Week 7 Readings Flashcards
The physical process during which our sensory organs—those involved with hearing and taste, for example—respond to external (environmental) stimuli is called ______________
sensation
The physical processing of environmental stimuli by the sense organs.
Sensation
Sensation happens when you eat noodles or feel the wind on your face or hear a car horn honking in the distance. During sensation, our sense organs are engaging in ___________, the conversion of one form of energy into another.
transduction
A process in which physical energy converts into neural energy.
Transduction
What is perception?
The psychological process of interpreting sensory information.
What is an absolute threshold in stimulation?
The smallest amount of stimulation needed for detection by a sense.
What is the method called through which we measure absolute thresholds?
Signal detection
What is signal detection?
Method for studying the ability to correctly identify sensory stimuli.
This process involves presenting stimuli of varying intensities to a research participant in order to determine the level at which he or she can reliably detect stimulation in a given sense.
What is the differential threshold?
also known as just noticeable difference, or JND
The differential threshold is the minimum difference in intensity between two stimuli that a person can detect. It is the smallest change in stimulus intensity that can be noticed.
How is the differential threshold similar to the absolute threshold?
Both the differential threshold and the absolute threshold involve the detection of stimuli. The absolute threshold refers to the minimum intensity of a stimulus that can be detected, while the differential threshold refers to the minimum difference in intensity between two stimuli that can be detected.
What experiment can be used to demonstrate the differential threshold?
An experiment using objects of known weight can be used. For example, a person holds a 1 lb (or 1 kg) object, then it is replaced with a heavier one, such as a 2 lb (or 2 kg) object. The person can easily detect the weight difference when the second object is significantly heavier, but it is more difficult to detect smaller differences, such as between 10 and 11 lbs (or 5 and 5.5 kg).
What is Weber’s Law?
Weber’s Law states that the ability to detect differences between two stimuli depends on the proportion of the difference to the original stimulus, rather than the absolute difference. Larger stimuli require greater differences to be noticed compared to smaller stimuli.
States that just noticeable difference is proportional to the magnitude of the initial stimulus.
Define bottom-up processing
Building up to perceptual experience from individual pieces.
Define top-down processing
Experience influencing the perception of stimuli.
What is bottom-up processing?
Bottom-up processing is when we build perception from the individual pieces of stimuli, such as when we encounter something for the first time and use sensory information to form an understanding.
What is top-down processing?
Top-down processing is when past experiences influence how we process new stimuli, using prior knowledge to interpret information more quickly or in a specific way.
How do bottom-up and top-down processing differ in perception?
Bottom-up processing is data-driven and focuses on building up perception from individual stimuli, while top-down processing is influenced by prior knowledge and experiences to interpret new stimuli.
Can you give an example of how bottom-up and top-down processing work in real life?
Bottom-up processing occurs when you hear a band for the first time and build your opinion from the music itself. Top-down processing happens when you hear a new song by a band you love, and your past experience with the band influences your perception of the song.
How does reading illustrate the concepts of bottom-up and top-down processing?
When learning to read, you use bottom-up processing by focusing on individual letters and sounds. Once you become familiar with words, top-down processing allows you to read quickly by recognizing whole words based on prior experience.
What is sensory adaptation?
Sensory adaptation is the process where we stop noticing a constant and unchanging stimulus because our sensory receptors stop responding to it.
(Decrease in sensitivity of a receptor to a stimulus after constant stimulation.)
What role does the pupil play in vision?
The pupil regulates the amount of light entering the eye by contracting in bright light and dilating in dim light.
What happens to light after it enters the pupil?
Light passes through the lens, which focuses the image onto the retina at the back of the eye.
How does the lens help us see clearly?
The lens focuses light to form a clear image on the retina, allowing us to see the object in detail.
What is the retina?
A thin layer of cells at the back of the eye.
What is binocular disparity?
Binocular disparity is the slight difference in the images focused on each retina due to the different locations of our eyes, contributing to our perception of 3D space.
How does binocular vision help us perceive 3D space?
Binocular vision allows us to perceive 3D space by combining the slightly different images from each eye to create depth perception.
