Chapter 3: Sensation and Perception Flashcards
What is sensation?
The activation of the sense organs by a source of physical energy (including our 5 senses – vision, hearing, smell, taste, touch)
What is perception?
The sorting out, interpretation, analysis, and integration of stimuli carried out by the sense organs and brain.
What is the absolute threshold?
The smallest intensity of a stimulus that must be present for it to be detected.
What is difference threshold?
The smallest level of added (or reduced) stimulation required to sense that a change in stimulation has occurred.
What is Weber’s law?
States that a just noticeable difference is a constant proportion of the intensity of an initial stimulus.
What is sensory adaptation?
The adjustment in sensory capacity after prolonged exposure to unchanging stimuli.
What does the ray of light hit first in the eye?
The cornea
What does the cornea do?
A transparent, protective window that refracts light as it passes to focus it more sharply.
What is the pupil?
The dark hole in the centre of the iris which will increase/decrease depending on the amount of light.
What is the iris?
The coloured part of the eye which controls the size of the pupil.
What is the retina?
The retina converts the electromagnetic energy of light to electrical impulses for transmission to the brain – it turns upside down
What are the two kinds of light-sensitive receptors in the retina?
Rods and cones
What are rods?
Thin cylindrical nerve receptor cells that are highly sensitive to light
What are cones?
Cone-shaped, light-sensitive receptor cells that are responsible for sharp focus and colour perception, particularly bright light.
What is the fovea?
The particularly sensitive region of the retina where cones are concentrated.
What do bipolar cells do?
Receive information directly from the rod and cones and communicate that information to the ganglion cells.
What is the ganglion cell?
They collect and summarize visual information, which is then moved out of the back of the eyeball and sent to the brain through a bundle of ganglion axons called the optic nerve.
What creates a blind spot?
The optic nerve passing through the retina as there are no rods or cones in the area.
Where does the octive nerve split?
optic chiasm
What is feature detection?
The fact that some cells are activated only by certain lines with a particular ship, width, or orientation.
What is the trichromatic theory of colour vision?
Suggests that there is 3 kinds of cones in the retina, each which responds primarily to a specific range of wavelengths (responsive to violet-blue, green, and yellow-red).
What is the opponent-process theory of colour vision?
Cone receptor cells that are linked to form three opposing colour pairs, working in opposition with each other. (blue-yellow, red-green, and black white pairings).
What does the outerear (pinna) do?
It acts as a reverse megaphone, designed to collect and bring sound into the internal portion of the ear.
What does the location of the outer ear do?
It helps with sound localization, the process of by which we identify the directions from which a sound is coming.
What is sound?
The movement of air molecules brought about by a source of vibration
Sound in the outer ear is funnelled where?
The auditory canal
What is the eardrum?
The area of the ear that acts like a drum, vibrating when sound waves hit it, vibrating more when the sound is more intense.
What are the parts of the middle ear?
Three bones; hammer, anvil, and the stirrup.
What does the middle ear do?
They transmit vibrations to the oval window, a thin membrane leading to the inner ear and also increase its strength.
What is the inner ear?
The portion if the ear that changes sound vibrations into a form in which they can be transmitted to the brain.
Once the sound enters the inner ear through the oval window, where does it go?
The cochlea, a coiled tube filled with fluid that vibrates in response to sound.
What is inside the cochlea?
The basilar membrane; a structure that runs through the centre of the cochlea, covered in hair cells
What do hair cells do?
They’re bent by the vibrations entering the cochlea which send a neural message to the brain.
What is frequency?
The number of wave cycles that occur in a second, pitch is adjusted either high or low.
What is amplitude?
Feature of the wave pattern that allows us to distinguish between loud and soft sounds.
what is the place theory of hearing?
The theory that different areas of the basilar membrane respond to different frequencies.
What is the frequency theory of hearing?
The theory that the entire basilar membrane acts like a microphone, vibrating as a whole in response to a sound.
What is the semicircular canal?
Three tubes containing fluid that sloshes through them when the head moves, signalling rotational or angular movements of the brain.
What is the otoliths?
Tiny, motion-sensitive crystals in the semicircular canals that senses acceleration, up-and-down motions, as well as the constant pull of gravity.
What is the sense of smell?
Olfaction; permits us to detect more than 10 000 separate smells
What is the sense of taste?
Gustation; receptor cells that respond to 4 basic stimulus qualities: set, sour, salty, and bitter, (and umami?).
What are the skin senses?
Touch, pressure, temperature, and pain. They all play a critical role in survival.
What is the gate-control theory of pain?
The particular nerve receptors in the spinal cord that lead to specific areas of the brain related to pain.
How can these (stimulated) gates be closed? (In the gate-control theory)
- Psychological factors: emotions, interpretations, and previous experience.
- Other impulses which overwhelm nerve pathways relating to pain.
What is the Gestalt Laws of Organization?
A number of important principles that are valid for visual stimuli: closure, proximity, similarity, and simplicity.
What is top-down processing?
Perception guided by higher-level knowledge, experience, expectations, and motivation.
What is bottom-up processing?
The progression of recognizing and processing information rom individual components of a stimuli and moving to the perception of the whole.
What is perceptual constancy?
The phenomenon in which physical objects are perceived as unvarying and consistent despite changes in their appearance. (ie: shape of door changes as it opens, but is still perceived as same door)
What is depth perception?
The ability to view the world in 3-D and perceive distance because we have 2 eyes.
What is binocular disparity?
The difference in the image seen by the left and right eye: the brain integrating two images into one composite view, but also recognizing the difference in images and uses this to estimate the distance of an object.
What is motion parallax?
The change in position of an object on the retina caused by movement of your body relative to the object.
What is relative size?
Two objects being the same size, the one that makes a smaller image on the retina is farther away.
What is texture gradient?
Provides information about distance because the details of things that are far away are less distinct.
What are monocular cues?
Cues that permit us to obtain and sense depth and distance with just one eye; motion parallax, relative size, and texture gradient.
What is apparent movement>
The perception that a stationary object is moving occurring when different areas of the retina are quickly stimulated, leading us to interpret motion.
