Midterm 2: Chapter 5 Flashcards
The task of determining the object responsible for a particular image on the retina.
- it involves starting with the retinal image and extending rays out from the eye.
Inverse projection problem
When does the problem of hidden objects occur?
Anytime one object obscures - or “occludes” part of another object
True or False: People are able to recognize objects that are not in sharp focus, like faces.
TRUE
The ability to recognize an object seen from different viewpoints.
Viewpoint Invariance
The process by which elements in a person’s visual field become perceptually grouped and segregated to create a perception.
Perceptual organization
Distinguished between sensations —elementary processes that occur in response to stimulation of the senses—and perceptions, more complex conscious experiences such as our awareness of objects.
Structuralism by Wilhelm Wundt
Although movement is perceived, nothing is actually moving.
Apparent Movement
Did Gestalt psychologists agree with structuralism?
NO; they rejected the idea that perceptions were formed only by “adding up” sensations.
What were Max Wertheimer’s two conclusions from the phenomenon of apparent movement?
- Apparent movement can’t be explained by sensations alone because there is nothing in the dark space between the flashing light.
- The whole is different than the sum of its parts because the perceptual system creates the perception of movement where there actually is none.
There are no physical edges present, yet we perceive them as there.
Illusory Contours
Determine how elements in a scene become grouped together.
Principles of perceptual organization
Points that, when connected, result in straight or smoothly curving lines are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path.
Law of Good Continuity
Objects that are partially covered by other objects are seen as continuing behind the covering object.
Law of Good Continuity
Every stimulus pattern is seen in such a way that the resulting structure is as simple as possible.
Law of Simplicity
Similar things appear to be grouped together; grouping can occur because of similar color, shape, size, or orientation
Law of Similarity
Things that are near each other appear to be grouped together.
Law of Proximity
Things that are moving in the same direction appear to be grouped together.
Law of Common fate
Elements that are within the same region of space appear to be grouped together
Law of common region
A connectedness region of the same visual properties, such as lightness, color, texture, or motion, is perceived as a single unit
Law of Uniform Connectedness
TRUE or FALSE: Proximity overpowers connectedness
FALSE; connectedness overpowers proximity
When we see a separate object, it is usually seen as a figure that stands out from its background, which is called the ground.
FIgure-ground segregation
Can be perceived alternately either as two dark blue faces looking at each other in front of a grey background or as a gray vase on a dark blue background.
Reversible figure-ground
Property of the border belonging to one area.
Border ownership
Determines which areas are perceived as figures.
- determine how an image is segregated into figure and ground
Figural cues
What are some examples of figural cues?
- Areas lower in the field of view are more likely to be perceived as figures (the figure is much more likely to be below the horizon because that’s how we perceive it everyday)
- Figures are more likely to be perceived on the convex side of borders.
Objects are comprised of individual geometric components called geons, and we recognize objects based on the arrangement of those geons. Geons are 3D shapes, like pyramids, cubes, and cylinders.
Recognition by components (RBC) theory
What is a limitation of the RBC theory?
It doesn’t account for grouping or organization, and some objects simply can’t be represented by assemblies of geons.
It also doesn’t allow for distinguishing between objects within a given category.
A view of a real-world environment that contains
1. background elements
2. multiple objects that are organized in a meaningful way relative to each other and the background.
Scene
General description of the type of scene
Gist of a scene
The perception of a visual stimulus continues for about 250 ms (1/4 second) after the stimulus is extinguished.
Persistence of vision
Usually, a random pattern covers the original stimulus, so if a picture is flashed for 100 ms followed immediately by a masking stimulus, the picture is visible for just 100 ms.
Visual masking stimulus
Describe Fei-Fei’s experiment at each level when describing a scene of a boy and his father looking at a computer
27 ms - looked like something black in the center with 4 straight lines coming out of it against a white background.
40 ms - could recognize a dark splotch in the middle
67 ms - Sees a person sitting down or crouching. Facing the left side of the picture. We see their profile mostly. They were at a table or where some object was infront of them.
500 ms - This looks like a father or somebody helping a little boy. Man has something in his hands, like a computer.
They can be received rapidly and are associated with specific types of scenes.
Global image features
Natural scenes, such as the ocean and forest, have textured zones and undu- lating contours. Man-made scenes, such as the street, are dominated by straight lines and horizontals and verticals.
Degree of naturalness
Open scenes, such as the ocean, often have a visible horizon line and contain few objects. The street scene is also open, although not as much as the ocean scene. The forest is an example of a scene with a low degree of openness.
Degree of openness
Smooth scenes (low roughness) like the ocean contain fewer small elements. Scenes with high roughness like the forest contain many small elements and are more complex.
