Week 7 Flashcards
we have __ __ of our world
subjective experiences
those experiences are created from
physical phenomena that we encounter
psychophysics
the study of how physical stimuli are translated into psychological experience
What was Gustav Fechner particularly interested in
studying strength of stimuli and how we detect/differentiate information from the environment
stimulus
any detectable input from the environment
Fechner and other of the time were particulary interest in
the minimum intensity required for us to detect something
they called this
the Threshold for detection
Threshold
a dividing point between energy levels that do not have a detectable effect
he was also interested in how
different two stimuli had to be in order for us to tell them apart
these are referred to as
noticeable differences
just noticeable differences
the smallest difference in the amount of stimulation that a specific sense can detect
the nervous system codes information from the
environment using neurons and sensory receptors
give an example
cells in your eyes detect light
this information is then transfromed into
a mental representation in the brain through a separate process
we call these two processes
sensation and perception
our organs are capable of
detecting information from our environment
this process is called
sensation
give an example
when light hits the retina in the eye it is detected by cells, this is the sensation of light
there are more than __ senses give an example
6 ( proprioception)
sensation relies on
sensory receptors
sensory receptors (sensory cells)
convert stimuli form the environment into patterns of patterns of electrical signals (action potentials)
sensory neurons
nerve cells that transmit sensory information form the body to the brain and spinal cord
Sensation
The stimulation if sensory organs
some sensory receptors are neurons with
encapsulated or free nerve endings
these are
primary sensory receptors
Primary sensory receptors
Neurons that directly convert a stimulus into electrical signals
in this case the __ itself directlly__ ___ from the ___
in this case the neuron itself directly senses stimuli form the environment
directly conducts __ impulse to __
electrical impulse to CNS
Somatosensation
Detecting pressure form the surface of the skin
Many sensory receptors require a second specialized cell type which are
Secondary receptors
Secondary sensory receptors
non-neuronal cells that first repsons to a stimulus and then communicate it to a nearby neuron
specialized __ that trasmit __ to nearby __ __
specialized cells that transmit information to nearby sensory neurons
the sensory receptor is __ part of the neuron
not
which conducts __ impulse to __
Which conducts electrical impulse to CNS
Example
hair cells (hearing)
in both cases information is sensed from
from the environment by some sensory cell
it is then
converteted to action potentials ( electrical activity) of sensory neurons
from there
it is transmitted to the brain
information detetced form our enivronemnt must also
used by the brain
the brian uses this to create
our conscious experience of the world
the proces of turning sensed information into usable information by the brain is called
perception
Preception
The selection, organization and interpretation of sensory input
Preception is the ___ of our ___ experience of information ___ from the environment
Preception is the creation of our conscious experience of information sensed from the environment
those mental representation are called
percepts
give an example
you can probably imagine and mentally visualize an object you have seen earlier today
Percept
A mental representation of sensory input, forming our concious awareness if the world
when does perception happen
not until information reaches the brain
primary cortices
first create mental experience from sensory information
responsible for
processing patterns of sensory information
so information is __ first and then __
sensed, perceived
perception creates a
mental represenation of information form sensory information
Preception helps us to
Helps us to recognize objects, understand their context and make menaing out of our surroundings, etc
Where does sensation mostly happen
In the periphery
Where does preception happen
In the Brain
what historical perspective neglects this phenomenon
fechners historical threshold perspective
it suggest
that there is actually no single minimum threshold for detecting sounds or other stimuli form the environment
attention capture is affected by
context and importance
this is the basic premise of
signal detection theory
signal detection theory
Proposes that the detection of stimuli involves both decsion process and sensory process, which are influenced by a variety of factors besides signal intensity
it is not only the __ of the stimulus that matters
strength
psychological processes also influence whether or not and how
we detect information from our environment
Sensitivity of sensory systems are __ static
not
Contiunuosuly activating a sensory system will tent to
reduce its sensitivity
give an example
when in the light for a long peirod it is difficult to see if you suddenly turn out the lights
Sensory adaptation
a gradual decline in sensitivity due to prolonged stimulation
light enters from the __ and is focused by the __ onto the __ at the __ back of the eye
light enters from the cornea and is focused by the lens onto the retina at the_ back of the eye
the retina contains
light-sensitive cells called rods and cones
Retina
A layer of photoreceptors cells within the eye that captures incoming light and transmits visual signals along neuronal pathways
what do these cells do
convert light into electrical signals that are sent to the brain
rods
visual recepetors that play a role in night vison and peripheral vison
cones
visual receptors that play a role in daylight and color vison
Visual fields
Are projected to the brain contralaterally
the blind spot
is a small area on the retina where the optic nerve exits the eye
it lacks __ __ so it cannot
it lacks photoreceptor cells so it cannot detect light or form images
visual fields
are projected to the brain contralaterally
__ __ from each eye __ __ to the opposite __ for processing
_visual _ information from each eye crosses over to the opposite hemisphere for processing
Contralateral
Projected to the opposite side of the brain
Ipsilateral
Projected to the same side of the brain
this information crosses over at the __ where the __ __ meet
this information crosses over at the optic chiasm where the optic _nerves- meet
then vision is first proccesed at the
the back of the brain
where is the primary visual cortex located
in the occipital lobes
Dorsal stream
The “Where pathway”
What does it do
Procceses information about where objects are
Ventral stream
The “What” pathway
What does it do
Proccesess information about what objects are
Trichromoatic theory color
Suggests that our ability to perceived color is based on the presence of three types of color receptors (cones)in the retina
These three done types are sensitive to
Specitic wavelengths of light; red, green and blue
Our brain can perceived a wide range of colors by
Climbing the sunglasses from these three types of cones
Color blindness
Defienciens in the ability to distinguish colors
Most color blind individuals are
Dichromate menaing they can only see two of the three primary colors
This kind of color blindness is Rare
Complete color blindness
We have how many types of cones
3 types red, green blue
Who discovered that
George Wald
Out viaula perception is based on
Vision and a combination of other factors
Our visual systems often rely on
Past experiences
Illusory motion
Stationary or no-moving objects creatcthe false impression of motion due to the brains interpretation of visual clues
The Brain automatically fills in missing information from
Surrounding visual clues
This can lead to
Negative space illusions
Negative space illusion
Accused when thr brain struggles to distinguish between the main object and the surrounding empty space
We rely extensively on both __ and __ together with on another
Vision and hearing
Where do sound vibrations enter
The outer ear
They are then
Transmitted to the inner ear and choclea by three small bones called the ossicles
Ossicles
Three small bones in the middle ear that transmit air vibrations from the outer ear to the inner ear to be processed as sound
What are the three bones
Stapes, industry and malleus
What is the smallest bone in the body
Stapes
Visual information reaching the brain must then be
Perceived
Hubel & Wiesel discovered that certain cells in the brain respond to
simple shapes
Give an example
Cells may respond to a particular angle of line, line width, etc.
