Docstoc

Introduction to Cognitive Science - PowerPoint - PowerPoint

Document Sample
Introduction to Cognitive Science - PowerPoint - PowerPoint Powered By Docstoc
					Introduction to Cognitive
        Science



        COGS 590- Images from Ashcraft, Sobel,
                Stillings and Thagard
                 Outline
   Definition and Scope of Cognitive
    Science
   A Brief History and Overview of
    Major Concepts
   Multidisciplinarity
   Introducing Contributing Disciplines
   Concluding Remarks- How to Become
    a Cognitive Scientist?
     What IS Cognitive Science?
   The interdisciplinary study of mind and
    intelligence.
   Study of cognitive processes involved in
    the acquisition, representation and use of
    human knowledge.
   Scientific study of the mind, the brain, and
    intelligent behaviour, whether in humans,
    animals, machines or the abstract.
   A discipline in the process of construction.
               Cognition
   Cognition – from Latin base cognitio
    – “know together”
   The collection of mental processes
    and activities used in perceiving,
    learning, remembering, thinking, and
    understanding, and the act of using
    those processes
       Intelligence vs. Cognition

   The goal of cognitive science:
    develop a theory of Intelligent
    Systems?
   The goal of artificial intelligence:
    passing Turing Test?
Disciplines in Cognitive Science
   Philosophy
   Neuroscience
   Computer Science- Artificial
    Intelligence
   Psychology – Cognitive
    Psychology
   Linguistics
   Anthropology, Education
    Relatively Recent Challenges
   Not only Connectionist but dynamic and
    statistical models of cognition: e.g.
    versions of Optimality Theory in
    Linguistics
   Increasing role of neuroscience
    • On philosophy of mind – Churchlands
    • Emergence of new subdisciplines: cognitive
      neuroscience, computational neuroscience
   Embedded, situated cognition
    • Cognitive anthropology, cognitive informatics
   Tackling hard subjects
    • Consciousness
          Cognitive Processes
   Learning and Memory
   Thinking and Reasoning (Planning,
    Decision Making, Problem Solving ...)
   Language
   Vision-Perception
   Social Cognition
   Metacognition
   Emotions
   Dreaming and Consciousness
     History of Cognitive Science
   Cognitive Science has a very long past but
    a relatively short history (Gardner, 1985)
   Philosophy: rationalism (Plato, Descartes,
    Kant, ...) vs empiricism (Aristotle, Locke,
    Hume, Mill, ...)
   Cartesian Dualism
   Putnam – functionalism (60s); Fodor (70s)
    Language of Thought hypothesis
Behaviourism and Cognitive
         Science
    History of Cognitive Science
   Against Behaviourism: Watson,
    Skinner “psychology as a science of
    behaviour”
   The Cognitive Revolution – Chomsky,
    Miller, Bruner, Putnam, Newell,
    Simon, McCarthy- 1950s
   Contributing research paradigms:
    Cybernetics, Gestalt Psychology
     History of Cognitive Science
   Cognitive Psychology
    • First textbook by Neisser in 1967
    • Advances in memory models (60s)
   Artificial Intelligence
    • Newell and Simon – Logic Theorist, GPS
    • McCarthy – frame problem
    • Minsky
     History of Cognitive Science
Neuroscience:
   Brain structure and function (Gall, Spurzheim)
   Phrenology-late 19th century
   Localization of function: Wernicke, Broca
   Neural impulse: Helmholtz
   Complexity of the human cortex: Lashley,
    Penfield
   The Man who Mistook his Wife for a Hat-a case
    for prosopagnosia
   Neural Network Modeling in 1950s: Pitts and
    McCulloch, Hebb, Rosenblatt
    History of Cognitive Science
   Linguistics:
    • Saussure- late 19th century, on
      structure of language
    • Bloomfield, Sapir: behaviourist
    • Zellig Harris and Chomsky: language as
      a generative system- innateness
    History of Cognitive Science
   Birth date: Symposium on
    Information Theory at MIT in 1956-
    Participants: Chomsky, Newell,
    Simon, Miller...
   Cognitive Science journal in 1977
   Cognitive Science society in 1980
   Around 200 Cognitive Science
    programs worldwide in 1995.
       Is cognition information
             processing?
   Church-Turing Thesis
   Universal Turing Machine
   The information-processing
    metaphor: data+ algorithms
   Searle’s Chinese Room Argument
Paradigms of Cognitive Science
   Computational Representational
    Understanding of Mind
    • Computational Theory of Mind
    • Cognitivism, Functionalism
   Symbolicism – Connectionism-
    Dynamicism - Hybrid approaches
Research Programme of
  Cognitive Science
    Methods of Cognitive Science
   Experimentation (psychology, linguistics,
    neuroscience)
   Computational Modeling (artificial
    intelligence, computational neuroscience)
   Introspection, Argumentation, Formal
    Logic and Mathematical Modeling
    (philosophy, linguistics)
   Ethnography (cognitive anthropology)
Evaluating cognitive theories

