Sensation and Perception Part 1 Flashcards
Sensation»»» ________»»» perception.
transduction
As humans we have various ____ organs that are tailored to capture environmental _______.
sense, stimulus
What environmental stimulus does the eye capture?
It captures light energy
The _____ part comes from the environment.
sensation
What are responsible for sensation?
sense organ
The sensation from the eye is to capture ______ ______.
light energy
What does transduction do?
Turns an environmental stimuli into a neural impulse
Where does perception occur?
in the cortex
What is perception?
When the stimuli input is given meaning.
In order for the environmental stimuli to be seen what must happen?
it must be put into a form that the brain understands.
Explain the problem of depth.
Information received on the eye is 2D but the world we see is 3D.
Visual Information is ______.
indirect
Describe the image that is created in the image of the eye.
Its upside down and back to front.
Because the image in the eye is upside down and back to front, what does this tell us?
There is some interpretation.
The image we receive is from the _____ ______ off an object, that is _______.
light, reflected, indirect
What do we rely on to see an object?
The light bouncing off the object.
Our perception of the world is not merely a _________ process.
passive
We are not simply receiving information, we are ______ it.
constructing
______ of the stimulus is necessary.
Interpretation
What sense is vision called?
Our primary distance sense
Visions stimulus is _____.
light
What can light vary in?
Intensity (amplitude) and wave length.
Name what is formed from oscillating waves of radiation (determined by amplitude and wavelength).
Electromagnetic Radiation
Roughly we perceive the intensity (amplitude) of light as _______ and wavelength of light as _______.
brightness, colour
The sense organ for vision is the ____.
eye
The eye is well designed to _____ light energy and pass it onto the ______.
capture, brain
What do structures like the iris and lens do (generally speaking)?
they control the amount of light entering the eye and form the retinal image.
Whereabouts in the eye does the light come into?
The light comes into the cornea.
After the light comes into the cornea what happens to the light?
The light is then focused by the lens.
What does the lens focus the light onto?
the retina
What is the fovea?
The fovea is a dip in the retina that has a concentrated number of specialised neurons that respond to light energy.
What is the fovea important for?
Its very important in order for us to see in detail.
What is the dart board and the bull’s-eye?
Think of the retina as a dart board and the fovea as the bull’s-eye.
What is the Optic Nerve?
The optic nerve is the first part of the pathway from the eye to the brain.
Where do the nerves leave the eye?
the optic disc
What cells become the optic nerve?
Gagillion cells.
What are photoreceptors?
Photoreceptors are specialised neurons that capture light
How many types of photoreceptors are there?
2- Cone cells and Rod cells
Where are photoreceptors found in the eye?
In the retina.
Cone cells are found in the ______.
fovea.
What do cone cells give rise to?
They give rise to colour sensation and detail- fine visual acuity.
____ cells are packed at the fovea.
cone
What photoreceptor gives us the ability to see clearly in colour?
Cone cells
Rods are ____ and ______ detectors.
black and white
Rods don’t give any information on ______ or give rise to _____ and ____ _____ ______.
colour, detail, fine visual acuity.
Primarily what are rods used in?
Rods are used in low light conditions.
There are _____ million rods in the retina compared to____ million cones.
120, 6
Where are rods concentrated?
The rods are concentrated in the peripheral.
Name the 3 types of cone cell.
Short, medium and long
Each type of neuron _____ and ______ more to light energy optimally at different ____________.
absorbs, responds, wavelengths
Short cones respond to _____ wavelength light.
short
What colour is short wavelength light?
Blue
_____ cones respond to medium wavelength light.
medium
What colour is medium wavelength light?
green
Long cones respond to _____ wavelength light, the colour of this light is _____.
long, red
There is only 1 type of ____ cell.
rod
How many visual areas are in the brain?
5 :)
The 2 arches (think of rainbow) at the very back of the cortex are known as what?
V1 and V2
What are V1 and V2 responsible for?
First and Second level processing.
What happens at first and second level processing?
form, colour and motion are sorted and separated to then be passed on to regions of the brain for further processing.
What is V3 responsible for?
