Sensation and Perception - 1 Flashcards
Weber’s law
the “just noticeable difference” or “difference threshold” is a constant proportion of the original stimulus size
signal detection theory
detection depends on experience, expectations, alertness, etc.
(more likely to notice a door slam outside when waiting on the pizza guy)
sensory adaptation
diminished sensitivity as a result of constant stimulation (“can you feel your underwear”)
sensory habituation
diminished sensitivity due to regular exposure (do you notice the train?)
perceptual set
tendency to see something as part of a group – speeds up signal processing
inattentional blindness
failure to notice something added because you’re so focused on another task (gorilla video)
change blindness
failure to notice a change in the scene (door study – people did not notice when the person they were talking to was replaced with another person)
cocktail party effect
notice your name across the room when its spoken, when you weren’t previously paying attention
cornea
protects the eye
pupil/iris
controls the amount of light entering the eye
lens
focuses light on the retina
retina
contains rods and cones
fovea
area of best vision (cones here)
rods
black/white, dim light
cones
color, bright light (red, green, blue)
bipolar cells
connects rods/cones and ganglion cells
ganglion cells
opponent-processing occurs here
(the human visual system interprets information about color by processing signals from photoreceptor cells in an antagonistic manner)
blind spot
occurs where the optic nerve leaves the eye
feature detectors
specialized cells that see motion, shapes, lines, etc.
located in occipital lobe (experiments by Hubel & Wiesel)
trichromatic
three cones for receiving color (blue, red, green)
explains color blindness – they are missing a cone
opponent process
complementary colors are processed in the ganglion cells – explains why we see an after image
negative afterimage
when you can no longer see the stimulus, you see its complementary color (seeing green after seeing a red apple)
positive afterimage
when you can no longer see the stimulus, you see the color that it really is (seeing red after seeing a red apple)
visual capture
visual system overwhelms all others (nauseous in an IMAX theater – vision trumps vestibular system)
constancies
recognize that objects do not physically change despite changes in sensory input (size, shape, brightness)
Phi Phenomenon
adjacent lights blink on/off in succession – looks like movement (traffic signs with arrows)
stroboscopic movement
motion produced by a rapid succession of lightly varying images (animations)
monocular clues
how we form a 3D image from a 2D image
interposition
overlapping images appear closer
(monocular clue)
relative size
2 objects that are usually similar in size, the smaller one is further away
(monocular clue)
relative clarity
hazy objects appear further away
(monocular clue)
texture gradient
coarser objects appear further away
(monocular clue)
relative height
things higher in our field of vision look further away
(monocular clue)
linear perspective
parallel lines converge with distance (think railroad tracks)
(monocular clue)
motion parallax
closer objects appear to move faster than objects that are farther
(monocular clue)
binocular clues
how both eyes make up a 3D image
retinal desparity
image is cast slightly different on each retina, location of image helps us determine depth
(binocular clue)
convergence
eyes strain more (looking inward) as objects draw nearer
(binocular clue)
top-down processing
using our prior experience, knowledge, and expectations to interpret sensory information
bottom-up processing
sensory data is interpreted based without reliance on prior knowledge or concepts
