body in relation to each other

Sensory adaptation

Diminishing sensitivity to an unchanging stimulus

Psychophysics

Methods that measure the strength of a stimulus and the observer’s sensitivity to the stimulusAbsolute Threshold

Absolute Threshold

Minimum stimulus necessary to detect a stimulus half of the time (going from nothing to something)

Just Noticeable Difference (JND)

Minimal change in a stimulus that can just barely be detected (going from something to something)

Weber’s Law

For a difference to be perceptible, two stimuli must differ by a constant proportion, rather than amount

visual brightness

k=1/62

auditory loudness

k=1/11

weight

k=1/30

Transduction

Transform light energy into neural signals (vision)

Wavelength

distance from one peak to the other

Amplitude

height of the wave

Hue

the color experienced

Intensity

determined by the wave’s amplitude

Rods

Function in dim light. Detect black and white vision, but not colors. Necessary for peripheral and twilight vision

Cones

Near center of retina (fovea). Function in bright or day light. Detect fine detail. Enable color perception

Accommodation

The lens changes shape to focus near or far objects on the retina

Feature Detectors

Cells pass info areas in cortex. Areas recognize biologically relevant objects and specialize in response to a specific stimulus

Parallel Processing

Processes color movement, form, and depth simultaneously in different areas. Integrates dimensions of visual info interpreted in different areas of the brain

Trichromatic Theory

Three types of cones sensitive to different wavelengths of light.

Red light – sensitive to long wavelengths.

Green light – sensitive to medium wavelengths.

Blue light – sensitive to short wavelengths.

Colors other than red, green and blue stimulate a combination of cones

The Opponent-process Theory

Divided into 3 sets of color sensitive neurons: red-green, blue-yellow, and black-white. Each color opposes the other. Light waves excite one color pair – inhibit the opposing color

Shape Constancy

An object appears to change shape with the angle of our view.

Change blindness

failure to notice changes in the environment

Inattentional blindness

failure to see visible objects when attention is directed elsewhere

Perceptual Set

Create a “set” for interpreting stimuli that conforms to expectations/preconceptions, influenced by expectations and preconceptions

Subjective Contours

Perception of contours where none actually exist

Figure Ground

Perceiving figures that stand out from the surrounding background (ground)

Phi Phenomenon

The illusion of movement - presenting visual stimuli in rapid succession

Grouping (Gestalt)

Tendency to organize stimuli into coherent groups 

Proximity (Gestalt)

Perceive objects as belonging together when they are close to one another

Similarity (Gestalt)

Tendency to group objects that have similar characteristics

Continuity (Gestalt)

Tendency to perceive stimuli as a unified form when they appear to be a continuous pattern

Closure (Gestalt)

Tendency to group disconnected pieces of information into a meaningful whole *subjective contours

depth perception

Ability to see the world in three dimensions and know how far away an object is – judging distance, “visual cliff”

binocular cues

visual information is taken in by two eyes that enable us a sense of depth perception

retinal disparity

The difference in the images of objects projected onto the retina is used by the brain as a cue to gauge the distance of the objects, nearby = greater

convergence

Turning the eyes inward to focus on a nearby object creates muscular tension that the brain uses as a cue for depth perception

monocular cues

all the ways that a single eye helps you see and process what you're looking at

interposition

Objects that are obscured by other objects are perceived as being farther away

Relative Clarity

Nearby objects are clearer than more distant objects

texture gradient

The details of nearby objects appear to have a coarser/more detailed texture than those of distant objects

relative height

Near objects are low in visual field; more distant are higher up

linear perspective

Objects and the spaces between them look smaller as they become more distant.  Parallel lines appear to converge as they recede into the distance.

shadowing

Shadows can create the appearance of curving surfaces or 3 dimensions, giving the impression of depth

poggendorf illusion

mueller-lyer illusion

ponzo illusions

Sound Waves

changes in air pressure that unfolds over time

decibels(dB)

Measurement unit for sound - volume 

frequency

corresponds to our perception of pitch. Length of the sound wave; perceived as high and low sounds (pitch)

amplitude

corresponds to our perception of loudness. Height or intensity of sound wave; perceived as loud and soft (volume)

complexity

corresponds to our perception of timbre. Perceived as sound quality or resonance.

outer ear

Sound waves are collected 

middle ear

Sound waves are amplified

inner ear

Sound waves are transduced into coded neural messages

pinna

Visible outer ear on either side of your head; helps pinpoint and locate sound

auditory canal

where sound travels to reach the eardrum

eardrum

Tightly stretched membrane that vibrates when hit by sound waves

cochlea

A coiled, bony, fluid-filled tube through which sound waves are transduced (basilar membrane) into nerve impulses 

Semicircular canals

fluid filled channels that help maintain balance by orienting the brain.

Ossicles

Three tiny bones (hammer, anvil, stirrup) that pick up eardrum vibrations, amplify them, and pass them along to the cochlea in the inner ear

Place Theory

sound frequencies stimulate basilar membrane on specific hair cells (places) resulting in perceived pitch.

Frequency Theory

nerve impulses in auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.

Timing method

noting direction of sound by which ear is stimulated first (best with low frequency sounds)

Volume method

noting direction of sound by which ear is stimulated most vigorously (best with high frequency sounds)

Conductive Hearing Loss

Problem transferring sound waves anywhere along the route through the outer or middle ear.  Help- Hearing aids.

Sensorineural Hearing Loss

Damage to inner ear (cochlea, hair cells). Can be by excessive loud sounds, earbuds, concerts   Help- implant

Sweet

energy source

sour

potentially toxic acid

umami

(savoriness) proteins to grow and repair tissue

bitter

potential poisons

salty

sodium essential to physiological processes

touch

pressure, warmth, cold, and pain

Visual Agnosia 

“mind blindness” -- mind is “blind” to what the senses tell it

prosopagnosia

inability to recognize familiar faces (even one’s own)

agnosia

without knowing

Auditory Agnosia 

inability to recognize certain sounds despite unimpaired hearing

Synesthesia

“joined perception.” one sense is simultaneously perceived as if by one or more additional senses

bipolar cells

one of the main retinal interneurons and provide the main pathways from photoreceptors to ganglion cells, i.e. the shortest and most direct pathways between the input and output of visual signals in the retina.

blind spot

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

cornea

eyes clear, protective outer layer, covering the pupil and iris.

pupil

the adjustable opening in the center of the eye through which light enters.

iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.

lens

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

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.

optic nerve

the nerve that carries neural impulses from the eye to the brain.

fovea

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

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.

pitch

a tone’s experienced highness or lowness; depends on frequency.

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus(signal) amid background stimulation(noise). Assumes there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness.

subliminal threshold

the level at which the participant is not aware of the stimulus being presented