What process occurs in the retina?
Light is transduced, or converted into electrical signals, by specialized cells called photoreceptors.
What are the two main types of photoreceptors in the retina?
Rods and cones.
What is the primary function of rods in the retina?
Rods are responsible for vision in dim light conditions, such as during the night.
What is the primary function of cones in the retina?
Cones provide the ability to see color and fine detail in brighter light.
Where are cones most concentrated in the retina?
Cones are most concentrated in the fovea, the central region of focus.
Where are rods more dominant in the retina?
Rods dominate the periphery of the retina.
Why does a dim star in the sky seem to disappear when you look directly at it?
The fovea, where cones are concentrated, doesn’t have enough rods to process the dim light, making the star seem to disappear.
After light is transduced into electrical signals in the retina, through which nerve does the signal travel?
The optic nerve.
Which brain structure does the visual signal pass through after the optic nerve?
The thalamus.
Where in the brain does information about light orientation and movement begin to integrate?
The primary visual cortex.
What is the fusiform face area specialized for?
Processing faces.
What is the extrastriate body area specialized for?
Processing body parts.
What is agnosia?
A condition where a person loses the ability to perceive certain visual stimuli.
What is the ventral visual pathway also called, and what does it process?
It is called the “what” pathway and processes information about object recognition, including faces and body parts.
What is the dorsal visual pathway also called, and what does it process?
It is called the “where” pathway and processes information about location and movement.
What do optical illusions reveal about visual processing?
They provide misleading information to the higher areas of visual processing in the brain.
What is dark adaptation?
Dark adaptation is the process where rods recover after being bleached in bright light, allowing us to see in dim conditions. It takes around 10 minutes.
(Adjustment of eye to low levels of light.)
What causes the delay in night vision when moving from light to dark conditions?
The delay is caused by rods becoming bleached in normal light and needing time to recover.
What is light adaptation?
Light adaptation is when a large number of rods and cones are bleached at once, causing temporary blindness as we adjust to bright light.
(Adjustment of eye to high levels of light.)
How quickly does light adaptation occur compared to dark adaptation?
Light adaptation happens almost instantly, whereas dark adaptation takes longer (around 10 minutes).
How can you turn on a light without losing your night vision?
Use a red light, as this wavelength doesn’t bleach your rods.
What is the trichromatic theory?
Theory proposing color vision as influenced by three different cones responding preferentially to red, green and blue.
What role do cones play in vision?
Cones allow us to see details in normal light conditions and perceive color.
Cones: what colors do they preferentially respond to?
Cones preferentially respond to red, green, and blue.
What is the trichromatic theory of color vision?
Theory proposing color vision as influenced by three different cones responding preferentially to red, green and blue.
What phenomenon does the trichromatic theory fail to explain?
It fails to explain afterimages, such as seeing colors on a white surface after staring at an image for a while.
What is the opponent-process theory of color vision?
The opponent-process theory suggests that retinal ganglion cells respond to pairs of colors (red-green, blue-yellow, black-white) and compute differences between these colors.
Why can’t we see reddish-green or bluish-yellow according to the opponent-process theory?
The retinal ganglion cells compute differences between opposing colors, making it impossible to perceive both colors in the pair simultaneously.
How does the opponent-process theory explain afterimages?
Afterimages occur because the retinal ganglion cells become fatigued from processing one color in a pair, causing us to see the opposing color when we shift our gaze.
What can cause color-deficient vision?
Issues with cones or the retinal ganglion cells involved in color vision can lead to color-deficient vision.
What is audition?
Ability to process auditory stimuli. Also called hearing.
What does the amplitude of a sound wave code for?
The amplitude codes for the loudness of a sound; higher amplitude sound waves result in louder sounds.
How is the pitch of a sound coded?
The pitch is coded by the frequency of the sound wave; higher frequency sounds are higher pitched.
What aspect of sound allows us to distinguish between different sound qualities, like bright and dull sounds?
The quality, or timbre, of a sound is determined by the complexity of the sound wave.
