Unit 3: Sensation and Perception

Sensation

Sensation

the process which our sensory system receives information from the environment.

Transduction

when sensory information is converted to neural information.

Perception

the process of selecting, organizing, and interpreting sensory information.

Bottom Up Processing

Putting together an image piece by piece; from small parts to the whole picture.

Top Down Processing

looking at the whole picture first then looking at the individual parts. Influence by expectations and experience.

Inattentional Blindness

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

Selective Attention

the focusing of conscious awareness on a particular stimulus.

Change Blindness

failing to notice changes in the evironment.

Absolute Threshold

The minimum stimulation necessary to detect a particular stimulus 50% of the time.

Difference Threshold (Just Noticeable Difference)

the minimum difference between to stimulus required for detection.

Weber’s Law

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

Signal-Detection Theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise) : uses top down processing and expectations

Sensory Adaptation

diminished sensitivity as a consequence of constant stimulation.

Sensory Interaction

how sense interact and influence each othe .

wavelength

the distance from the peak of one light or sound wave to the peak of the next.

Hue

the dimension of color that is determined by the length of wavelength.

Intensity

the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude (height).

cornea

outer transparent covering

Pupil

opening in the center o the ye that lets light in

iris

the colored part that controls the pupil

lens

focuses the image to the retina

retina

nerves that line the inner surface of the eye where transduction occurs.

blind spot

where the optic nerve leaves the eye

optic nerve

carries info to the brain

fovea

area of the retina where vision is clearest

Rods

detect black, white and gray (120 million)

cones

detect fine detail and help process color (6 million). Located near the fovea; not in peripheral vision.

Bipolar Cells

connect the rods/cones to the ganglion cells

Ganglion cells

connect the bipolar cells to the optic nerve

Optic chiasm

where visual information crosses over the other hemisphere

Trichromatic (three-color) Theory

Theory of color vision that says cones are “tuned” to be sensitive to red, green, and glue light. All the colors we see are a combination of these three colors.

Color Deficient Vision

People who lack or have damage in one of the three types of cones

Opponent Processing Theory

The theory that opposing retinal processes enable color vision

Pathway of Vision

Cornea, Pupil, Lens, Retina, Rods/Cones, Bipolar, Ganglion, Optic Never, Thalamus, Occipital Lobe

Audition

the act of hearing

amplitude

determines loudness

Frequency

determines pitch

pinna (outer ear)

directs sound waves down the ear canal to the ear drum

tympanic membrane (ear drum)

vibrates from sound waves and bangs into 3 bones (H,A,S)

Bones of the Middle Ear

Hammer, Anvils, stirrup- swing and bang into each other to pass on the sound, then stirrup hits the cochlea

cochlea

coiled, contains fluid and hair (basilar membrane)

Where transduction occurs

Semicircular canals

filled with fluid; affect our balance

auditory nerve

takes sound information to the thalamus and then on to BOTH temporal lobes

Pathway of Hearing

Pinna, ear canal, tympanic membrane, H.A.S, cochlea, auditory nerve, thalamus, temporal lobe

Place theory

pitch is determined by location of vibration along the cochlea’s membrane

Frequency Theory

pitch is determined by how fast the neural impulse travels up the auditory nerve

Conduction Hearing Loss

damage to the structure of the middle or inner ear. Surgery

Sensorineural Hearing Loss

linked to a deficit in the body’s ability to transmit impulses form the cochlea to the brain.

Touch

Transduction occurs at receptors on the skin, which send the signal to the brain via afferent neurons.

Touch- skin receptors

pressure

warmth

cold

pain

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.

Kinesthesis

the system for sensing the positions of individual body parts. Also called proprioception

Vestibular Sense

The sense of balance

Located in the inner ear

Semicircular canals

Phantom Limb Sensation

Signals are misinterpreted by the CNS due to the lack of other expected signals

Gustation

the sense of taste

Taste Receptors

Sweet, Sour, Salty, Bitter, Umami

Aguesia

Loss of the sense of taste

Olfaction

the sense of smell

Anosmia

Loss of the sense of smell

Perceptual Principles

are short cuts that our brains take to make sense of what we are looking at

Figure-ground

the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)

Grouping

the perceptual tendency to organize stimuli into coherent groups

Proximity (nearness)

Similarity

Continuity

Closure

Perceptual Constancy

Our tendency to perceive objects as stable and unchanging despite changing sensory information

Size constancy

Shape constancy

Color constancy

Figure Detectors

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

Parallel Processing

the processing of several aspects o a problem simultaneously

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 Experiment

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

Monocular Cues

depth perception using only 1 eye (interposition; linear perspective)

Binocular Cues

depth perception that depends on both eyes

Retinal disparity

comparing the images form the 2 retinas to compute distance