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low-level processing (Visual perception (parallel processing (PPT 17)…

- - - - photoreceptors: rods
        
        sensitive to low levels of light - night vision/ color-blind
      - photoreceptors: cones
        
        less sensitive & need more incoming light - day light vision; but sensitive to different wavelengths - color vision; discern fine details - acuity
      - Fovea (dead back of eye) & blind spot (optic nerve leave the eye)
      - photopigment of rods and cones break downs & transduction
    - - lens
        
        can change shape to let light land perfectly on the retina
      - cornea
        
        refract: shape of cornea cause light to bent / refract
  - - - cells when stimulated, inhibit the activity of neighboring cells - moderate level of activity in cell
    - - highlighting the information that defines an object's shape (mach bands)
  - - - sensitive to direction and speed of movement
    - - primary visual cortex, they fire maximally to bar in different direction (also called BA17/ stratecortex)
        
        One neuron responses to larger part of the world, Origin in the world the cell fire to; 2. more complex it gets; 3. two different pathways
    - - fire strongly when the input is a certain color and a certain shape
    - - P cells: LGN's parvocellular cells
        
        brightness, spatial analysis & detailed analysis of form (most cones map to )
      - M cells: margnocellular cells
        
        detection of motion and the perception of depth (most rods map to )
    - - what system
        
        identification of visual objects (temporal lobe) Ventral Stream (analysis of form and color), parvo cells
        
        Visual agnosia (inability to recognize objects) - lesions in infero-temporal cortex:
        able to grasp things but can not recognize objects
      - where system
        
        where an object is located (parietal cortex) Dorsal Stream(analysis of motion and spatial relations), margno cells
        
        Optic ataxia(difficulty with visually guided movements) - lesions in parietal cortex: able to identify the object but can not grad the object
  - - - figure-ground segregation (shift from one figure to the other - background or the front)
        
        Gestalt Grouping Principles
        
        law of good continuation - same direction continued
        
        law of closure / completion - close the figures
        
        law of simplicity - interpret ambiguous or complex images as the simplest form possible
        
        law of similarity - same set grouped
        
        law of Proximity - close together
      - context effects(stimulation is neutral, we add meaning to it; stimulation is not changing but our perception is changing)
      - Gestalt psychology - the whole is greater than the sum of its parts
      - subjective contours (PPT 37)
  - - - no adjustment if objects are very far
      - pictorial cues- flat surface (interposition)
      - linear perspective
    - - motion parallax
        
        nearby objects move more than those of distant ones
      - optic flow
        
        approach an object, it gets larger.
- - - - flow of the ambient array specifies locomotion and nonflow specifies stasis (destination)
      - outflow specifies approach and inflow specifies retreat from
      - the focus or center of outflow specifies the direction of locomotion in the environment
      - a shift of the center of outflow form one visual solid angle to another specifies a change in the direction of locomotion, a turn and a remaining of the center within the same solid angle specifies no change in direction
    - - ratio of the ground texture (ppt24: width)
    - - same relative point of horizon intersects (ppt25: 1/3 of the telephone stand with the horizontal line)
      - eye height ratio: our eye height intersects same-sized objects at the same relative point
  - - - binocular disparity: two separate images into the brain - resolve as depth (3d)
      - motion parallax
        
        objects farther - mover more slowly than closer
        
        objects closer - move in the direction opposite to us/ farther - move in the same direction as us
      - interposition / occlusion (one object covers another - closer in depth)
      - linear perpective
      - height in the field
      - aerial perspective - appear hazier tend to be father
      - texture gradient - uniform element of texture
        become smaller and dense with distance
- - - - inability to detect a stimulus when paying attention to else where
    - - daniel kahneman -1973: our capacity for doing mental work is limited, paying attention = allocating these limited resources (depend on environment - you can relax if you are tired)
  - - - dichotic listening: the technique to study selective listening (refer to book)
      - shadowing: repeat the message back - they have monotone voice because it requires lots of effort - so they unaware of message content and they have no idea what they hear on the other ear
      - other four trails (ppt 16)
    - - filtering occurs early based on physical characteristics.
    - - throw one's name in. - they could listen to the number in one ear, and hear their name, then shift the other rest of the numbers in the other ear; context and meaning
    - - sentence fragments - meaning driving our attention - turn down the information when we do not need it - all words are stored but in different levels (names has low threshold of activation)
      - in the middle of rationalism and behaviorism
    - - low-validity
        
        doing lots of trails and show them several primed letters. 20% of the actual test time, primed letter match to the actual letters. 80% misled trail & neutral trail (no real association)
        
        physical characteristics
        
        no expectations so there is no real cost of misled
      - high-validity
        
        20% are misled & neutral and 80% are match
        
        prepare to response: unconsciously create an expectation
        
        faster of benefit of priming & over adjusting of match then if not match (pattern build up to a system and reach the consciousness of the participants) the cost will be more
      - ppt 3 - threshold of neuron firing again is lower if it fires before (primed)
  - - - balint's syndrome (simultanagnosia - related to Optic ataxia): can't see two things at one time; focus on things that they see first; but they can see grouped things
      - hemispatial neglect patient - damage to right parietal lobe and ignore attention to left side of the space - space-based then switch to object-based
- - - - recency of view
      - familarity
    - - feature-network:neurons
      - excitatory connections
      - sensitive to geons (viewpoint-independent)
      - bottom-up: reduce to 12 basic shapes of all the objects in the world - recognizing the part all together, so the orientation doesn't matter
  - - - get the repetition suppression effect only in the left ventral occipital cortex when objects are in different orientation for the second time: left ventral occipital cortex: view-independent - an indication of recognition
      - get the repetition suppression effect only in the right ventral occipital cortex when objects are in same orientation for the second time: right ventral occipital cortex: view-dependent
      - fMRI - bold signal lower: increase neural efficiency / object recognition if we see the object the second time
  - - - holistic processing
      - in general, recognition of objects is better than faces; better of holistic processing of faces than little features
      - the composite effect - when features are put together, we alter the way to process faces
      - opposite views: greebles - faces recolonization is just a common instance of expertise (people can learn by training) FFA did light up; while some people argue that greebles do have some face features