1

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’ …. ?

2

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

3

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

5

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

6

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’

7

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?

8

1950’s computer

• Limited memory

• Limited processing capacity

• Narrow pipe for moving information from memory to the processor

1950’s cog. psych mind

• Limited STM capacity

• Limited central executive

• Narrow attention channel for moving information from STM to cent. Exec.

Kinda similar, huh?

9

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

10

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

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• “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

14

• “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)

15

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