Chapter 5: Object Perception Flashcards
Bottom-up processing:
a process whereby physical stimuli influence how we perceive them
Top-down processing:
a process whereby our existing knowledge of objects influences how we perceive them
Recognition:
the ability to match a presented item with an item in memory
Representation:
the storage and/or reconstruction of information in memory when that information is not in use
it is the neural code for what the object is
how networks of neurons across the brain store the information we will need to retrieve at some point
Perceptual organization:
the process by which multiple objects in the environment are grouped, allowing us to identify multiple objects in complex scenes
this allows us to group what we see into coherent perceptions
Examples of low-order
detecting edges
neurons activating only when detecting shapes
Example of high-order
imagination, driving
distinguishing objects, acting on senses and creating an understanding of it
Grouping:
the process by which elements in a figure are brought together into a common unit or object all visual pieces perceived as one unit
Segregation:
the process of distinguishing two objects as being distinct or discrete
Figure–ground organization:
the experience viewers have as to which part of an image is in front and which part of an image is in the background of a particular scene
Law of good continuation:
the gestalt grouping law stating that edges that are smooth are more likely to be seen as continuous than edges that have abrupt or sharp angles
Law of proximity:
the gestalt grouping law stating that elements that are close together tend to be perceived as a unified group
geons
basic units of objects
they consist of simples shapes
Law of similarity:
the gestalt grouping law stating that elements that are similar (e.g., color, orientation, size, motion) to one another tend to be perceived as a unified group
Law of symmetry:
the gestalt grouping law that states that elements that are symmetrical to each other tend to be perceived as a unified group
Law of common fate:
the gestalt grouping law that states that elements that are moving together tend to be perceived as a unified group
Edge completion:
the perception of a physically absent but inferred edge, allowing us to complete the perception of a partially hidden object
Referring to the ventral pathway, information leaves V1 and goes to …
V4
What is V4 linked to?
color vision, shape vision, and edges (specifically CURVED edges)
Referring to the ventral pathway, information leaves the occipital cortex and goes to the …
inferotemporal (IT) area of the temporal lobe
What distinguish the neurons in the IT with those in V1 and V4?
Neurons in the IT have a larger receptive field, detecting specific objects rather than specific features (V1 neurons only detect darkness, or shapes)
Neurons in _________________ make initial identification of face to shape/arrangement.
Extrastriate cortex
it is active for face-like shapes in general
Neurons in _____________ identify WHO the face is.
Fusiform Face Area
it has a strong connection to familiar faces
What are three other IT areas?
Parahippocampal Place Area (PPA) (PINK)
Extrastriate Body Area (EBA) (PURPLE)
Lateral Occipital Complex (LOC) : (GREEN) things area
Refer to diagram in slides
Grandmother cells are…
Cells that code for or respond to specific stimuli
To identify an object, your brain must
overcome:
image clutter
object variety
variable views
What three computational difficulties does the visual system have to overcome in order to recognize an object?
1) image clutter
2) object variety
3) variable views
To overcome image clutter means to…
recognize an object despite the overlapping presence of nearby objects
To overcome object variety means to…
recognize a particular object as a member of a particular category
To overcome variable views means to…
recognize an object despite it being placed differently
What are the pros and cons of top-down processsing?
Pros:
- saves processing power
- less pressure
- saves time
Cons:
- mistakes can occur
- biases
- stereotypes
___________ and ______________ are integral to understanding object perception.
memory; representation
What two classes of objects do we recognize?
specific objects as members of larger classes (e.g., the object on the floor as a shoe)
objects as specific instances of that category (e.g., THAT SHOE on the floor is one of my favorite leather shoes)
Being able to recognize specific instances of a particular category is vital in __________________. (two words)
face recognition
Two important processes in perceptual organization are _______________ and _____________.
grouping, segregation
Gestalt theorists claimed that the brain is __________, with __________________. (3 words)
holistic, self-organizing tendencies
higher levels of organization take precedence over lower levels
Gestalt psychology focuses on ____________ processing and ____________ (2 words ) theory
bottom-up; direct perception
For vision, gestalt psychologists argued that what we see is _____________ than _____________ (two words); the process of perception is designed to see the _______ rather than each _____________. (two words)
greater
individual parts
scene
individual piece
According to direct perception theory, sensation is interpreted ___________ rather than through _______________.
directly, inference
this is possible when the stimuli is rich enough to allow the perceptual system to extract meaning directly
What are the two components that we more or less divide the world into?
the figure: the object of concern
the ground: the rest
The ___________ tends to be in the front and bottom of the field of vision.
figure
The __________ tends to be in the back and top.
ground
What are the 5 Gestalt laws of perceptual grouping?
1) The law of good continuation
2) The law of proximity
3) The law of similarity
4) The law of symmetry
5) The law of common fate
_______________ affects figure-ground organization.
symmetry
Images that are symmetricla are more likely to been seen as __________ and therefore in the foreground, whereas less symmetrical images are more likely to be perceived as ____________.
figure; background
What are illusory contours?
perceptual edges that exist because of edge completion but do not actually exist
they are relatively low-level feature of object identification, supporting the gestalt view that we pick up features in the stimulus rather than as a function of nonconscious processing
What are examples of edge completion?
