What is Cognitive Psychology

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What is Cognitive Psychology?
PSYCH 317, Section 005 Maria Kozhevnikov Weds
720 1000 pm Science and Technology I 206
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Cognitive Psychology is concerned with the
internal processes involved in making sense of
the environment, and deciding what action might
be appropriate. These processes include
attention, perception, memory, imagery, language,
problem solving, reasoning, thinking, and so on
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Brief History

• Attempts to understand human mind and human
  performance go back to the Ancient Greeks
  (Decartes, Plato, Aristotle). It all starts with
  Philosophy until the 19th century, when
  experimental psychology has been developed.
• Wilhelm Wundt (1832-1920) and his student (Edward
  Titchener) initiated laboratory methods for
  studying mental operations (feelings, thoughts,
  perceptions) more systematically They use
  introspection as a main research method
• Limitations of introspection gt Behaviorism
  (1920-1950)

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Era of Behaviorism

• Behaviorism claims that you cannot do science
  with introspective data. Psychology needs
  objective data, which are measurable, recordable,
  physical events.
• According to behaviorists (e.g., Watson),
  psychology should restrict itself to examining
  the relation between observable stimuli and
  observable behavioral responses. It ruled out any
  discussion about invisible mental processes
  (until about 1950s).

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• Cognitive Psychology in a Nutshell
• The problem in a nutshell why sometimes your
  reaction is guided by understanding the stimulus
  not but the stimulus itself? You cant predict
  behavior focusing only on the stimulus

• Cognitive modeling of the black (mind) box

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The Roots of Cognitive Revolution
The intellectual developments that paved the way
for Cognitive Psychology began in the 40s.
Behaviorism reached his impasse If we wish to
predict behavior we need to make reference to the
mental world! Noam Chomsky rejected behaviorist
assumptions about language as a learned habit and
proposed instead to explain language
comprehension in terms of mental grammars
consisting of rules. George Millers magic
number Miller summarized numerous studies which
showed that the capacity of human thinking
(short-term memory) is limited. He proposed that
memory limitations can be overcome by recoding
information into chunks.
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• The computer as metaphor

• In response to AI, psychologists began to
  formulate a new approach to study human mind.
• The idea was to explore a particular analogy
  suggested by the work in AI that Mind is to
  brain as program is to computer and that Minds
  are essentially "program like" entities that
  "run" on brains instead of computers.

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Cognitive Revolution

• As a result of the paradigm shift often referred
  to as the "cognitive revolution," information
  processing has now replaced Behaviorism as the
  dominant force in psychology (meeting at MIT,
  1956).

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Weaknesses of bottom-up explanations

• Fail to account or many perceptual phenomena

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Top-down and bottom-up processing

• Bottom up data driven, data-based processing
  most (all) of the required information comes from
  the sense organs
• Top down conceptual driven knowledge-based
  processing most (all of the required information
  comes from the mind

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RAT
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Man
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Conclusions

• Most of the information comes from the mind
• From conceptual knowledge previous experience,
  known facts
• From contextually cues
• This allows the poor quality information provided
  by the senses to be given meaning

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Limitations of the computer metaphor
The strong evidence for parallel processing
reveals a major limitation in the simpler version
of information-processing approach, according to
which all processing is serial.
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What is Cognitive Science?

• Cognitive Science is an interdisciplinary field
  that has arisen at the intersection of a number
  of existing disciplines. The shared interest that
  has produced this coalition is understanding the
  nature of the mind.

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Disciplines of Cognitive Science
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Cognitive Science Multiple levels of
descriptions

• The activities of the nervous system can be
  analyzed at different levels
• Psychological (goals and strategies)
• Computational or symbol processing (program
  level)
• Biological/Neurological hardware of the mind
• All the levels are relevant and are not reducible

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Cognitive Psychology

• Information in the brain how it is coded,
  represented, and processed?
• (mostly program level computations and symbol
  processing)

• Perception
• Categorization
• Representation
• Memory
• Attention
• (Language)
• Learning
• Thought

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Four main research methodologies used in modern
Cognitive Psychology

• Experimental cognitive psychology
• Involves carrying out experiments on healthy
  individuals, typically under lab conditions
• Cognitive neuropsychology
• Involves studying patterns of cognitive
  impairment shown by brain-damaged patients to
  provide information about normal human cognition
• Computational cognitive science
• Involves developing computational models
• Cognitive neuroscience
• Involves brain-imaging techniques to study
  aspects of brain functioning and structure
  relevant to human cognition

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Research Methods in Experimental Cognitive
Psychology

• Controlled laboratory experiments
• Characterization
• An experimenter conducts research in a laboratory
  setting in which he/she controls as many aspects
  of the experimental situation as possible
  (measure primarily RT and Error Rate)
• Advantages
• Enables isolation of causal factors
• Excellent means of testing hypotheses
• Disadvantages
• Often lack of ecological validity, provide no
  direct evidence of brain functioning, ignore
  individual differences

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Research Methods in Cognitive Psychology and
Cognitive Neuropsychology

• Cognitive neuropsychology is concerned with the
  patterns of cognitive performance shown by
  brain-damaged patients.
• The essence of cognitive neuropsychology is
  building a theory about normal cognition from
  study of abnormal cognition.

