Perception Exam 1 Flashcards
The periphery of the eye is excellent at detecting a small flash of light in the dark, but less able to distinguish changes in the strength of an existing light. If we think about this in terms of thresholds, what can we conclude?
Psychophysics
_______ is the principle that describes the relationship between a stimulus and its resulting sensation, which says the magnitude of subjective sensation is proportional to the stimulus magnitude, raised to an exponent, which may differ between varying senses.
Steven’s Power law
Which of the following statements about the action potential is FALSE? [know the basics about action potentials]
True about action potentials: neurotransmitters trigger an electrical shift in the post-synaptic neuron, leading to the neuron “firing” an action potential
-how to tell how excited the neuron is during action potential: # of spikes per second
-they start near cell body of neuron, goes down axon, and ends at axon terminal
Absolute threshold is the minimum amount of stimulation necessary for a person to detect a stimulus _______% of the time.
50%
Which is NOT a key difference between Fechner’s and Stevens’s Laws?
- Logarithmic (fechner) vs Power (stevens) scale
- Both make broad assumptions about the “fit” of data to their metrics and about the scales they work on
- Both are only approximations of data and tuen out to not really be “laws”
- Main takeaways:
o Peoples internal perception can be modeled/predicted
o Sensation is proportional to other parameters
As an aside, there are few, if any, true LAWS in psychology
The method of _______ requires the random presentation of many stimuli, one at a time, ranging from rarely to almost always perceivable
Constant Stimuli
What differentiates the method of Limits from the method of Adjustments?
Method of Limits: researcher controls the magnitude
Method of Adjustments: participant controls it
When setting up a new monitor or video game, there is often a step in which you change the brightness of the screen until a logo is just barely visible. This is an example of
Method of adjustment
_______ is a psychophysical method in which the participant assigns values according to perceived magnitudes of the stimuli.
Magnitude Estimation
According to Signal Detection Theory, which of the following would result in an INCREASE in Hits?
Increasing the stimulus strength (decrease in miss)
If a stimulus is absent and the observer reports it as absent, this is called a
correct rejection
The criminal justice system in United States is designed to be biased such that it would rather let a guilty person go free than convict an innocent person. In terms of signal detection theory, the courts would rather have a _______ than a _______.
Miss, False alarm
Airport security is very tight. If a traveler even jokes about a bomb, they are detained and questioned to ensure that no real terrorist threat succeeds. In terms of signal detection theory, airport security is prioritizing _______, even if it results in this kind of error: _________.
False alarm, miss
how many cranial nerves are there?
12
The thalamus is deep in the brain, and not on the brain’s surface. Which technique would be a bad choice to look at the structure of the thalamus?
MEG
_______ makes it possible to measure localized patterns of activity in the brain by tracking changing levels of blood oxygenation
Functional Magnetic Resonance Imaging (fMRI)
A cranial nerve that sends information TO the brain from the body, is called _________ and is generally considered ________. [note: I am not asking about Cranial nerve #’s but types of cranial nerves]
Afferent, sensory
Byron is testing salty and sweet taste perception. He gives participants different cups of liquid and asks them to rate how salty and how sweet each liquid is. What two methods does this combine?
Scaling methods and magnetic estimation
When thinking about the physics of light, which of the following are true statements? [I will give you statements about the basic physics of light and you’ll need to identify which is not correct]
Absorbed: light is taken up and is not transmitted further
Scattered: light is dispersed in an irregular fashion
Reflected: light is redirected, generally back the way it came
Transmitted: light is passed through a surface (without being reflected or absorbed)
Refracted: light is altered as it passes through a medium/object but is being bent or modified
When you look at an opaque, solid red surface, what is happening to the light that hits it?
some is reflected and some is absorbed
Based on the physics of light, what is one contributing factor to why the sky appears red when the sun is low (sunset) vs. when the sun is high (noon)?
Sunset: reddish orange at dawn/dusk as the syn is not direct and therefore scatters more
Noon: blue light during the day as the sun is direct and not a lot of blue light is scattered
The transparent “window” on the outer part of the eye that allows light into the eyeball is called the _________________.
the cornea
what portion of the eye makes up 80% of its size?
Vitreous Chamber/Humor
Which part of the eye undergoes accommodation?
the lens
When considering the fovea, macula, and periphery, what is the pattern of sensitivity to light in low-light situations (from most sensitive to least sensitive)?
periphery, macula, fovea
which cells actually sense light?
rods and cones
People with _______ do not require an optical correction to see normally.
Emmetropia
Which is Not a mechanism for dark/light adaptation?
the 4 mechanisms:
1. pupil dilation
2. photopigment replenishment
3. duplex retina
4. neural circuitry beyond rods/cones
Suppose your pupils are dilated after visiting the eye doctor. What is the likely effect on the amount of photopigment in your photoreceptors, and why?
