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Transcript
Information Processing Model of
Cognition
• First Meta-theory in cognitive science – a
all encompassing theory designed to
explain cognition
1
The Use of Models
• Hydraulic models of human behavior- Romans
believed the heart pumped fluids that caused
movement
• Descartes – mechanical model, the body
functions like a machine
• British empiricists- model base upon physics
• Associationists – model based upon chemistry
• 1950’s computer model – information processing
model
• 1980 brain model - connectionism
2
7 Themes of Cognition
• Attention – different types are important
• Automatic and conscious processing
• Data driven versus conceptually driven
processing
• Representations – how memories are stored
• Implicit versus explicit memory
• Metacognition
• The Brain
3
Research Methods Used
• Correlational studies – are two or more
factors or variables related
• Experimental studies – manipulate one or
more variables and control others
• Quazi-experimental – the variable of
interest cannot be manipulated, usually
involves subject variables
• Single case – use of one subject – most
frequently used in neurocognition
4
Methods for Measuring Cognition
• 1. Reaction time – measure time between
stimulus and response
• 2. Accuracy measurements
– Simple – how many mistakes were made
– Complex – look for a pattern of errors
• 3. Trials to criterion
• 4. Relearning – learn a task. After a delay
how long did it take to relearn the task
5
Guiding Analogies
Channel Capacity:
An early analogy for the limited capacity of the
human information-processing system.
The Computer Analogy:
Human information processing may be similar to
the sequence of steps and operations in a
computer program, similar to the flow of
information from input to output when a
computer processes information.
6
The Atkinson and Shiffrin Model
The Atkinson and Shiffrin Model of Human Memory
Encoding: The act of taking environmental stimulation and
converting it to a usable mental form (electrical signals).
• Three memory components: sensory memory, shortterm memory, and long-term memory.
7
Examples
• Multiplying 2 X 3 =
• Lexical Decision Task: A timed task in which
people decide whether letter strings are or are
not English words.
– Takes longer to decide if a non-word is real than a
real world
– Word Frequency Effect: The effect which states that it
takes significantly longer to judge words of lower
frequency than it does to judge high-frequency words.
8
The Strict Information Processing
Approach
• Sequential Stages of Processing: An
assumption in most process models that the
separate stages of processing occur in a fixed
sequence, with no overlap of the stages.
• Independent and Nonoverlapping Stages: The
assumption in the strict information processing
approach that the stages of processing are
independent of one another in their functioning,
and that they do not overlap in time.
9
Some Problems
• Parallel Processing: Any mental
processing in which two or more
processes or operations occur
simultaneously.
• Model could not explain how context could
speed up processing such as during
priming tasks
10
The Modern Cognitive Approach:
Cognitive Science
11
Cognitive Science
• The study of human thought, using all
available scientific techniques and
including all relevant scientific disciplines
for exploring and investigating cognition.
12
Updating the Standard Theory
13
Two Types of Processing
• Bottom-up or data driven
• Top-down or conceptually driven
14
Summary
The strict-information processing approach to
cognition was replaced with a broader, more
inclusive approach now known as cognitive
science. This approach described cognition as
the coordinated, often parallel operation of
mental processes within a multicomponent
memory system. The approach is deliberately
multidisciplinary, accepting evidence from all the
sciences interested in cognition.
15
Brain Anatomy
16
Brain Anatomy (con’t.)
• Neocortex or cerebral cortex: The top
layer of the brain responsible for higherlevel mental processes.
– The lobes of the neocortex: the frontal lobe,
parietal lobe, occipital lobe, and temporal lobe
17
Four Lobes of the Neocortex
18
Lower Brain Structures
19
Brain Anatomy (con’t.)
Three other subcortical (below the neocortext) structures
are especially important to neurocognition:
thalamus: the gateway to the cortex; almost all messages
entering the cortex come through the thalamus
corpus callosum: the primary bridge across which messages
pass between the left and right halves or hemispheres of the
neocortex
hippocampus: an internal brain structure strongly implicated
in the storing of new information into long-term memory
20
Principles of Functioning
• Contralaterality: The principle that control
of one side of the body is localized in the
opposite-side cerebral hemisphere.
• Hemispheric Specialization: The principle
that each cerebral hemisphere has
specialized functions and abilities.
21
Split-Brain Research and
Lateralization
• Research on split-brain patients
• Principle of lateralization
22
Basic Neurology
• Neurons: The basic building block of the
brain and the entire nervous system, a
neuron is a cell that is specialized for
receiving and transmitting a neural
impulse.
23
The various structures of the
neuron
24
Basic Neurology (con’t.)
• Synapses: The region where the axon
terminals of one neuron and the dendrites
of another come together is the synapse.
• Neurotransmitter: The chemical
substance released into the synapse
between two neurons, responsible for
activating or inhibiting the next neuron in
sequence.
25
Methods of Investigation
• Lesions: Used by Sperry; the site and extent of
the brain lesion are important guides to the kind
of disruption in behavior that is observed and
vice versa.
• Direct Stimulation: Pioneered by Penfield; the
patient in brain surgery remained conscious
during surgery and was administered minute
electrical charges to the exposed brain, thus
triggering very small regions.
26
Exposed cortex of one of Penfield’s
patients
27
Methods of Investigation (con’t.)
• Imaging Technology
• Magnetic Resonance Imaging (MRI): Gives clear
pictures of the structure of the brain.
• Functional MRI: Image shows regions of the brain
with heightened neural activity, with different colors
reflecting high or low levels of blood flow, oxygen
uptake, and the like.
• PET scans- use or radioactive labels attached to
glucose
28
Methods of Investigation (con’t.)
• Electrocephalograms (EEG): Electrodes
are attached to the subject’s scalp, and
the device records the patterns of brain
waves.
• Event-Related Potentials: The
momentary changes in electrical activity of
the brain when a particular stimulus is
presented to the subject.
29
30
Neural Net Models: Connectionism
• Connectionist models are often called
neural net models or parallel distributed
processing (PDP) models; the three terms
are synonymous. All refer to a computerbased technique for modeling complex
neural based systems.
31
An early connectionist model by
McClelland and Rumelhart
32