Degree of roughness
The convergence of parallel lines, like what you see when you look down railroad tracks that appear to vanish in the distance, or in the street scene, indicates a high degree of expansion. This feature is especially dependent on the observer’s view- point. For example, in the street scene, looking directly at the side of a building would result in low expansion.
Degree of expansion
Some scenes have characteristic colors, like the ocean scene (blue) and the forest (green and brown).
Color
What are the properties of global image features?
- They are holistic ad rapid perceived
- They contain info about a scene’s structure and spatial layout
- Our past experiences in perceiving properties of the environment play a role in determining our perceptions.
Regularly occurring physical properties of the environment.
Physical regularities.
We usually assume that light is coming from above because light in the environment, including the sun and most artificial light, usually comes from above.
Light-from-above assumption
Refers to the meaning of a scene
Semantics
Characteristics associated with activities that are common in different types of scenes.
Semantic regularities
Knowledge of what a given scene typically contains
Scene Schema
- realization that the image on the retina is ambiguous
- a theory where our perceptions are the result of unconscious assumptions or inferences that we make about the environment
Theory of Unconscious Interference
We perceive the object that is most likely to have caused the pattern of stimuli we have received.
Likelihood principle
The idea that our past experiences help us make informed guesses about what we will perceive
Prediction
our estimate of the probability of an outcome is determined by two factors:
1. the prior probability, or simply the prior, which is our initial estimate of the probability of an estimate.
2. The extent to which the available evidence is consistent with the outcome (the likelihood of the outcome)
Bayesian Inference
A theory that describes how the brain uses our past experiences to predict what we will perceive.
Predictive Coding
A region of the brain that plays a key role in object recognition and shape perception; is activated by objects regardless of their size, orientation, position, or other basic features.
Lateral Occipital Complex (LOC)
- a region in the brain that is specialized for recognizing faces:
- Located in the lateral middle fusiform gyrus of the inferior temporal cortex
- Processes faces holistically, recognizing facial features and their arrangement
Fusiform Face Area (FFA)
What do you get when there is damage to the FFA?
Prosopagnosia
Difficulty recognizing the faces of familiar people.
Prosopagnosia
Initial processing
Occipital Cortex
Basic face processing
FFA
- Emotional reactions (face expressions)
- Familiarity (familiar faces cause more activation)
Amygdala
Evaluation of attractiveness
Frontal Lobe
- Gaze direction
- mouth movements
- general face movements
Superior Temporal Sulcus (STS)
- activiated by pictures depicting indoor and outdoor scenes.
- a brain region that processes visual information about places and scenes, such as buildings, natural landscapes, and cityscapes
- a “PLACE” area
Parahippocampal Place Area (PPA)
What is important for the PPA?
info about spatial layout because increased activation occurs both in empty rooms and in rooms that are completely furnished.
Identifies the location of the area in the brain without making a statement about its function.
Parahippocampal cortex
Proposes that the PPA/PHC responds to the surface geometry or geometric layout of a scene
Spatial layout Hypothesis
How does fMRI measure activity?
in voxels
What does the pattern of voxels activated depend on?
the task and the nature of the stimulus being perceived
A computer program that can predict the most likely stimulus based on the voxel activation patterns observed in the calibration phase.
Decoder
What do faces establish?
- a person’s identity, important for social interactions
- provides info about a person’s mood and where the person is looking, and can elicit evaluative judgements
What has the inversion effect been interpreted as providing?
Evidence that faces are processed holistically; our ability to distinguish thousands of different faces seems to be based on our ability to detect the configuration of these features.
The idea that our proficiency in perceiving faces and the large face response in the FFA can be explained by the fact that we have become “experts” in perceiving faces because we’ve been exposed to them for our entire lives.
Expertise hypothesis
What support is there for the expertise hypothesis?
Isabel Gauthier used fMRI to determine the FFA response to faces and to objects called “Greebles” - families of computer-generated “beings” that all have the same basic configuration but differ in the shapes of their parts
At birth, what is vision like?
the contrast perceived between light and dark areas is so low that it is difficult to determine a face.
By 8 weeks after birth, what is vision like?
the infant’s ability to perceive the contrast between light and dark perception has improved so that the image looks clearly facelike.
By 3-4 months after birth, what is vision like?
Infants can tell the difference between faces that look happy and those that show surprise, anger, and are neutral
What did Ian Bushnell (infant researchers) find and conclude?
newborns looked at the mother’s face about 63 percent of the time. He concluded that 2-day-olds could recognize their mother’s face
What info do the infants use to recognize the mother’s face?
The hairline, the high-contrast border between the mother’s dark hairline and light forehead, apparently provides important info about the mother’s physical characteristics that infants use to recognize the mother.
Occurs when the neural activity in two different areas of the brain is correlated
Functional connectivity
