Sensation and Perception : Vocab

Sensation

Sensation

our sensory receptors receiving info from stimuli in the environment

Perception

our brain organizing and interpreting sensory info, gives us our ability to recognize/categorize/understand

Bottom-Up processing

makes sense of the information (new experiences); younger in life

Top-down processing

our brains construct perceptions based on our experiences and expectations (known experiences); older in life

Selective attention

the focusing of conscious awareness on a particular stimulus.

Selective inattention

failing to see visible objects when our attention is directed elsewhere????

Change blindness

failure to notice changes in the environment

Transduction

the process of converting sensory inputs into neural impulses

Psychophysics

branch of psych that studies relationship between stimuli physical characteristics and its perception (ex. a lights intensity and apparent brightness)

Absolute threshold

how much of a stimulus do we need to detect 50% of the time

Signal detection theory

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

Difference threshold

minimum difference between 2 stimuli in order to be detected 50% of the time

Weber's Law

to perceive a difference between 2 stimuli they must differ by a minimum percentage (light intensity 8%, wight 2%, sound pitch 0.3%)

Sensory adaptation

when we are repeatedly exposed to a stimulus and thus respond less strongly to it

Perceptual set

pre-conceived way of interpreting a stimulus that is usually culturally or socially reinforced (ex. sensor bleep)

Pupil

center of the eye opening, it expands and contracts due to the action of the iris

Iris

colored muscle around the pupil

Lens

lies behind the pupil, focuses the incoming light rays onto the retina through accommodation

Retina

inner surface of the eye, highly sensitive to light; contains rods, cones, and neurons; the image focused on to it is upside down

Accommodation

changing shape in order to focus the object clearly

Rods

receptor cells that detect white, blacks, and greys; ~120million

Cones

receptor cells that detect colors; ~6million

Optic nerve

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

Blind spot

no rods or cones where optic nerve leaves the eye causing a blind spot in our vision

Fovea

the point on the retina where images are focused, the cones cluster around it; the most sensitive area

Feature detectors

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

Parallel processing

the processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving

Young-Helmholtz theory

the cones are sensitive to either red, green, or blue and that combinations of these allow us to see color

Opponent-process theory

says we have three opponent color pairs (red/green, yellow/blue, black/white); color vision comes from neurons being turned on or off by these colors

Gestalt principles

an organized whole; emphasizes our tendency to integrate pieces of info into meaningful wholes

Binocular cues

depth cues that depend on use of both eyes (ex. Retinal Disparity)

Monocular cues

depth cues, available to either eye alone (ex. interposition and linear position)

Phi phenomenon

an illusion of movement created when 2 or more adjacent lights blink on and off in quick succession

Perceptual constancy

perceiving objects as unchanging even as illumination and retinal images change

Perceptual adaptation

in vision, the ability to adjust to an artificially displaced or even inverted visual field

Eardrum

the membrane of the middle ear, which vibrates in response to sound waves

Middle ear

the chamber between the eardrum and cochlea; stirrup, hammer, and anvil; concentrate the vibrations of the eardrum on the cochlea's oval window

Cochlea

a coiled, bony, fluid filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

Sensorineural hearing loss

caused by damage to the cochlea's receptor cells or auditory nerves (ex overexposed to loud sounds)

Conduction hearing loss

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

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 tone

Gate-control theory

the spinal cord contains a neurological gate that blocks pain signals or allows them to pass on to the brain

Kinesthesia

your sense of the position and movement of your body parts

Vestibular sense

the sense of body movement and position including the sense of balance

Sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste

Visual processing pathway

lens -> fovea -> bipolar cells -> optic nerve