•    Psychological plausibility
•    Neurological plausibility
•    Representational-computational power
•    Practical applicability (education,
    design, intelligent systems)
    Multidisciplinarity in Cognitive
               Science
   (Schunn et al, 1998) study on Journal
    Cognitive Science and Cognitive Science
    Society Meetings : computer science and
    cognitive psychology dominates.
   Multidisciplinarity esp. impact of
    neuroscience on the growth
   Still only 30-50% of the work are
    multidisciplinary
   Nature of multidisciplinary collaborations
    differ
       Localist or Holist View of
           Multidisiplinarity
   (Von Eckardt, 2001) A field is
    multidisciplinary if individual research
    efforts are multidisciplinary-localist view
   A field is multidisciplinary if multiple
    disciplines contribute to the execution
    to its research program (elaborate layered
    set of goals directed at the main goal)-
    holist view
    Unified Theories of Cognition
   Unify-the aim of science.
   “... positing a single system of
    mechanisms- a cognitive architecture-
    that operate together to produce the full
    range of human cognition.” (Newell, 1990)
   Bring all parts together.
   Increase rate of cumulation of knowledge.
   Increase applicability.
   Approximate, rather than discriminate.
   Not everyone agrees this is how cognition
    should be studied.
             Neuroscience
   Neurocognition, cognitive
    neuroscience, cognitive
    neuropsychology: Study of
    neurological basis of cognitive
    processing
   Computational neuroscience:
    Detailed simulation of neuronal
    mechanisms
             Nervous System
   Peripheral (nerve fibers, glands) vs.
    Central nervous system (brain, spinal
    cord)
   Brain: Cerebral cortex vs. Subcortical
    areas, such as the limbic system
   Two hemispheres (left-right); four lobes
    (frontal, parietal, occipital, temporal)
Human Brain
                Neurons
   Major cell type in the nervous system
    (other: glial cells)
   About 50- 100 billion neurons (1011 )
    connectedness (typical fanout 103)
   Different types of neurons
   Different types of synapses
Structure of a Neuron
             Neurons (cont).
   Resting membrane potential vs. Action
    potential (fire!) : concentration of ions
   Electrical synapses vs. Chemical synapses
   Excitatory vs inhibitory
   Neurotransmitters and neuromodulators
   Acetylocholine, dopamine, serotonin-
    around 30 known
   Role of reentrant pathways
    Contralaterality and Cerebral
            Laterization
 Visual system       Visual system
  letters, words       faces, complex
 Auditory system      patterns
  language related    Auditory system
  sounds              music
 verbal memory
                      nonverbal memory
 speech, reading,
                      prosody?
  writing
                      Spatial processes
LEFT H.
                     RIGHT H.
      Methods of Investigation-I
   Structural techniques: CAT scan
    (Computer Axial Tomography); MRI
    (Magnetic Resonance Imaging)
   Functional techniques: PET scans
    (Positron Emission Tomography);
    fMRI (functional MRI)
   Temporary lesions-> TMS
    (Transcranial Magnetic Stimulation)
PET Scans
     Methods of Investigation-II
   Electrophysiological Techniques:
    • EEGs (Electroencephalograms)
    • ERPs (Event Related Potentials)
   Used in combination with
    neuroimaging techniques
   Used in conjunction with behavioural
    methods
EEG s and ERPs
       Methods of Investigation
   Case and Lab Studies of Various
    Disorders
   Acquired vs developmental deficits
    • Dyslexia, autism
    • Agnosia, aphasia, amnesia
   Other disorders, e.g. schizophrenia
      Cognitive Psychology
 Perception, Pattern Recognition
 Attention

 Skill Acquisition, Learning

 Memory

 Language

 Reasoning and Problem Solving

Experimental Methods, Simulation
                   Linguistics
   Linguistic Universals
   Grammar as a Descriptive System
    • Explaining productivity, e.g. This is the cheese
      that lay in the house Jack built
   I-language & E-language
   Universal Grammar
   Major theories of Grammar (such as
    Minimalist Program, Construction
    Grammars etc) have different cognitive
    claims
    Major Components of Analysis
   Phonology        Discourse
   Morphology       Pragmatics
   Syntax
   Semantics
       Cognitively Important
    Subdisciplines of Linguistics
   Psycholinguistics
    • Language Acquisition
    • Discourse Comprehension and Memory
   Neurolinguistics
   Computational Linguistics
         Artificial Intelligence
   Study of intelligent behaviour
   Automation of intelligent behaviour
   Machines acting and reacting
    adaptively
   How to make computers do things,
    which humans do better
   Study and construction of rational
    (goal and belief-directed) agents
Modeling for Study of Cognition
   Strong AI (duplicating a mind by
    implementing the right program) vs Weak
    AI (machines that act as if they are
    intelligent)
   aI (the study of human intelligence using
    computer as a tool) vs Ai (the study of
    machine intelligence as artificial
    intelligence) (Yeap)
   Artificial Intelligence and Cognitive
    Science: a history of interaction
    Advantages of Computational
             Modeling
   Push predictive aspects of a theory:
    more formal, precise and abstract
    specifications
   Computer programs are good
    experimental participants
   Unify several different classes of
    facts as compared to hypothesis
    testing
Philosophy in Cognitive Science
   Philosophy of Mind
   Philosophical Logic
   Philosophy of Language
   Representations (Ontology)
   Knowledge and belief (Epistemology)
   Defining the scientific enterprise of
    cognitive science (Philosophy of science)
   Metaphysics, Phenomenology
        How to Become a Cognitive
                Scientist?
   No hard and fast answers, possible heuristics only
   Develop critical (and fast) reading skills and apply them
    broadly across a number of areas of cognitive science
    • Be as general and as objective as possible in the beginning of
      your studies: read, read and read.
    • If possible, form a regularly meeting reading group (can be a
      general cognitive science reading group or a special interest
      group).
    • Develop practical experience of different methods in cognitive
      science as much as possible.
    • Read past theses of this department and possibly of other
      cognitive science departments; use the handout as starting
      point for extra readings. Get reading lists of PhD specialization
      exam.
    • Specializations and indepth expertise comes later, may be in
      your PhD studies. Do not look upon your Master’s work as final
      but as foundational.
         Concluding Remarks
   All these will take time; be patient;
    do not get discouraged.
   Take relief in that you are getting
    into a very, very interesting
    discipline.
   Pay attention, not only to the
    results-such as grades- but to the
    processes of becoming a Cognitive
    Scientist.

				
DOCUMENT INFO