These neurons, located in VI, are called
feature detectors
Feature Detectors
Neurons that respond selectively to very specific visual features of
more complex stimuli.
Feature detectors respond
to very simple shapes
Those simple shapes are combined
in the brain to aid with pattern recognition
This is called
Feature Analysis
Feature Analysis
The process of detecting specific elements in visual input and
assembling them into more complex forms
The brain also has separate pathways for
processing different types of visual information
about objects
Dorsal Stream
The Where pathway”
processes information about
about
where objects are
Ventral Stream
The “What” pathway
Processes information
about
what objects are
The earliest theory of color is
trichromatic theory
Trichromatic Theory of Color
suggests
that our ability to perceive color is based on the presence of three types of color receptors (cones) in the retina
These three cone types are __ to specific wavelengths of light
sensitive
What colors
red. green, and biue
by combining the signals from these three cone types, our
brain can perceive a wide
range of colors
Auditory information is transmitted to the
brain
Received by the
by the
primary auditory cortex
primary auditory cortex (Al):
The part of the brain, located in the temporal lobe, responsible for processing auditory information, including sound and
speech.
tonotopic map:
A neural arrangement where specific sound frequen cies are
organized spatially for processing in the auditory system
Different regions of Al
and different sound frequencies
Different regions of Al receive and process different sound frequencies
SCCs are also ___ and contain __ ___
fluid-filled, hair cells
This allows
detection of rotational movements of the head
Damage to these systems can cause
vertigo (sensation of motion or spinning, dizziness)
Sound vibrations enter the
outer ear
They are then transmitted to
the inner ear and cochlea by three small bones called the
ossicles
what are the three small bones
- (Malleus, Incus, and Stapes)
Ossicles:
three small bones in the middle ear that transmit air vibrations from the out
ear to the inner ear to be processed as sound
____ is the smallest bone in the human body
Stapes
Many sensory systems are __with one another
integrated / interrelated
Example
We may interpret loud and slow sounding objects as being larger
We rely extensively on both and together with one another
We rely extensively on both vision and hearing together with one another
what we see/hear and what we perceive are two ____ things
what we see/hear and what we perceive are two different things
We also tend to prefer to perceive ambiguous lighting scenarios as
being lit from above
rather than below (the ight-from-above prior”)
the brain alsO automatically fills in
____ information from ___ ___ ___This can lead to
___ ___ ___
the brain alsO automatically fills in
missing information from surrounding visual cues This can lead to
negative space illusions
Negative Space Illusion
occur
when the brain struggles to distinguish between the
main obịect and the surrounding empty space
illusory Motion
stationary or non-moving objects create
the false impression of
motion due to the brain’s interpretation of visual cues
Our understanding of objects comes from
experience
We make assumptions about visual information based on
that experience
Context:
We perceive the sizes of objects relative to their contextual surroundings
What can cause visual illusions
Our perceptual systems making assumptions that are incorrect
Visual Illusions:
An apparently inexplicable discrepancy between the appearance of a visual
stimulus and its physical reality.
Relative Size:
If objects are expected to be the same size, we perceive larger objects as
closer
What we See and what we Perceive are
two different things
Our visual perception is not just based on vision, but also
a combination of other factors as well
Visual illusion illusory motion arises from
the
brain’s attempt to make sense of ambiguous or conflicting visual cues
Our visual systems often rely on __ __
We also make __ about what we are seeing
Assumptions
past experiences
We also make Assumptions__ about what we are seeing
Trichronmatic Theory explains ____ well
color-blindness well
Color-blindness
Deficiencies in the ability to distinguish colors
Most color-blind individuals are
dichromats
dichromats :
can see only two of the three primary colors
Complete color-blindness is
is rare
Trichromatic theory explains __but it dosent not explain some other __
Trichromatic theory explains __but it dosent not explain some other __
Color-blindness, phenomena
After-images
a visual image that persists after a stimulus is removed
Recent work suggests that the reality is that
both theories are partially correct
George Wald discovered that we do have just ____ types of cones: and what are they
3 types
Red, Green, and Blue
- However, later pathways in the visual processing system do seem to code colors as
opposites. give 3 examples
opposites
(blue/yelow, red/green, and black/white)
__ theory, explains this phenomenon
Opponent Process Theory
OPPONENT PROCESS THEORY
Opponent Process Theory
Explains
color perception as a result of opposing pairs of color receptors
3 Examples
- Blue/Yellow
- Red/Green
- Black/White
When one experiences sensory adaptation, the opposing cells
still fire
Pairs of light-sensitive cells respond to
opposing colors
