chapter 5: sensation and perception Flashcards
the elementary parts of the environment that the brain uses to create meaning
sensations
the processing of stimuli to create a sensory understanding of the world (brain taking in information and combining it with previous knowledge)
perception
the neural processing that starts with the physical message or sensations (early-level analysis that prepares the information for use)
bottom-up processing
when we combine incoming neural massage with our understanding of the world to interpret information in a way that has value
top-down processing
believed that perception was more complicated than assembling messages, but we are born with predisposed ways of organizing information so that it has utility
Gestalt psychologists
outlines the fundamental ways we see the world
Gestalt principles of organization
fundamental way we organize information (prioritizing information)
principle of figure-ground
states that objects that are close to one another will be grouped together
principle of proximity
states that objects that are similar to one another will be grouped together
principle of similarity
states that people tend to perceive whole objects even when part of the information is missing
principle of closure
states that if lines cross each other or are interrupted, we tend to still see the continuously flowing lines
principle of good continuation
states that objects that are moving together will be grouped together
principle of common fate
contains photosensitive receptor cells, at the back of the eye
retina
the outmost, transparent, protective layer of the eye, performs 80% of the focusing of a visual image
cornea
a hole that expands and contracts depending on the environment, it controls the amount of light that reaches the retina
pupil
eye colour, controls the size of the pupil with the band of muscles attached it to
iris
flexible piece of tissue layered like an onion, helps refract light and bring the object into focus on the retina
it elongates when the object is far and rounder and thicker when the object is close
lens
shortsightedness, meaning longer eyes than average, lens focuses the image before it reaches the retina so when it arrives at the photoreceptors, the image is no longer clear
myopia
where light is transduced into cellular activity
photoreceptors
responsive to low levels of light (night vision), respond to the amount of light but not the quality of the light, helps compile early processing about locations of objects and the location of motion in the environment
rods
responsive to bright lighting conditions, responsible for communicating information about acuity and colour, the only cells that communicated about the wavelength (colour) of an object
cones
a dense cluster of 6 million cones, no rods
fovea
occurs as rods and cones adapt to change in light
dark adaptation
upside down, only has the centre in focus (possessed by high-acuity, colour-sensitive cones) and peripheral more blurry and black and white (possessed by the rods)
retinal image
receive messages from 50 rods then add together the experience of photoreceptors and send a single message to the magno ganglion cell
diffuse bipolar cells
receive input from only one cone which is then sent to only a single parvo ganglion cell
midget bipolar cells
Parvo or P-cells (think petite), receive information from the midget bipolar cells, colour processing, make up 70% of the ganglion cells in the retina, send to the brain about qualities of colour and detail
small ganglion cell
Magno or M-cells (think massive), receive information from the diffuse bipolar cells, processing low levels of light, send information about motion and visual stimuli in the periphery
large ganglion cells
ganglion cells only responds to specific portion of the eye or when specific cells are active, organized in a centre-surround fashion
receptive field
made up of axons of both M- and P-cells that enters the brain
optic nerve
a spot on the retina that has no photoreceptors, where axons of M- and P- cells leave to send message to the brain (not noticed because brain fills in the gap)
blind spot
an x-shaped structure where optic nerves from each eye cross before the message is sent to the thalamus
optic chiasm
six-layered portion of the thalamus that processes and organizes visual information, deals with information from M- and P- cells
lateral geniculate nucleus (LGN)
located in the occipital lobe where important features of the visual world are assembled and identified
visual striate cortex (VC)
neuron maintains a spatial organization as it is processed in both the LGN and the striate cortex
retinotopic organization
specialized cells in the VC that respond most actively to specific stimuli
feature detectors
feature-detecting cells in the visual striate cortex that responds to small stationary bars of light oriented at specific angles
simple cell
