Ch. 4 - Sensation and Perception Flashcards
Sensation represents…
data coming in through sensory neurons— process of detecting, converting and transmitting raw sensory data from external to internal
Perception consists of…(3)
the selection, organization, and interpretation of sensory input
What Influences Perception(2)
- Biological
* Psychological
Transduction is the process of…
turning sensory input into neural signal that the brain can use to perceive
Absolute threshold is the..
minimum stimulation to detect a stimulus 50% of the time
Subliminal is something that you…
Has a short/long term affect
something that you detect less than 50% of the time— short term effect
Something with Just noticeable difference has…
minimal change in stimulus that can just barely be detected
Sensory adaptation implies..
decreased sensitivity to an unchanging stimulus so that you are not overwhelmed— selective attention
Vision is…
transforming light into neural signals
Light is the…
form of electromagnetic radiation that travels as a wave moving at the speed of light
Iris is the… that reacts to…(3)
colored muscle that reacts to intensity of light, drugs, emotion (psychological state),
Pupil acts to…
regulates the amount of light that passes into the rear chamber of the eye— regulated by the iris
The Lens is… and is responsible for…
a transparent eye structure that focuses light rays falling on the retina— responsible for focusing the eye (change of shape)
Defects in the lens cause.. (2)
- Nearsightedness
* Farsightedness
Nearsightedness implies that…
close objects are seen clearly but distant objects appear blurry— because the focus of light from distant objects falls a little short of the retina— when light is bent too much or the eyeball is too long
Farsightedness means that…
distant objects are seen clearly but close objects appear blurry— because the focus of light from close objects falls behind the retina— occurs when the eyeball is too short
Retina is the… and acts to…(3)
neural tissue lining the inside back surface of the eye— absorbs light, processes images, and sends visual information to the brain
Optic disk is the… also known as the…
the hole through which the axons that run from the retina to the brain converge and exit the eye— known as the blind spot
Fovea is the…
greatest visual activity is present at this spot
Rods
specialized visual receptors that play a key role in night vision and peripheral vision— 100 times more sensitive than cones to dim light
Dark adaptation is the process…
process in which the eyes become more sensitive to light in low illumination— as time passes you need less and less light to see (complete in 30 min)
Light adaptation is the process…
process in which eyes become less sensitive to light in high illumination
Receptive field of a visual cell is the…
the retinal area that, when stimulated, affects the firing of that cell
Optic chiasma is the… and ensures…
point at which the axons from the inside half of each eye cross over and then project the opposite half of the brain— ensures signals from both eyes go to both hemispheres of the brain
Feature detectors are…
neurons that respond selectively to very specific features of more complex stimuli
Ventral stream process is the…
perception of form and color, details of what objects are
Dorsal stream is the…
perception of motion and depth, where the objects are
Bottom-up processing is the progression from…
progression from individual elements to the whole
Top-down processing is the progression from… which is…(4)
progression from whole to the elements— way more efficient, less work, less time, we avoid work as much as possible
Subtractive color mixing works by…
works by removing some wavelengths of light, leaving less light than was originally there
Additive color mixing implies…
putting more light in the mixture than exists
• Trichromatic theory:
human eye has three types of receptors with differing sensitivities to different wavelengths
• Color blindness:
encompasses a variety of deficiencies in the ability to distinguish among colors— most people are dichromate
dichromats
which theory can account for this
meaning they only have two color receptors (three types- each insensitive to one of the primary colors)
-trichromatic theory
• Complementary colors:
pairs of colors that produce gray undertones when mixed together
• Afterimage:
Which theory cannot account for this
a visual image that persists after a stimulus is removed
trichromatic theory
• Opponent process theory:
pairs of colors: red vs. green, yellow vs. blue, and black vs. white
color perception depends on receptors that make antagonistic responses to three pairs of colors
-can explain why dichromats have a hard time distinguishing colors in these pairs
• Reversible figure:
a drawing that is compatible with two different interpretations that can shift back and forth
• Perceptual set:
readiness to perceive a stimulus in a particular way— if someone told you the picture was of a duck you would see that first
• Unintentional blindness:
involves failure to fully see visual objects or events in a visual display because one’s attention is focused elsewhere
• Change blindness:
a change that you don’t recognize
• Feature analysis:
process of detecting specific elements in visual input and assembling them into a more complex form— you start with lines, edges, and corners and build them into perceptions of squares, stop signs, ice cream cones, etc.
• Gestalt principles of perception:
whole is more than the sum (tend to see only the whole no the parts)—
• Figure and ground:
one way our brains organize information (dividing the two)— you either see two black faces with a white background or a white vase with a black background– can decide which is the background and see two different things
• Perceptual set:
get stuck on one perception and cannot see any other ones, hard to shift from one to the other
• Proximity:
things that are near one another seem to belong together
• Closure:
people often group elements to create a sense of closure or completeness
• Similarity:
tend to group stimuli that are similar— in the photo things of similar darkness are grouped together
• Simplicity:
people tend to group elements that combine to form a good figure
• Continuity:
reflects on people’s tendency to follow whatever direction they’ve been led
• Perceptual hypothesis:
an inference about what form could be responsible for a pattern of sensory stimulation
• Context:
explains why the power of expectations influence typographical errors
• Depth perception:
interpretation of visual clues that indicate how far or near an object is
• Binocular depth cues:
clues about distance based on the differing views of the two eyes
• Retinal disparity:
refers to the fact that objects within 25 feet project images to slightly different locations on the right and left retinas, so the right and left eyes see slightly different views of an object
• Monocular clues:
clues about distance based on the image in either eye alone— the other kind is pictorial depth cues
• Pictorial depth cues:
cues about distance that can be given in a flat picture
• Linear perspective:
depth clue reflecting the fact that lines converge in the distance
• Texture gradients:
details are too small to see when far away
• Relative size:
closer objects appear larger
• Perceptual constancy:
develops between 3 and 5 months old – the size and shape of an object remain the same despite a change in physical orientation/ viewer’s perspective
• Visual illustration:
inexplicable discrepancy between the appearance of a visual stimulus and its physical reality
Muller-Lyer illusion is…
has two identical lines and one has arrow heads pointing out while the other has arrow lines pointing in which gives the illusion that one line is longer than the other