Shape in motion
V3 has _____ which respond to the _____ of _____ of an object which correspond to the object being in ____ ______ but tilting or ____ somehow.
cells, motion, edges, one place, changing
What is V4 responsible for?
Colour
V4 specialises in ___ with a tiny bit of _____.
colour, motion
V3 is to do with the ____ and _____ of an object.
form, motion
At V4 the cells look at the ______ colour and not at the _____ of light.
perceived, wavelength
What is V5 responsible for?
Global motion
Unlike V3, V5 responds to _______ ________.
overall motion
Name 2 things V5 can respond.
speed and direction
What body part is responsible for knowing the identity of an item?
infero-temporal cortex
Light reflected off of images enters the eye through the _______.
cornea
Where is the light focused onto and with what?
The light is focused onto the retina via the lens
What are the specialised cells in the retina called?
Ganglion cells
What is the role of ganglion cells?
To convert light rays into electrical signals.
Electrical signals are then sent through the neural pathway to the brain. What are these signals carried by?
The optic nerve
The optic nerve carries signals through the lateral ________ nuclei and to the _____ _______ of the brain.
geniculate, visual cortex
It’s in the visual cortex that images are ______.
“seen”
Name 2 things that happen when perception goes wrong.
- We see things that aren’t there
- We fail to perceive things that are perfectly visible
The visual system should come to a _____ of what we should see.
hypothesis
In visual perception , we perceive objects on what?
On what we have already seen before :)
Visual perception is mostly _____ ______.
problem solving
In the brain, if the visual ____ doesn’t support the original ______, it is then ___________.
data, hypothesis, reconsidered
In what circumstance would we initially not be able to perceive what an object is?
Only when the initial stimulus isn’t obvious.
What does subjective contours illustrate?
It illustrates the constructive nature of perception.
When we create a shape that isn’t actually there, what would this be called?
Subjective contours
Explain subjective contours.
A shape is generated by the brain (that isn’t really there) due to the effect of knowledge and experiences.
Define change blindness.
The failure to notice/perceive the obvious change eg. don’t see an object disappearing
What is the failure to notice the existence of an unexpected item known as?
Inattentional blindness
Inattentional blindness is the failure to notice __________.
the existence of an unexpected item
Why does change blindness and Inattentional blindness occur?
As the brain has limited resources so can’t process everything in a scene- this is why things/changes that are obvious can often be overlooked. :)
What do contrast effects give rise to?
Visual illusions
The difference in brightness or colour in a visual scene is known as ______.
contrast
Explain the visual illusions of mach bands.
The same colour is throughout each band but contrast makes the band appear different shades.
What do mach bands illustrate?
That our perception doesn’t correspond to visual properties.
Visual illusions display the ______ nature of _____ ________.
interpretive, visual, perception
Name the visual illusion where we perceive spots between squares that aren’t there, this occurs due to contrast.
Hermann Grid
Visual sensations can vary in ______.
colour
Name the 3 terms used to describe colour sensations.
Hue (colour)
Brightness (how dark/light)
Saturation (vividness of the colour)
Normal human colour vision is _______.
trichromatic
Trichromatic vision depends on what?
The 3 different cone cell types
There are ___ separate pathways for processing colour, what is this known as.
3, Trichromatic theory
What are the 3 colours that are processed?
red, green and blue
What evidence is there against the trichromatic theory?
Not all colours can be perceived together eg. we can’t perceive a reddish green.
Name the 3 antagonistic opponent process pairs.
Red and Green
Blue and Yellow
Black and White
How does the Opponent-Process theory work? - use red and green to explain this :)
If the red was excited then green would be inhibited.
Name 2 visual illusions that provide evidence for the opponent-process theory.
colour contrast and negative afterimages
Blue can induce yellow in a neighbouring area what is this known as?
Colour contrast
What is a negative afterimage?
When red inverts to green (after you stare at it for a while).
Vision is an ___, _____ process.
active, constructive
The visual system actively accentuates important features such as ______.
edges
There are ____ types of photoreceptors- _____ and ______.
2, rods and cones
What processes the information from the eyes?
The visual cortex
Normal human vision is ______, depending on 3 ____ types.
trichromatic, cone