feature-detecting cells that responds to line of particular orientations that are moving in specific directions
complex cell
“what stream”, takes information from occipital lobe to temporal lobe, where we identify the object
ventral stream
“where stream”, takes information from occipital lobe to parietal lobe, where we identify the location of the object
dorsal stream
the whole process of seeing
cornea -> pupil -> lens -> rods/cones -> diffuse and midget bipolar cells -> small and large ganglion cells -> optic chiasm -> lateral geniculate nucleus of thalamus -> visual cortex
responds to blue
short cones (S-cones)
respond best to greens
medium wavelength cones (M-cones)
respond ti oranges and reds
long wavelength cones (L-cones)
proposes that colour information is identified by comparing the activation of different cones in the retina
trichromatic theory
the cells respond equally to these two wavelengths so the brain cannot perceive the difference
red-green colour blindness
occurs when green cones have red photopigment
deuteranopia
occurs when red cones have green photopigment
protanopia
responds vigorously to one wavelength and reduce firing rate when they receive a signal indicating a different one
red and green / blue and yellow / black and white
P-cells colour pairing
maintained in the LGN of the thalamus, states that cells in the visual pathway increase their activation when receiving information from one kind of cone and decrease their activation a second colour appears (image after effect)
opponent process
cues that only require one eye and can be represented on a two-dimensional canvas (retina)
monocular depth cues
occurs when one image partially blocks the view of a second object, making the blocked object seen as farther away
occulsion
relative height objects closer to the horizon will appear farther away
relative height
two objects are of the equal size but the one further will take up smaller portion of the retina
relative size
uses the assumption of relative size, making the people walking in it to shrink and grow depending on their positions
Ames room
as parallel lines move away from us they seem to converge or come close together
perspective convergence
judging distances based on our knowledge of that object’s size
familiar size
occurs when more distant objects appear hazy and have a slight blue tint because of the air particles, dust, pollution, and water droplets occupying the space in between
atmospheric perspective
cues that require both eyes to make comparison between the images from both eyes
binocular depth cues
the difference between the retinal image that falls on both eyes, as images become farther away, they have a smaller degree of disparity on the retinas
retinal disparity
mechanical energy that requires a medium (air or water) to move through space, which brain interprets as small vibrating air molecules
sound
determined by the rate of vibrations, the higher it is = higher pitch
frequency
perceived as loudness, amplitude of the wave, measured in decibels (dB)
intensity
the external part of the ear, shaped this way to filter the sound into the ear canal toward the tympanic membrane
pinna
the eardrum, the surface transfers energy to the ossicles
tympanic membrane
three smallest unbreakable bones in our body that amplifies the vibration arriving the eardrum and transmits these signals to the oval window of cochlea (malleus, incus, and stapes)
ossicles
transfers vibrations to cochlea
oval window
bony sound processor of the inner ear where it is transduced into the neural language of the brain
cochlea
flexible piece of tissue where the hair cell is located inside the cochlea
basilar membrane
bony chambers connecting to cochlea, fluid moving in each chamber provides directional information to our vestibular system (head rotation and changes in acceleration)
semicircular canals
transduction in the ear
occurs when the vibrations against the oval window cause fluid inside the cochlea to move, pushing cilia (thin fibres) attached to the sensory hair cells, basilar membrane ripple, causing cilia to bend and create an excitatory message to cascade from the ear to the brain via auditory nerve
the whole process of hearing
pinna -> tympanic membrane -> auditory ossicles -> oval window -> basilar membrane -> semicircular canals -> cochlea -> auditory cortex
suggests that we understand pitch because of the location of firing on the basilar membrane
place theory
states that the brain uses information related to the rate of cells firing, the more rapid it is the higher the perception of pitch
frequency theory
auditory cortex located in the temporal lobes
auditory cortex
the portion in the thalamus that evaluates and organized information before sending it to auditory cortex
medial geniculate nucleus
spatial organization of neurons as it is processed in the thalamus and auditory cortex
tonotopic organization
auditory cues that require comparisons from both ears to understand the location of the sound
