Chapter 4 & 5

sensation

the stimulation of those cells::perception, bringing to make sense of those cells

nervous system communicates by::neural messages

Transduction::converting one form of energy into another form (neural messages)

senses::sensory receptors

hearing, sight, smell, specialized receptors is to take physical energy to convert into neural impulses

sensory pathways::for each of our senses theres a bundle of neurons carry info from the sense organs to the bra

Thresholds

absolute threshold::smallest amount of stimulation that is necessary for a sense to be detected

difference threshold::represents smallest amount that a stimulus has to change in order for us to notice

Webers Law::the size of the JND is proportional to the intensity of the stimulus

the JND is large::high intensity, small = low intensity

**signal detection theory::**sensation depends of characteristic of the stimulus, background info, and detector

stimulus event > neural activity > comparison with personal standard > action (or no action)

**senses (alike and difference)::**from the parietal lobes

eye anatomy

retina::light sensitive layers at the back of each eyeball

photoreceptors::light sensitive cells in the retina that convert light energy to neural impulses

rods::sensitive to light/ not to colors

cones::sensitive to colors but not dim light, distinguish fine detail

fovea::sharpest vision in the retina.cones sit here

optic nerve::bundle of neurons that carries info from the retina to brain

blind spot::no photoreceptors

visual cortex::part of the brain (occipital lobe)

visual issues

hyperopia/farsightedness::difficulty focusing nearby objects::myopia/nearsightedness

difficulty focusing on distant objects

astigmatism(common)::corneal, or lens defect that causes some areas of vision to be out of focus

presbyopia::farsightedness caused by aging

how the visual system creates color and brightness

wavelength::color

intensity(amplitude)::brightness

electromagnetic spectrum::entire range of electromagnetic energy; includes radio waves, x-rays, microwaves

trichromatic theory::based on three different cone receptors, explains initial stages of color sensation

opponent-process theory::based on bipolar cells colors in complementary pairs, explains afterimages

afterimages::sensations that linger after the stimulus is removed

color blindness::vision disorder that prevents an individual from discriminating

The Physics of Sound

frequency::number of cycles completed by a wave in a given amount of time

amplitude::physical strength of a wave, audio wavelengths

tympanic membrane::the eardrum

cochlea::where sound waves are transduced

auditory cortex::portion of the temporal lobe that processes sound

pitch::produced by the frequency of sound wave

loudness:: produced by the amplitude(intensity) of the sound wave

timbre::quality of a sound wave that derives from the waves complexity

conduction deafness::poor transfer of sounds from tympanic membrane to inner ear, compensates with amplifier

nerve deafness::caused by damage to hair cells or auditory nerve, hearing aids cannot help since they cant reach the brain

cochlear implant::electronic device that stimulates auditory nerves

stimulation deafness:: damage caused by exposing hair cells to excessively loud sounds

vestibular sense::sense of body orientation with respect to gravity, receptors in semicircular canals

kinesthetic sense::sense of body perception and movement of body parts relative to each other, receptors in joints, muscles, and tendons

olfaction::sense of smell

olfactory bulbs::brain sites of olfactory processing

pheromones::chemical signals released by organisms to communicate with other members of the species

gustation::the sense of taste

taste buds::receptors for taste (upper tongue)

what is the taste bud cell?::gustatory cell

what is inside the papillae?::the taste bud

What is the purpose of skin?::The skin protects against surface injury, holds in bodily fluid, and helps regulate body temperature (touch, warmth, cold, texture, pain)

nociceptors(nerve cells)::senses pain/unpleasant stimuli, affected by mood & expectation

phantom limb::an amputee feels sensations coming from missing the body part, due to the brain generating sensation

gate control theory::explains pain control, involves special interneurons that open or closes the pain pathway running up the spinal cord toward the brain

aspirin::interferes with chemical signal

morphine::suppresses pain messages

placebo::mock drug

placebo effect::change effect caused by the belief that one is taking a real drug

What is the relationship between perception and *sensation::*perception brings meaning to sensation; therefore perception produces an interpretation of the external world, not a perfect representation of it.

percept::meaningful product of a perception

feature detectors::cells in the cortex that specialize in detection of specific stimulus features

binding problem::unsolved mystery concerning the processes used by the brain to combine many aspects of sensation into a single percept

bottom-up processing::analysis that emphasizes characteristics of the stimulus

top-down processing::emphasizes the perceivers expectations, memories, and cognitive factors

Perceptual Constancies::ability to recognize the same object under different conditions, such as changes in illumination, distance or location (color, size, shape)

illusions::incorrect experience of a stimulus pattern; shared by others in the same perceptual environment

gesalt psychology::states that much perception is shaped by innate factors built into the brain

figure::part of a pattern that commands attention

ground::part of a pattern that does not command attention; the background

Subjective Contours::Boundaries that are perceived but do not appear in the stimulus pattern

Closure::tendency to fill in gaps in figures and see incomplete figures as complete