You have less photopigment than normal because your photoreceptors are trying to adapt to the increased amount of light striking the retina
In aging-related macular degeneration (AMD) there is a _______ loss of _______ vision.
severe, central
The part of the photoreceptor that stores photopigment molecules is called the
outer segment
when light strikes a photoreceptor, what happens to its electrochemical process?
it triggers an electrical signal (reduces amount of glutamate)
what is lateral inhibition
process of adjacent cells at the same level blacking, or inhibiting, each others effects
why is lateral inhibition important for retinal ganglion cell receptive fields?
it creates the center-surround receptive field structure, which acts a filter for perception
Which of the following are retinal cells that synapse with photoreceptors, horizontal cells, and ganglion cells?
Bipolar cells
. In the fovea, single cones pass information to single ganglion cells via _______cells.
Midget
The vertical pathway in the retina consists of all the following except
amacrine cells
P ganglion cells are different than M ganglion cells in that P ganglion cells…
P ganglion cells can transmit information about color, whereas M cells cannot
or
P= small, high acuity, more cells
M= large, low acuity, few cells
Which stimulus would optimally activate an OFF-center ganglion cell?
a shadow in the center of the receptive field
An ON bipolar cell in the fovea becomes more depolarized. What else can you conclude has happened to its photoreceptor?
increase of glutamate
What is at least one reason we perceive an image as solid gray when the spatial frequencies between black and white bars becomes too high?
Black and white bars are stimulating the same photoreceptors
Visual angle is a measure of the…
the size of the object’s image on the retina
The Snellen Eye Test can be considered a test of what threshold of acuity?
Minimum recognizable
What does the yellow region in the spatial frequency x contrast sensitivity graph refer to?
the low spatial frequencies are fat gratings and high spatial frequencies are thin gratings
or
the visibility of any object whose spatial frequencies and contrasts fall within it
the distance required for one full cycle of a repeating waveform is its
wavelength
the retinal ganglion cell depicted is most responsive to which spatial frequency?
Medium frequency
The parvocellular layer of LGN is _______ and _______ compared to the magnocellular layer:
3,6
The right visual field projects to the _______ half of each eye and then is processed by the LGN in the _______ hemisphere
left, left
An image from the left side of your visual field that falls on your fovea will be represented where in V1?
on the right
What best describes what is represented within every 0.5mm square of V1 columns?
blobs
A _______ cell is a V1 neuron whose receptive field does not have clearly defined excitatory and inhibitory regions
Complex
What phenomenon does the figure BEST demonstrate?
Ganglion On-center receptive fields
Which aspect of a visual stimulus do neurons in CO blobs process?
color and brightness
The diminishing response of a sense organ to a sustained stimulus is referred to as
adaptation
What is the FIRST part of the visual system where a single cell can process information from both eyes?
the primary visual cortex
With regards to column size, ocular dominance columns are generally _______ relative to orientation selective columns.
adjacent
Selective adaption studies of orientations and frequencies demonstrated which of the following:
Orientation: tilit aftereffect
Spatial frequency: threshold elevation in contrast sensitivity
If you record from cells in a particular orientation selective column, what can you say for sure if you were to record from an adjacent orientation selective column in any direction?
If you drop 1 column, all you really know is the next one over will be slightly different orientation
How would V1 vs V2 cells with the red oval receptive field respond to these images?
codes which part of a visual image is object and which is background
what is one caveat for why grandmother cells are still consider hypothetical:
a particular cell will like
one facial stimulus more than the others-cannot sample faces so the cells may like it more
what is the main effect seen in agnosia?
can affect you senses including vision, hearing, smell, taste, and touch
A _______ process is one that carries out a computation (e.g., object recognition) one neural step after another, without the need for feedback from a later stage to an earlier stage.
feed-forward process
Which theory suggests that you initially get a general, categorical impression of the world from higher brain areas and then later appreciate details after activation flows back down to lower brain areas?
reverse-hierarchy theory
The processing that happens between V2 and V4 is generally considered what kind of vision?
“what” pathway
which of the following is not one of the principles for summarizing mid-level vision?
seek ambiguity and avoid consensus
A photo that appears to show a person “holding” the sun from a given angle shows what concept?
forced perspective
If an animal has a pattern on its body that provides camouflage and allows it to blend seamlessly into the background, it is trying to prevent _______ by predators that would reveal its location.
texture segmentation
The principle of relatability helps us to understand
when edges do or do not appear to connect behind occluders
What brain region has cells that respond to shapes that are more complex than bars or edges, but not quite objects?
primary visual cortex
Which of the following DOES NOT support the assertion that faces are a special kind of object recognition?
prosopagnosia
What is one piece of evidence that supports the concept of template models over geon-based models?
it is more efficient
What are object representations made of, according to the recognition-by-components model of object recognition?
Geons
a potential criticism of template theories of object recognition is that idea that
we’d have to have tons of templates, seems relatively slow to sift through lots of templates
A dog expert and a dog novice are in the park when a border collie dog passes by. What label will each of these people likely use to describe this pet?
template model
What is one reason basic/entrant level categories tend to be the most commonly used when labeling an object?
Structural models/geons