What does the timbre of a sound help us differentiate between?
Timbre helps us tell the difference between natural and synthesized instruments, as well as between bright and dull sounds.
What part of the ear funnels sound waves into the auditory canal?
The pinna, the external part of the ear, funnels sound waves into the auditory canal.
What is the tympanic membrane, and what role does it play in hearing?
The tympanic membrane, or eardrum, is a thin, stretched membrane that vibrates in response to sound waves, helping to amplify them.
What are the three smallest bones in the body, and what are they collectively called?
The malleus (hammer), incus (anvil), and stapes (stirrup) are collectively called the ossicles.
What role do the ossicles play in hearing?
The ossicles amplify sound waves before they enter the fluid-filled cochlea.
What is the cochlea, and what happens there?
The cochlea is a snail-shell-like bone structure that contains auditory hair cells, where sound waves are converted into electrical signals.
What is tonotopic organization in the cochlea?
Tonotopic organization refers to the arrangement of auditory hair cells on the basilar membrane according to the frequency they respond to.
What is the normal range of detectable sound frequencies for humans?
Humans can normally detect sounds between 20 Hz and 20 kHz.
Where are sound waves converted into an electrical message in the ear?
Sound waves are converted into an electrical message inside the cochlea.
What is the auditory canal?
Tube running from the outer ear to the middle ear.
What are the ossicles?
A collection of three small bones in the middle ear that vibrate against the tympanic membrane.
the malleus (hammer), the incus (anvil), and the stapes (stirrup)
After being processed by auditory hair cells, where are electrical signals sent?
Electrical signals are sent through the cochlear nerve (a division of the vestibulocochlear nerve) to the thalamus and then to the primary auditory cortex of the temporal lobe.
What is the primary auditory cortex responsible for?
The primary auditory cortex is involved in processing various features of sound, though its exact role is still being explored.
How is tonotopic organization maintained in the auditory system?
The tonotopic organization of the cochlea is maintained in the primary auditory cortex.
Which nerve transmits the auditory signals from the cochlea to the brain?
The cochlear nerve, which is a division of the vestibulocochlear nerve, transmits auditory signals to the brain.
What is the vestibular system responsible for?
The vestibular system helps with balance and detecting the body’s orientation in space.
What structures make up the vestibular system?
The vestibular system is comprised of three fluid-filled semicircular canals.
They respond to changes in the head’s orientation in space.
Which nerve transmits information from the vestibular system?
The vestibular nerve, a division of the vestibulocochlear nerve, transmits this information.
How does the vestibular system help us maintain focus on an object while in motion?
It sends information to muscles involved in the movement of our eyes, neck, and other body parts to help maintain gaze and balance.
What can disturbances in the vestibular system lead to?
Disturbances can result in balance issues, including vertigo.
What is somatosensation?
Ability to sense touch, pain and temperature.
transduces physical stimuli, such as fuzzy velvet or scalding water, into electrical potentials that can be processed by the brain.
Tactile stimuli—those that are associated with texture—are transduced by special receptors in the skin called __________
mechanoreceptors
What are mechanoreceptors?
Mechanical sensory receptors in the skin that response to tactile stimulation.
After tactile stimuli are converted by mechanoreceptors, where is the information sent for further processing?
Information is sent through the thalamus to the primary somatosensory cortex.
What is a somatotopic map?
Why are some regions of the body represented as larger in the somatotopic map?
A somatotopic map is an organized representation in the primary somatosensory cortex where different regions correspond to specific parts of the body, with sizes based on sensitivity.
Areas with more sensitivity, like the lips and fingertips, are represented as larger, while less sensitive areas like the shoulders or ankles are smaller.
What does the distorted proportions of the human body in the somatotopic map represent?
The distorted proportions represent the varying sensitivity of different body parts, with more sensitive areas shown larger.
Which side of the body is represented in the somatotopic map in the primary somatosensory cortex?
The opposite side of the body is represented in the somatotopic map.
What is the primary somatosensory cortex?
A strip of cerebral tissue just behind the central sulcus engaged in sensory reception of bodily sensations.