binaural cues
comparisons made between the arrival time of a sound in each ear
interaural time differences
uses two microphones arranged to record sounds in the approximate location of human ears
binaural recording
the head absorbs a small portion of the sound so the ear closest to the sound will perceive the noise as slightly louder than the second ear
interaural level differences
“earworm”, the experience of an inability to dislodge a song and prevent it from repeating in one’s head
involuntary musical imagery
example of how visual information can be used to help supplement the sounds coming into our ears
McGurk effect
sensory cells in the nose the respond to properties in air molecules that are interpreted as smell and taste
chemoreceptors
the only sense that doesn’t first go through the thalamus
olfaction
detect odorants, humans have 350 types of these receptors, each responding to different ranges of molecules
olfactory receptor neurons
where the olfactory receptors neurons are located
olfactory mucosa
consolidate all the messages from a particular receptor type in the olfactory bulb
glomeruli
five basic tastes
sweet, sour, salty, bitter, and umami
the little bumps on the tongue where taste buds are located
papillae
found over the entire surface of the tongue and give the tongue its fuzzy appearance (doesn’t contain taste buds)
filiform papillae
on the tips and sides of the tongue, look like little mushrooms
fungiform papillae
along the back of the tongue
foliate papillae
on the back of the tongue and are shaped like little mounds
circumvallate papillae
the location of taste-sensitive cells on tongue (taste buds contains 50-100 taste sensitive cells)
taste pore
transduction in taste
chemicals bind to receptor sites on the taste pore, and message is sent through afferent nerves to the brain and stomach
both taste and smell are combined here
orbitofrontal cortex (OFC)
neurons that respond to more than one sense that specialize in determining sensations that occur together
bimodal neurons
receptors cells embedded in the skin that respond to pressure, where information about texture is derived from
mechanoreceptors
mechanoreceptors located close to skin surface that fire continuously when skin is making contact with an object (fine details)
Merkel receptor
mechanoreceptors located close to surface of the skin that fire when skin first encounters the stimulus and when it is removed
Meissner receptor
mechanoreceptors located deeper in the skin that is associated with interpreting the stretching of the skin
Ruffini cylinder
mechanoreceptors located deeper in the skin that feels vibration and texture
Pacinian corpuscle
organizes information from the body
somatosensory cortex
the spatial organization of touch, two adjacent points of contact on the skin are represented by two adjacent points of neural activity on the cortex
somatotopic organization
receptors in skin that is designed to detect changes in temperature
thermoreceptors
detect pain and send a signal to our brain
nociceptors
suggests that impulses that indicate painful stimuli can be blocked in the spinal cord by signals sent from the brain
gate-control theory of pain
respond to damaging and painful stimuli
small diameter fibres (S-fibres)
activated when S-fibres are active, determines the intensity of the perception of pain
transmission cell (T-cell)
send signals to the brain about stimulation that is not painful, inhibits the activation of T-cells, which closes the gate and decreases the perception of pain
large diamater fibres (L-fibres)
congenital insensitivity to pain, a rare condition where the effected is unable to perceive pain and temperature, results from a recessive allele on chromosome 2
congenital analgesia
provides basic understanding of where our body is in space and how to move our bodies to accomplish tasks, relies on touch senses, signals from joints are sent to the somatosensory cortex
kinesthetic sense
our sense of balance, sensory cells located in the cochlea
vestibular sense
psychophysics attempts to evaluate the way the physical experiences of light, sound, and chemicals in our nose are translated into psychological perceptions
psychophysics
the level of intensity required to create a conscious experience (the point where the stimulus is detected)
absolute threshold
those with high hit rates (reports a stimulus when none is present) and high false alarms (with bias that are likely to say a stimulus is present)
liberal response bias
individuals with higher miss rate (says no stimulus when one is present)
conservative bias
the small amount of a particular stimulus required for a difference in magnitude to be detected
difference threshold
states that the ability to notice the difference between two stimuli is proportional to the intensity or size of the stimulus (increased intensity or size = larger difference required)
Weber’s Law
