Chapter 3: Perception and Mental Imagery Flashcards
Perception
the ability to recognize and interpret information from the senses
(T or F) The very act of perceiving involves making sense of the raw stimulation conveyed by our senses
True
Blind Spot
Each of our eyes have it; its toward the outside edges of our vision, where the optic nerve passes through to convey visual signals to the brain. We don’t notice this gap in our visual experience of the world because our minds fill-in the missing information
Model Completion
Your view of an illusory object is not obstructed, and where there is no objective boundary between the illusory object and the background
Amodal Completion
Where you seem to perceive an object despite an apparently obstructed view
(T or F) Perception is a cognitive act
True
(T or F) What you consciously perceive is NOT heavily shaped by what your mind chooses to see, hear, taste, feel, or smell
False
What was George Berkley’s contribution?
“To be is to be perceived”, meaning that an object doesn’t exist if your mind doesn’t perceive it.
Bottom-up processing
The sensory input, such as an image, coming through the eyes and falling on the retina, or sounds impinging on the ears, stimulating the cochlea
Retina
the light-sensitive part of our eyes
In vision, light reflected by objects in the world passes through our eyes and stimulates a collection of more than 100 million _____ on the retina at the back of each eye
Photoreceptors
The center of the retina, known as the _____, contains densely packed photoreceptors known as _____, which are differentially sensitive to wavelengths corresponding to different colors.
- Fovea
- Cones
(T or F) The retina also contains extremely light-sensitive photoreceptors known as rods, which come in handy when light is very dim but which do not distinguish among colors
True
Sensation
The input for perception - the stimulation of the sensory receptors
Transduction
The process by which physical signals from the environment are translated into neural signals that the brain can use
Through transduction, signals are projected all the way to the _____, which is located at the ______
Primary visual cortex
Back of the brain
(T or F) The primary visual cortex is specialized for the most rudimentary visual processing, such as determining the orientations and spatial frequencies of light and dark patches in the visual world.
True
Feedforward System
the hierarchical account of the flow of visual information processing
Top-down information
the knowledge and expectations that influence and enhance our interpretation of sensory input
What 2 things shape perception, and what makes predictions in perception?
- CONTEXT SHAPES PERCEPTION
- EXPERIENCE SHAPES PERCEPTION
- VISUAL BRAIN MAKES PREDICTIONS
Predictive coding
The visual brain seems to operate by making predictions about what input the eyes are about to receive
Cognitively Impenetrable
those who argue that perceptual processing proceeds without influence from “high-level” cognition - for example, beliefs, knowledge, or motivation that suggest this
Object Segmentation
Visually assigning the elements of a scene to separate objects and backgrounds
Figure-ground organization
When the boundary between an object and its background is clear, and it’s not always evident which side of the boundary belongs to the object (or figure) and which side of the boundary belongs to the background
How do people decide which side of a shared boundary is the figure and which is the ground?
According to current models of figure-ground organization, the sides falling on either side of a shared boundary activate representations that compete with each other for “figure status”, with the winning representations inhibiting neural activity corresponding to the losing representation
What are the rules researchers discovered that resolve the competition in figure-ground organization?
- Rule of enclosure
- Rule of symmetry
- Rule of convexity
- Rule of meaningfulness
Occlusion
Refers to the fact that our views of objects are often partially blocked by other objects. The brain needs to “fill in”, or infer, the missing information, a process known as a modal completion
Boundary Extension
Where people tend to remember pictures as having extended beyond their edges, as if their minds fill in a little bit of what the scene would have looked like had it not been cut off at its border
Inverse Projection Problem
Refers to the fact that we live in a three-dimensional (3D) world, but the input to our eyes is two-dimensional (2D)
We cannot tell from a given ____ retinal image what the _____ object is out there in the physical world
- 2D
- 3D
Binocular disparity
The closer something is to you, the greater the difference between what your two eyes see
Binocular depth cues
Cues that require both eyes to be effective
Monocular depth cues
The cues your mind uses to construct a 3D understanding of the 2D image cast on your retinae
Linear perspective
Refers to the way parallel lines appear to move closer together and converge on a single point (a vanishing point) as they recede into the distance (monocular clue)
Texture gradient
Refers to the way textural elements that are presumably of similar size appear to get smaller and more densely packed together as they recede into the distance (monocular clue)
Object constancy
Refers to the fact that although the same object looks very different on the retina depending on its orientation
Size constancy
Refers to the fact that the perceived sizes of objects are remarkably stable despite radical differences in their image size on the retina
Color constancy
When our visual system factors in differences in illumination when shaping our color perception
Lightness constancy
When our minds factor in illumination conditions when perceiving the brightness of things
Object recognition would remain difficult because of what 3 variations?
- Variation in shape
- Variation in orientation
- Variation in lighting conditions
Agnosia
The inability to recognize objects
Apperceptive agnosia
Individuals who seem to have impaired early vision, because they cannot perform even the simplest visual feature tasks; they are unable even to copy images
Associative agnosia
Early vision (perception) seems intact, as individuals can copy what they see; it’s the inability to name objects attributed to a later stage of recognition and categorization
View-based approach
Claims that we match images to representations that are like two-dimensional pictures or templates.
What is a template in the view-based approach?
It is a representation that fully describes the shape of an object
Structural descriptions
Models that represent objects as sets of three-dimensional parts standing in spatial relationships to each other
Biederman’s recognition by components
Biederman proposed that there is an alphabet of about 36 or fewer basic shapes, or goons, and different combinations of goons allow for representation of different objects, and it has been estimated that combinations of up to three goons can yield about 154 million distinct structure.
The view-based approach proposes that we store multiple representations corresponding to multiple views (or templates) of the same object, allowing us to quickly match an incoming object to the corresponding representation. This is also known as the _________.
Multiple-trace memory model
Holistic Perception
We process a whole object at once, including the relations of the individual parts to each other
Disorders that involve difficulty processing faces — such as autism and schizophrenia — have been linked to diminished ________
Holistic processing
Deep learning
A form of artificial intelligence that uses deep neural nets — brain like algorithms that analyze images in multiple steps — to process, categorize, and label natural images
What is the process of deep learning?
1st stage process the raw image, while subsequent layers extract more abstract features that make recognition more robust across image changes and noise. The final layer, or output, can be a categorization label, allowing the algorithm to name a cat image as a cat
Ventral cortex
Is more active when asked to focus on objects
Dorsal cortex
More active when performing a location task on similar types of stimuli
Perception pathway
Allows us to determine what is located where
Action pathway
Uses perceptual information to guide ongoing actions
Mental imagery
The act of forming a percept in mind without sensory input
Aphantasia
the inability to engage in mental imagery
Mental rotation
Mental imagery is important for this; it compares and rotates images. In the time it takes to mentally rotate and match two objects is directly proportional to the amount of rotation that separates the objects
What are the two explantations for mental imagery?
- Kosslyn’s depictive view
- Pylyshyn’s propositional view
Depictive mental imagery
Suggests the brain represents mental images like it represents real images coming through the eyes
Propositional Mental Imagery
Suggests that mental images are held in post-perceptual, abstract way, more like a linguistic description than a picture.
Mental scanning
The process of mentally moving from one point in an image to another
Epiphenomenon
(Pylyshyn) something that occurs together with a process of interest but is not central for its function
Topographic
Items adjacent in visual space are represented by neurons that are close to each other in the cortex; the occipital cortex is like a map that reveals activity in the visual world
Spatial neglect
People who cannot visually attend to objects on one side of their visual field
