What is the big picture?
• Why study cognitive
psychology?
– A lot of this stuff you’ve already
seen – eg Freud went on and on
about memory & forgetting
– What makes cognitive
psychology worth studying?
• What is cognitive psychology,
anyway?
– ‘psychology that thinks people
are computers’ …. ?
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Cognitivism – a big deal
• In the computer age, ‘thinking’
is no longer a big deal
– Computers do maths, search for
stuff, sort our email…
– Your microwave decides how to
cook your chicken
• Before 1935 or so, thought was
something only humans did
– World War 2 changed that
• The philosophy that thought
can considered as independent
of a thinker is called
cognitivism
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A brief history of thought
• In ancient times, thought was
associated with divinity
– ‘created man in his image’
• The idea that thought is
‘special’ or ‘magical’ continued
into mainstream psychology in
the 20th century
– Freud: the mind is mysterious,
bound to human biology
– Maslow: thought is bound to the
human condition
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– Skinner: the mind is an
inscrutable ‘black box’ which
causes stuff to happen
• Around 1935, mathematicians
looked mathematical functions
which can evaluate other
functions
– Alan Turing and Alonzo Church
worked on this problem
– Resulted in Turing Machines,
which can follow a set of
instructions
4
Thinking machines? What?
• Philosophically,
caused an
outrage
– Surely this
wasn’t real
thought the
way people do
it?
•The debate was halted by World
War 2
•German engineers
developed the Enigma
Machine, a machine to
encode messages
•Allied mathematicians were tasked
with breaking the code – had to
perfect computers to do it
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After the war
• Once the war was over, thinking machines
were all over the place
– IBM calculators
– Cannon aiming computers
– Each capable of a specific task
• The search was on for a general purpose
computer
– A good solution was provided by John von
Neumann
– ‘the von Neumann architecture’
6
Enter Don Broadbent
• Broadbent asks the question:
“what if we imagine that the
mind is like a computing
machine?”
– He applies von Neumann‘s
architecture to human
psychology
– Important moment in
psychology: thought loses its
magic; it can now be understood
completely, from a mathematical
and engineering point of view
– Not saying the mind is a
computer – just asking, what if it
were?
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1950’s
computer
1950’s cog.
psych mind
• Limited
memory
• Limited STM
capacity
• Limited
processing
capacity
• Narrow pipe
for moving
information
from memory
to the
processor
• Limited
central
executive
• Narrow
attention
channel for
moving
information
from STM to
cent. Exec.
Kinda similar, huh?
8
Quite a useful way to think
• You can get quite far by asking
that question
– “if the mind were like a computer,
then it should….”
• Slowly, piece by piece, you can
imagine a computer that works
just like the mind does
– Shows the same strengths,
makes the same mistakes
– This type of imaginary computer
is called a model
– Modelling is one of the main jobs
of cognitive psychologists
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Notice the change
• We have gone from Freud:
– “The mind is made of three
parts, and it has an energy
called libido”
• To the cognitive psychologist
– “The mind works as if it had a
central processor that were
connected to a central store by a
limited size bus”
• Not concerned about how it is
as much as how it works
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Criticisms of cognitive
psychology
• “Cognitive theory is too cold
and inhuman – it cannot take
into account emotion”
– Not that it cannot rather than it
does not
– Some people research only the
role of emotion on cognition
•
•
•
•
Anxiety and attention
Depression and cognition
‘Mood congruence’
Wide clinical application (e.g.
catastrophic thinking)
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• “Cognitive psychology is too
pessimistic about humans; it
presents us a machines or
zombies”
– Since when is
pessimism/optimism a measure
of a good theory?
• Would you like a ‘nice’ theory or a
useful one?
– Thinking as if humans were
machines is very useful
• You can predict human behaviour
(to an extent)
• You can then apply your knowledge
• Better computers, can help people
from forgetting stuff, etc
12
• “Cognitive psychology presents
us as machines, and thus
denies the importance of free
will”
– No cognitive psychologist would
deny that free will is an aspect of
human psychology
– Not that it is denied – haven’t
figured out how it fits in yet
– Any theory which is completely
deterministic would be hard for
most cognitive psychologists to
swallow
13
• “Cognitive psychology does
take into account effects of
ideology on human
psychology, and ignores power
differences between
researcher and subject”
– No theory can take everything
into account – marxist theory
doesn’t take people’s
expectations into account either!
– Cognitive psychology works at a
different level of analysis –
wrong to declare a theory wrong
because it doesn’t work like your
favorite (fallacy of misplaced
essentials)
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The next step:
Cognitive Science
• During the 1980s, a new
discipline started appearing
– Computer science, artificial
intelligence, neuroscience &
cognitive psychology teamed up
– Study thinking machines as
separate from the
implementation
– Application: improve knowledge
about humans, and leads to
better computers
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