Sensations & Perception chp 5

Sensation v Perception

Intentional blindness - not noticing something very visible b/c the person was paying attention to something else

• change blindness

• change deafness

selective attention - can only pay attention to one thing at a time

cocktail party effect - in a loud space we are tuned for certain stimulants (ex our name)

stroop effect - if you have two similar stimuli takes you longer to process

diff. between sensation and perception?

sensation - the sensory stimulus

perception - how sensory input is organized, interpreted & consciously experienced

bottom up processing - works to make a whole, building meaning out of the qualities (ex given limited ingredients then having to make a recipe)

top down processing - taking all info we know to apply it to the next situation (ex someone slammed the door, they must be mad)

absolute threshold - minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time

difference threshold - depends on the stimulus intensity

Weber’s Law - the difference threshold is a constant % of the original stimulus

sensory adaptation - diminished sensitivity (neurons stop firing) as a result of constant stimulus

signal detection theory - the intensity of the stimuli + the psychological & physical state of the person contribute to whether or not the person is able to detect the stimuli

Waves & Wavelengths

saccades - our eyes always vibrate a little bit

wavelength - distance from the center line to the top point of the crest or the bottom point of the trough. hue

amplitude - the length of a wave from one peak to the next. brightness/intensity of color

High-frequency sound waves are perceived as high-pitched sounds

low-frequency sound waves are perceived as low-pitched sounds

Vision

optic chiasm - the spot where the optic nerve from each eye merges just below the brain

trichromatic theory - hypothesizes we have three types of cones (red, blue & green) & all the three colors work together to make all the colors on the spectrum

opponent-process theory - if the receptor is drained from red will fire green (same w/ blue/yellow, white/black)

explains after images because if you stare at the color red & look away you will see a green after image

afterimages - (opponent process result) continuation of a visual sensation after removal of the stimulus (ex when you look at the sun, look away & still see its glow)

Auditory

monocular cues - cue that only requires one eye

perceptual constancy - perceiving objects as constant even as illumination & retinal images changes

perceptual set - overarching framework which we interpret stuff

perceptual adaptation - Perceptual systems adapt to their inputs (ex dark theater, then visions adjusts) ONLY SEEING & HEARING

temporal theory - can’t account for the entire range, based theory that hair in ear vibrates to make the noise signal

frequency theory - different portions of the ear sensitive to different frequencies (so diff parts determine what sounds you hear)

cochlear implant - composed of mic, speech processor & electrode array. receives sound → stimulates auditory nerve —> sends to brain

amplitude - height of wave; determines loudness of the sound

frequency - length of the wave; determines pitch

Misc. Senses

gustation - taste

spice is not a taste, spice is pain from your tongue being signaled to the brain

olfaction - smell

smell & taste work together you can’t taste something if you can’t smell it

Gustation & Olfaction are chemical senses because they respond to chemicals instead of energy (sound waves, & light waves)

nociceptor - pain cells

vestibular sac - bubble of air that determines vestibular sense

vestibular sense - balance relative to the ground, where you are in space

kinesthetic sense - perception of body’s movement through space

proprioception - perception of the body’s position

Gestalt - literal meaning: form/pattern. the brain creates a perception that is more than simply the sum of available sensory inputs, and it does so in predictable ways