Perception Pt.2 Flashcards
Sensation
Registering stimuli energy and transmitting it to the brain
Perception
Adding meaning to the brain signal
The Sense of Touch
-Mechanorecepters -> spine -> somatosensory cortex
-Cortical homunculus
-Activate certain spots
Olfaction
-Chemicals in the air pass through olfactory epithelium to the olfactory bulb in the brain
-There are direct connections to memory and emotion brain regions (0 relay)
-Powerful retrieval cue
Olfactory Epithelium
Strip of tissue containing many receptors
Olfactory Bulb
Tissue in frontal cortex linked with olfaction
Taste System
-Taste buds on tongue, palate, pharynx, upper esophagus (Measures ingested chemicals)
-Sends a message to thalamus and then the primary gustatory cortex
-Vision influences taste
Gestalt Organizational Principles
- Bistable Figures
-Gestalt Psychology
-Visual Grouping Principles that affect how groups are percieved
-The principles of experience, focus on the familiar
Bistable Figures
-We experience spontaneous subjective change in perception
-What factors (constraints) lead us to see on figure vs the other?
Gestalt Psychology
-Top-down organizational principles to deal with ambiguous figures like bistable figures
-Assumptions shared among people
-Context + knowledge
Principle of Proximity
-Objects or features that are close to one another in a scene will be judged as belonging together
-E.g. Grouping lines together / Adidas logo
Principle of Closed Forms
-We see a shape in terms of closed forms, and we like to see items that enclosed as whole
-Close up gaps in our mind -> see as closed
-E.g. Panda / 3 packman shapes + white triangle
Principle of Good Contour
-We perceive objets as continuous in cases where it is expected that they continue
-E.g. see a continuous line and not as individual dots
Principle of Similarity
-We organize objects or features of a scene based on similarity
-E.g. X’s and O’s perceived as grouped together (just next to eachother)
Principle of Experience
-Image segmentation (figure-ground) depends on sensory input, detect edges or shadows (bottom-up processing)
- Experience + knowledge also drives figure-ground segmentation
-Easier to segment a pen from a background if your very familiar with pens
-E.g. If you’re not familiar with a saxophone, here you will see a woman’s face with a blue background
-E.g. You see a duck or rabbit depending on the time of year
Direct Models
-Requires an ecological approach to understand perception - study it in the real world
-The ambient optical array (AOA) that reaches the retina has enough information to direct perception and movement
-There are cues in the AOA (not in the mind) that are used to guide perception + action
Cues in the AOA : Topographical Breakages
-Discontinuity helps see edges and define objects
-Where they stop and start
Cues in AOA : Scatter Reflection
-How widely light scatters off an object’s surface provides cues about the nature of the surface
- Light is less scattered (E.g. smooth surface, counter)
-Light will scatter widely (E.g. rough surface, sandpaper)
Cues in AOA : Texture Gradients
-Near objects are farther apart and far objects are closer together
-Incremental changes in texture can provide information about your movement and distance
Affordances
-Cues indicate potential function of an object
-We ‘see’ based on what we can/need to do in the environment
Blindsight
-Damage to primary visual cortex
-No conscious awareness (explicit perception) of visual objects in damaged visual field
-Able to implicitly respond to questions about objects presented in the damaged visual field
-Can perceive something without ‘consciousness’ or awareness
The dorsal ‘where’ pathway
-Spatial information
-Depth perception
-Movement + direction of objects
Akinetopsia
-Damage to dorsal pathway
-Selective motion blindness : cannot see motion. Instead, perceives motion as a series of stationary objects
-Appears as freeze-frames
Optic Ataxia
-Damage to dorsal pathway
-Symptom of akinetopsia
-Inability reaching for objects
-Selective damage leads to problems with certain types of movement
Visual Agnosia
-Difficulties recognizing everyday objects
-Often from damage to the lateral occipital cortex
-Difficulties can be selective to visual categories (faces)
Prosopagnosia
-Fusiform face area (FFA) damage leads to a selective deficit in recognizing faces, keeping intact the ability to visually recognize other objects
-E.g. can’t pick out picture of mother from 4 pictures
-Cues = clothes
Apperceptive Agnosia
-A failure to recognize objects due to problems with perceiving the elements of the objects as a whole
-Problems with perception and discrimination of objects
-Impairment is in grouping visual features to form perceptions that can interpreted as meaningful
Associative Agnosia
-An inability to asociate visual input with meaning
-Problems on tests that require accessing information from memory
-Problems perceiving what their seeing and linking information together
Pattern Recognition
-Perception involves processing basic visual features of an input
-We add up these features and match it to existing patterns (concepts) stored in memory
Feature Detection
-Visual input is broken down into individual parts (features)
- Each feature is processed seperately
-The combination of features is used as a pattern for recognition (probe)
-Compare to something from memory
Template Matching Theory
-Every object has a ‘template’ in long-term memory
-E.g. you see a picture of a bird you’ve never seen before, but you’re able to recognize it’s a bird
-E.g. 4 pictures of Taylor Swift
Prototype Theory
-A prototype is the average representation of an object concept
-Recognition is determined not by literal match, but to a prototype
-Allows for ‘flexible’ object identification
-E.g. visual input (probe) = cog dog, take its basic features and compare them to you’re prototype of a dog to know it’s a dog
Scene Consistency Effect
-The probability of an object appearing in a context is called scene consistency, with a consistent scene corresponding to a high probability while an inconsistent scene corresponding to a low probability
-E.g. identifying a pine cone in a forest vs. identifying a pine cone in a bathroom