Kanizsa triangle and Necker cube
they have illusory contours, which are perceptual edges that exist because of edge completion but do not actually exist
Neuroscience data with monkeys suggest that edge detection cells in V1 and V2 respond to illusory edges as strongly as they do to real ones. True or false?
True
Who developed one of the most influential bottom-up theories of object recognition?
Irving Biederman
Referring to recognition by components, object recognition occurs by representing each object as a combination of _______ that make up that object.
geons
What are the pros and cons of the bottom-up theory of object recognition by Irving Biederman?
pro: works well with what we know about how neurons respond to basic visual information in V1 and V2
con: does not explain letter and face recognition
Researchers believe dolls’ lack of animate eyes may explain why people view them as “creepy.” True or false?
True
What improves airport security screenings, as supported by research into object perception?
Focusing on one specific object improves each screener’s performance.
Amos is affected by object agnosia. describe his condition.
He can describe objects, but he does not know what they are.
How can object perception research lead to safer airports?
Understanding how the mind perceives objects can help airports create better screening practices.
Eduardo greets those around him by name, but when he is handed a coin, he describes it as “a flat, engraved disc made from metal.” Eduardo most likely suffers from ______.
object agnosia
How does the kitten experiment and the village experiment connect?
the brain can’t tune up to certain stimuli unless exposed to it
Define object agnosia
It is the inability to identify and recognize objects although vision has remained intact.
How is object agnosia different than blindsight?
Object agnosia is different than blindsight as object agnosia has vision intact, while individuals with blindsight are subjectively blind, however they can respond to visual stimuli.
Object agnosia is mainly focused on objects while blindsight is mainly unconscious sight.
What computational difficulties does the visual system face in recognizing objects?
The computational difficulties that the visual system has to face and overcome to recognize objects is image clutter, object variety and variable views.
Overcoming image clutter is being able to recognize an object even though other objects may be blocking it partially.
Overcoming object variety is being able to recognize a particular object as a part of a particular category.
Overcoming variable views is recognizing an object even though it is placed differently (different orientation, upside down, to the side, etc.)
Give an example of bottom-up processing.
Bottom-up processing is when physical stimuli influences the way we perceive them.
An example of this is an individual seeing an object that is unfamiliar and has to look at the part of the object in order to make sense of what the use of the object is or what it may be called.
Give an example of top-down processing.
one example of top down processing could be how modern abbreviations are used, like if I see someone text me wyd, i know from prior knowledge that means “what you doing” and I read it as “what. you doing” not wyd.
What processes are necessary in order to be able to remember an object that you saw earlier?
encoding, storage, consolidation, retrieval (double check)
Describe the gestalt laws of perceptual grouping.
The gestalt laws of perceptual grouping explains how our visual system perceives objects to be whole despite the figures that it has.
1) The law of continuation states that objects that have smooth edges are usually perceived to be as continuous than objects that have abrupt or sharp angles.
2) The law of proximity states that elements or figures that are close to one another are usually perceived to be a unified group.
3) The law of similarity states that when figures or elements that are the same color, or the same orientation, or have the same texture are perceived to be a unified group.
4) The law of symmetry states that when elements are symmetrical to one another they are perceived to be a unified group.
5) The law of common fate states that elements or figures that are moving in the same direction and together are to be perceived as a unified group.
What is recognition by components theory and in terms of object perception.
What does the inferotemporal area of the brain do?
It is in charge of object perception as it has larger receptive fields to do so, rather than only detecting specific features in specific places as is done in the V1 and the V4.
Describe prosopagnosia
Prosopagnosia is a neurological condition where individuals are not able to recognize specific faces. It does not mean that they don’t recognize faces as faces.
Some causes are due to the damage of the FFA, due to strokes, and some people may be born with it.
Some ways that individuals may identify familiar faces is by their voices, their hairstyles, their body structures, etc.
What is the function of the parahippocampal place area?
It’s function is to recognize scenes or spatial landscapes, whether it is indoor or outdoor.
This area is located within the inferotemporal cortex.
What is topographic agnosia?
It is the result of damage to the parahippocampal place (PPA) where individuals are not able to recognize scenes or spatial landscapes.
What is the inferotemporal area? What does it do and what happens when it is damaged?
The inferotemporal area is located in the temporal lobe and it receives information from the ventral visual pathway. It’s function is to identify objects and if it were to be damaged it can lead to an individual getting a neurological condition called object agnosia.
Who developed one of the most influential bottom-up theories of object recognition in the 1980s? And how did he explain that we recognize objects?
Irving Biederman
he explained that we recognize objects by its geons
ex: Airplane can be recognized by 9 geons, but 78% of the time, 3 geons are enough
What approach did getalt psychologists emphasize?
the top-down approach
According to recognition by components, our visual system breaks down objects in the environment into gemoetric ions or _______.
geons
Recognition by components leads us to recognize objects by representing each object as a combination of ______ that make up that object.
Geons
What are the cons of the recognition by components theory?
Is that it does not explain letter and face recognition
What are the pros of recognition by components theory?
It works well with what we know about how neurons respond to basic visual information in V1 and V2
How did some researchers, Quiroga et al. 2005, found evidence of grandmothers cells?
They did single cell recording on the medial temporal lobe.
