Exam 3 Sensation and Perception Flashcards
What is sensation
The process by which our sensory receptors and nervous system receive and represent stimulus energies from the environment.
What is perception?
The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
How are perception and sensation related
We need to understand what’s going on in the world around us.
What is transduction?
is the process of converting one form of energy into another, in this case converting sensory information into neural impulses that we can interpret.
How is transduction the basis of sensation and perception?
It allows for sensation to become perception
What is sensory adaptation?
If any stimulus input is continuous and unchanging, we will gradually lose awareness of that input.
Why is sensory adaption adaptive to have?
We focus primarily on changes in our environment.
Focusing on changes tends to be the most adaptive response.
What is a perceptual set and how does it affect perception
is a mental prediposition to perceive one thing and not another, especially if the stimulus is ambiguous.
Environmental cues that guide perception.
Our beliefs and expectation (schemas and stereotypes).
How does the amplitude of light waves affect color?
determines the brightness of the light.
How does the wavelength of light waves affect color?
determines the hue of the light.
What is the basic anatomy of the eye
The cornea, lens, retina, optic nerve, and blind spots
retina
contains light sensitive rod and cone cells.
includes the rods, cones and fovea
optic nerve
collects all this sensory information and sends it to the brain to be perceived.
blind spot
The optic connects to the retina at a spot without rods or cones
rods
cells that detect black, white, and gray.
Sensitive to movemnet
Necessary for peripheral and night vision.
cones
cells that detect fine detail and color.
Concentrated near the center of the retina.
Work well in bright light.
fovea
The central focal point in the retina, around which the eye’s cones cluster
optic nerve
transmits neural impulses to the brain.
What happens in the retina to convert light into neural impulses
Light triggers chemical changes in the rods and cones.
These changes activate the bipolar cells.
Bipolar cells activate ganglion cells of the optic nerve.
The optic nerve transmits neural impulses to the brain.
What is the visual pathway
Where ganglion axons of the optic nerve cross over at the optic chiasm.
What are some stops on the visual pathway (thalamus, visual cortex)?
After the cross over, They then synapse with neurons in the thalamus.
Neurons then relay information to the visual cortex.
What is parallel processing and why is it important for perception?
To perceive an object, we need information about its color, form, motion, and depth.
The brain delegates the work of processing these facets of perception to different parts of the brain.
After taking a scene apart, the brain integrates these subdimensions into the perceived image.
What are the specific jobs of rods in the retina?
are in the periphery of the retina and respond to black/grey/white in dim light.
What are the specific jobs of cones in the retina?
are in the center of the retina and respond to colors and details in bright lights
What is the Young-Helmholtz Trichromatic Theory of color?
The retina’s red, green, and blue cones respond in varying degrees to different color stimuli.
All the colors we see depend on different combinations of three cones being activated.
What is Hering’s Opponent Process Theory of color?
Colors work in opposition to each other.
When you stare at a color for too long, the opponent cells on that part of the retina get fatigued or bored with that color.
When you switch to seeing white, you’re seeing all colors but the fatigued cell isn’t ready so the opposing color takes over.
What causes color blindness
One or more of the color cone cells are absent, not working, or detect a different color than normal.
Types of color blindness
Complete color blindness.
- No working cones in the retina.
Red-green color blindness.
Blue-yellow color blindness.
What is feature detection?
nerve cells in the brain respond to specific features of the stimulus, such as its shape, angle, or movement.
What are feature detectors?
individual neurons or groups of neurons which code for perceptually significant stimuli.
How do we perceive faces?
fusiform face area in the right temporal lobe helps us recognise faces
What is prosopagnosia?
a neurological disorder characterized by the inability to recognize faces
What is the Gestalt approach to visual perception
to organize sensations into perception
People tend to organize pieces of information into an organized whole
What is figure-ground perception, and why is it important?
We automatically sort our visual information to identify what is in the foreground (figures) and what is in the background (ground).
most fundamental ways we process a visual scene
What cues help figure-ground perception?
Blurriness = background.
Larger = closer (figure).
High contrast can be used.
Isolated objects are likely figure.
What are the Gestalt principles for grouping
simularity, proximity, continuity, and closure
similarity
This principle suggests that we naturally group similar items together based on elements like color, size, or orientation
proximity
The principle of proximity states that objects near each other tend to be viewed as a group relative to objects that are not.
continuity
We will perceive elements arranged on a line or curve as related to each other, while elements that are not on the line or curve are seen as separate
closure
This suggests that elements that form a closed object will be perceived as a group. We will even fill in missing information to create closure and make sense of an object.
What is the visual cliff
a model of a cliff with a “drop-off” area that was actually covered by sturdy glass
how did the visual cliff determine that young children had depth perception?
The children refuesed to cross it
How do binocular cues help us perceive depth?
Each eye presents a slightly differnet view of the scene.
By comparing the two images, the brain can determine depth.
More disparity = closer object.
What are some monocular cues that help us perceive depth?
A depth cue requiring one eye.
Light and shadow, relative motion, relative size, linear perspective, interposition, relative height.
How do we perceive motion?
The brain has regions to detect motion.
Visual cues can also indicate motion.
We can perceive motion when it’s not really present.
What is stroboscopic motion
brain perceives continuous motion in a rapid series of slightly varying images (e.g. movies).
What is the phi phenomenon
An illusion of movement created when two or more adjacent lights blink on and off in quick succession.
What is perceptual constancy, and why do we need it
the relative stability of the apparent value of object properties when the image varies on a person’s retina
What is color constancy
Perceiving familiar objects as having a consistent color, even if changing illumination alters its perceived color.
What is size consisitancy
Perception of objects as having constant size and form even when our distance and the image on our retina varies
How can we use size constancy to create funny pictures?
STand in front of something tall to make it look like your holding it
Why did so many people disagree on the perceived color of “the dress”?
The dress looked one way under one light and another under another and there were no cues to indicate which one so half corrected one way and half corrected another
What are sound waves
compress and expand air molecules, and the ears detect these brief pressure changes.
how do amplitude and frequency affect their perception?
amplitude, which is perceived as differing loudness
frequency, which is experienced as differing pitch.
What happens in the ear when you hear a sound?
Sound waves strike the eardrum, causing it to vibrate.
Tiny bones in the middle ear transmit the vibrations to the cochlea
Ripples in the fluid of the cochlea bend the hair cells lining the surface, triggering impulses in nerve cells.
Axons from these nerve cells transmit a signal to the auditory cortex.
cochlea
a coiled, fluid-filled tube in the inner ear.
How do we locate sounds around us?
Sound waves strike one ear sooner and more intensely than they strike the other ear.
From this information, the brain can compute the sound’s location.
Why is it risky to listen to loud music for long periods of time?
Listening to loud noise for a long time can overwork hair cells in the ear, which can cause these cells to die.
Also loud noise can damage cells and membrances in the cochlea
