MIND:%20The%20Cognitive%20Side%20of%20Mind%20and%20Brain

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MIND The Cognitive Side of Mind and Brain

• the mind is not the brain, but what the brain
  does (Pinker, 1997)

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COGNITIVE PSYCHOLOGY emerged late 1960s

• The scientific study of higher mental processes,
  from perception and action through memory,
  language, thinking, and problem solving. These
  mental activities involve the processing of
  information.

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COGNITIVE PSYCHOLOGY

• GOAL To understand how the mind works
• METHODS Based on scientific experimentation
• EXPLANATION Focuses on the nature of mental
  representations and the processes that operate on
  them

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INFORMATION PROCESSING METAPHOR

• Both brain and computers process information
• Information (knowledge, representation, symbols)
  is independent of the physical medium

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COGNITIVE SCIENCE Interdisciplinary study of the
mind emerged late 1970s

• Cognitive Psychology
• Artificial Intelligence
• Neuroscience
• Linguistics
• Philosophy
• Anthropology

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NEUROSCIENCE

• GOAL To understand how the brain works
• METHODS Based on scientific experimentation
• EXPLANATION Focuses on nervous system function
  and performance

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Cognitive Psychology and Neuroscience Together

• Initially, interest, but little direct contact
• Two sides of a coin burning a candle at both
  ends
• Very difficult to map cognitive level of
  explanation onto brain
• Today, the cumulative advances in our scientific
  knowledge and technology have opened new
  possibilities for collaboration.

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Cognitive Psychology provides

• Logical analysis of the mental structures and
  processes presumed to be involved in the
  performance of many tasks (task analysis).
• This analysis used to develop cognitive tasks to
  assess aspects of perception, attention, and
  memory.
• Models of mental structures and processes of
  human perception, attention, memory, etc. based
  on data obtained from solid experimental
  procedures

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Cognitive Psychology and Neuroscience

• 1990s Neuroimaging studies demonstrate
  activation of specific brain areas when people
  perform classic cognitive tasks.
• 2000s Some neuroimaging studies help distinguish
  between alternative theoretical accounts of
  cognitive performance.

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COURSE OVERVIEW

• Visual Perception We are visual animals
• Visual Attention We select some, but not all,
  stimuli for processing
• Visual Awareness We are conscious of some, but
  not all, experiences

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PERCEPTION

• Ramachandran video
• Phantom limb, blind sight, unilateral neglect,
  Capgras syndromes reveal that visual perception
  is not the same as sensation.

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IMPOSSIBLE OBJECTS

• Objects to right initially look like coherent
  objects, but they are not physically possible.
• Vision does not simply register what is present.
  It actively constructs percepts

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VISUAL PERCEPTION

• ACTIVE INTERPRETATION of sensory input
• We perceive the world through the filter of our
  knowledge and experience

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Consider THIS ROOM from the perspective of

• Our eyes
• Pre-school child Moose
• Moose

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VISUAL PERCEPTION

• GOAL To understand the 3D structure of the world
  around us by identifying
• What objects are out there
• Where they are located
• What they are doing

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Recognizing Things

• Single Objects
• My mug in different places, orientations,
  lighting conditions changes location, size.
• Letters Words
• Type fonts, all other above variations.
• Faces
• Different views (frontal, side), all other above
  variations

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Three Levels of Perceptual Identification

• Superordinate Fruit
• Entry level Apple
• Subordinate Granny Smith Apple
• Sensory input identified at the level appropriate
  for the task at hand If we want to eat an
  apple, we identify the object as an apple, not as
  a fruit or a Granny Smith apple.

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Stages of Processing A Generic Symbolic Model
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Stages of Processing

• Each stage (i.e., box) is a different level of
  processing.
• Two classes of processes
• Bottom-up (data-driven, sensory-driven)
• Top-down (conceptually driven)

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Dimensional analysis

• A large set of detectors operating in parallel
  to code edges, color, movement (covered in
  lectures on Chapters 1 and 2).
• Analyzers operate in parallel.

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Figure Construction Mechanism

• Organizes the image by segmenting (parsing) it
  into parts and grouping the parts appropriately.
• How do we know which parts go together in the
  figure to the right?

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Figure Construction Mechanism

• Organizes image by binding attributes together
• Gestalt Principles of Grouping
• Multiple glimpses, binocular disparity
• Shape from shading, depth from texture

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Figure Construction Mechanism

• Organizes image by determining what is figure
  (that which we attend to) and what is ground.
• Ambiguous figures two equally good figures
  constructed, as in the Necker cube.

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Perceptual Representation and Comparison
Mechanism

• Perceptual Representation The organized
  percept, ready for identification.
• The perceptual representation is compared to our
  stored shape knowledge (i.e., shape
  representations) by the Comparison Mechanism.

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Top-down Influences

• Local context and our expectations influence
  perception.
• We do not yet know how early in visual
  processing top-down influences of context operate.

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Definitions

• Bottom-up processing (BU) The sequence of
  mental events is largely determined by the
  pattern of incoming information.
• Top-down processing (TD) The sequence of mental
  events is influenced by our knowledge and
  expectations.
• In perception
• processing initially starts with sensation and
  BU processing.
• thereafter, BU and TD processing occur
  simultaneously.

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VISUAL PERCEPTION

• GOAL To understand the 3D structure of the world
  around us by identifying what objects are out
  there, where they are located, and what they are
  doing.

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Whats next?

• Dr. Carolyn Harley completes coverage of Chapters
  1 2
• Chapter 1 Early Vision Retina and Retinal
  Ganglion Cells, LGN, Primary Visual Cortex
• Chapter 2 From Local to Global Image
  Recognition Color, Motion, Image Segmentation,
  Two Cortical Systems