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Lesion Studies

• Damage to a particular part of the brain can
  result in specific behavioral effects (assumes
  functional and anatomical modularity)
• Examples
• Amygdala (emotion)
• Hippocampus (memory)
• Parietal cortex (attention)
• Left hemisphere (language)

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Neuropsychology Methods

• Single dissociation
• Patient with lesion in brain region A
• Performs well on task A
• Performs poorly on task B
• Inference brain region A mediates performance on
  task B but not task A

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Neuropsychology Methods

• Problems with single dissociations?

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Neuropsychology Methods

• Double dissociation
• Patient with lesion in brain region A performs
  well on Task A and poorly on Task B
• Patient with lesion in brain region B performs
  well on Task B but poorly on Task A
• Inference Brain region A mediates Task B Brain
  Region B mediates Task A

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Research Methods in Cognitive Psychology and
Cognitive Neuropsychology

• Disadvantages
• Brain damage is usually extensive, can cover more
  than one module
• The impact of brain damage on cognitive
  functioning may be camouflaged since patients
  develop compensatory strategies
• Individual differences

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Research Methods in Computational Cognitive
Science

• Computational modeling involves development of
  descriptive or mathematical models of cognitive
  functioning or computer simulations
• Production systems, which consists of pf
  productions in the form of IF THEN rules
• Connectionist networks

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• Connectionists models
• Connectionist models can model complex behaviors
  without recourse to large sets of explicit
  propositional rules
• Connectionist models represent information
  without recourse to symbolic codes like images or
  propositions, they are said to represent
  information sub-symbolically

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Distributed representations The sight and scent
of a rose
The sight and scene of a rose from
connectionist perspective is represented as the
connections strength between neuron-like units
that will allow either the scent or vision of the
rose to be recreated
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The sight and scent of the rose can be viewed as
being coded in terms of simple signals in certain
input cells (pluses and minuses)
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• Connectionist networks (Continued)
• A representation of a concept can be stored in a
  distributed manner by a pattern of activation
  throughout the network
• The same network can store many patterns without
  them necessarily interfering with each other
  Sight and smell of steak is represented by a
  different vision and olfactory patterns.

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Key Themes in Connectionist Networks

• Computation without explicit rules and
  representations
• no distinction between data structures and rules
  (programmes) that operate on them

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Problems with Connectionism

• Fail to capture the scopes of mental phenomena
  (e.g., cannot take into account motivational or
  emotional factors) or explain complex reasoning
  and problem solving processes.

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Research Methods in Cognitive Neuroscience
http//www.youtube.com/watch?vOaT3f1B6PJY
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Electroencephalography (EEG)

• Brain produce electricity (neurons do their
  business by acting like wires)
• Electrodes placed on scalp record brain
  electrical activity
• Measures include an amount of activity in a
  particular frequency band such as power and
  activation (alpha, beta, gamma, theta, delta)

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Wireless EEG System Powered By Body Heat
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Event-related Potential (ERP)

• Brain-related activity that comes from
  simultaneous firing of synapses and is related to
  a specific event
• How do you measure them? Electrodes placed on
  scalp record brain electrical activity
• Activity is recorded in response to a specific
  event and averaged across about 50 trials

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State-of-the-Art ImagingPET, fRMI
Areas of brain activated during memory task
Activation of primary visual cortex as a whirling
pattern is viewed
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Positron-emission tomography (PET)
Typical positron emission tomography (PET)
facility
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Functional Magnetic Resonance Imaging (working
memory)
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Recently, it has become possible in recent years
to use magnetic and positron as well as EEG/ERP
recording scanning devices to observe what is
happening in different parts of the brain while
people are doing various mental tasks.
EEG/ERP recording
MRI (axial)
fMRI (coronal)
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Cognitive Neuroscience in a broad sense

• Experimental cognitive psychology
• Cognitive neuropsychology
• Computational cognitive science
• Cognitive neuroscience
• This integrative approach is often referred to as
  COGNITIVIE NEUROSCIENCE in a broad sense

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Four lobes of the cerebral cortex
Ventral (at the bottom) dorsal (on top)
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Two hemispheres of the brain
Lateral at the side
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Medial section of the brain
Medial in the middle