1. by
Col Mukteshwar Prasad(Retd),
MTech(IIT Delhi) ,CE(I),FIE(I),FIETE,FISLE,FInstOD,AMCSI
Contact -+919007224278,
e-mail -muktesh_prasad@yahoo.co.in
for book ”Decoding Services Selection Board” and
SSB guidance and training at Shivnandani Edu and Defence
Academy,Kolkata,India
Cognitive Psychology and
Information Processing in Computers
Ref- Saul McLeod Paper published 2008

2. Information Processing
 At the very heart of cognitive psychology is the idea of information
processing.
 Cognitive psychology sees the individual as a processor of information,
in much the same way that a computer takes in information and follows a
program to produce an output.
 Cognitive psychology compares the human mind to a computer,
suggesting that we too are information processors and that it is possible
and desirable to study the internal mental / mediational processes that
lie between the stimuli (in our environment) and the response we make.
 The information processing paradigm of cognitive psychology views that
minds in terms of a computer when processing information.
 However, there are important difference between humans and computers.
 The mind does not process information like a computer as
computers don’t have emotions or get tired like humans.

5. Environmental
Stimuli
Sensory
Memory
Short-term /
Working
Memory
Long-term Memory
&
Knowledge
Cognitive
Psychology
is concerned with
what goes on in
here.
Overt
Response
Behavior
Info. Processing model

6. Cognitive Psychology
• Information processing approach –
decomposition of mental processes
– Multi-component memory system
• Assumptions of Cog. Psych.
– Mental processes exist
– People are active information processors
– Mental processes and structures can be
revealed by time and accuracy measures

7. Basic Assumptions
 The information processing approach is based on a number of
assumptions, including:
 (1) information made available by the environment is
processed by a series of processing systems (e.g.
attention, perception, short-term memory);
 (2) these processing systems transform or alter the
information in systematic ways;
 (3) the aim of research is to specify the processes and
structures that underlie cognitive performance;
 (4) information processing in humans resembles that in
computers.

8. Computer - Mind Analogy
 The development of the computer in the 1950s and 1960s had an important
influence on psychology and was, in part, responsible for the cognitive
approach becoming the dominant approach in modern psychology
(taking over from behaviorism).
 The computer gave cognitive psychologists a metaphor, or analogy, to which
they could compare human mental processing.
 The use of the computer as a tool for thinking how the human mind
handles information is known as the computer analogy.
 Essentially, a computer
 codes (i.e. changes) information,
 stores information,
 uses information, and
 produces an output (retrieves info).
 The idea of information processing was adopted by cognitive psychologists
as a model of how human thought works.

9. Computer - Mind Analogy..(2)
 For example,
 the eye receives visual information and codes information into
electric neural activity
 which is fed back to the brain where it is “stored” and “coded”.
 This information is can be used by other parts of the brain relating to
mental activities such as memory, perception and attention.
 The output (i.e. behavior) might be, for example, to read what you
can see on a printed page.
 Hence the information processing approach characterizes thinking as
the environment providing input of data, which is then transformed by
our senses.
 The information can be stored, retrieved and transformed using
“mental programs”, with the results being behavioral responses.

10. Computer - Mind Analogy..(3)
 Cognitive psychology has influenced and integrated with many other
approaches and areas of study to produce, for example,
 social learning theory,
 cognitive neuropsychology and
 artificial intelligence (AI).
 Information Processing & Attention
 When we are selectively attending to one activity, we tend to ignore
other stimulation, although our attention can be distracted by something
else, like the telephone ringing or someone using our name.
 Psychologists are interested in
 what makes us attend to one thing rather than another (selective
attention);
 why we sometimes switch our attention to something that was
previously unattended (e.g. Cocktail Party Syndrome), and
 how many things we can attend to at the same time (attentional
capacity).

11. Computer - Mind Analogy..(4)
 One way of conceptualizing attention is to think of humans as information
processors who can only process a limited amount of information at a time
without becoming overloaded.
 Broadbent and others in the 1950's adopted a model of the brain as
a limited capacity information processing system, through which
external input is transmitted.

12. The Information Processing
System
 Information processing models consist of a series of stages, or boxes, which
represent stages of processing.
 Arrows indicate the flow of information from one stage to the next.
 * Input processes are concerned with the analysis of the stimuli.
 * Storage processes cover everything that happens to stimuli internally in the
brain and can include coding and manipulation of the stimuli.
 * Output processes are responsible for preparing an appropriate response to
a stimulus.

14. Critical Evaluation
 A number of models of attention within the Information Processing framework
have been proposed including:
 Broadbent's Filter Model (1958),
 Treisman's Attenuation Model (1964) and
 Deutsch and Deutsch's Late Selection Model (1963).
 However, there are a number of evaluative points to bear in mind when
studying these models, and the information processing approach in
general.These include:
 1. The information processing models assume serial processing of
stimulus inputs.
 Serial processing effectively means one process has to be completed
before the next starts.
 Parallel processing assumes some or all processes involved in a cognitive
task(s) occur at the same time.

15. Critical Evaluation
 There is evidence from dual-task experiments that parallel processing is
possible. It is difficult to determine whether a particular task is processed in a
serial or parallel fashion as it probably depends
 (a) on the processes required to solve a task, and
 (b) the amount of practice on a task.
 Parallel processing is probably more frequent when someone is highly
skilled; for example a skilled typist thinks several letters ahead, a novice
focuses on just 1 letter at a time.
 2. The analogy between human cognition and computer functioning
adopted by the information processing approach is limited.
 Computers can be regarded as information processing systems insofar as
they:
 (i) combine information presented with stored information to provide
solutions to a variety of problems, and
 (ii) most computers have a central processor of limited capacity and it is
usually assumed that capacity limitations affect the human attentional
system.

16. Critical Evaluation
 2. The analogy between ....system.
 BUT -
 (i) the human brain has the capacity for extensive parallel processing
and computers often rely on serial processing;
 (ii) humans are influenced in their cognitions by a number of conflicting
emotional and motivational factors.
 3. The evidence for the theories/models of attention which come under the
information processing approach is largely based on experiments under
controlled, scientific conditions.
 Most laboratory studies are artificial and could be said to lack ecological validity.
 In everyday life, cognitive processes are often linked to a goal (e.g. you pay
attention in class because you want to pass the examination), whereas in the
laboratory the experiments are carried out in isolation form other cognitive
and motivational factors. Although these laboratory experiments are easy to
interpret, the data may not be applicable to the real world outside the
laboratory. More recent ecologically valid approaches to cognition have been
proposed (e.g. the Perceptual Cycle, Neisser, 1976).

17. Critical Evaluation
 Attention has been studied largely in isolation from other cognitive
processes, although clearly it operates as an interdependent system with the
related cognitive processes of perception and memory.
 The more successful we become at examining part of the cognitive system in
isolation, the less our data are likely to tell us about cognition in everyday life.
 4. The Models proposed by Broadbent and Treisman are 'bottom-up' or
‘stimulus driven’ models of attention.
 Although it is agreed that stimulus driven information in cognition is
important, what the individual brings to the task in terms of
expectations/past experiences are also important.
 These influences are known as 'top-down' or 'conceptually-driven'
processes. For example, read the triangle below:
 Expectation (top-down processing) often over-rides information actually
available in the stimulus (bottom-up) which we are, supposedly, attending to.
How did you read the text in the triangle above?

19. Component of Model
• Sensory memory – input device
– What info is sent to the processor
• Short-term / Working memory
– Central processor, actively processes info
• Long-term memory / Knowledge
– Library of programs, algorithms, data, and
experiences that are stored for use
†Note similarities to computer!

20. Sternberg Paradigm
• Test of how info is processed
• Subjects (Ss) memorize list of digits
{4, 6, 5, 9, 3, 2}
• Given recognition test
9?
Yes/No
• Measure both accuracy and reaction time
(Msec.)
Some trials were false (8?)
Some were true (9?)

21. Think in terms of Memory
system!
9
6
5
9
3
2
4
LTMSTM / WM
-
-
+
-
-
-
Decision

22. Results
350
400
450
500
550
600
650
0 2 4 6 8
String size
Msec

23. Perceive
Stimulus
Generat
e
respons
e
Make
decision
9=9? 9=3?9=6? 9=2?
Perceive
Stimulus
Generat
e
respons
e
Make
decision
7=9? 7=3?7=6? 7=2?
6, 9, 3, 2
9?
7?
What would happen if the search string were 6 items?
What would happen if degraded the probe?
What would happen if we biased the decision process?

24.  Time to respond was linear function of size of
search string
 Each element added 38 msec to search time
 Serial position did not matter!
 Thus, search is exhaustive
 Sternberg’s conclusion: Ss engaged in serial
matching process

25. Goal of Cognitive Psychology: to
explain basic processes of
thought
Simple example:

26. Cognitive perspective
 Think about what had to happen in order for you
to answer that question.

27. “How many hands
did Aristotle have?”
Speech
Interpretation

28. Speech interpretation
 Segmentation--where are the breaks between
words?
 Where are the breaks between phonemes?
 Variability in phoneme production between
speakers

29. “How many hands
did Aristotle have?”
Speech
Interpretation
Interpretation of
question

30. Interpretation of question
 Word order dramatically changes sentences.
Compare “John wished he had jumped higher”
and “He wished John had jumped higher”
 Surrounding context also matters: Compare “He
smiled” and “He slowly took out the gun. He
smiled.”

31. “How many hands
did Aristotle have?”
Speech
Interpretation
Interpretation of
question
Find answer
in memory

32. Find answer in memory

33. “How many hands
did Aristotle have?”
Speech
Interpretation
Interpretation of
question
Find answer
in memory
Make decision:
answer or not?

34. Answer or not
How confident am I that I know the answer?
What happens if I don’t answer?
Is this a trick? (Psych. Classes are full of
tricks.)

35. “How many hands
did Aristotle have?”
Speech
Interpretation
Interpretation of
question
Find answer
in memory
Make decision:
answer or not?
Phrase the
answer

36. Phrase the answer
 *Two
 He had two hands
 I’m not sure, but I’m guessing two
 Two--what’s it to you?

37. “How many hands
did Aristotle have?”
Speech
Interpretation
Interpretation of
question
Find answer
in memory
Make decision:
answer or not?
Phrase the
answer
Create motor
commands to
lips, tongue, etc

38. Create motor commands
 Degrees of freedom problem
 Serial order problem

39. Summary: this shows basics of
cognitive perspective
 Emphasizes information and how it is transformed
 Think in terms of stages in which information is
transformed
 Stages communicate with one another, but one
stage doesn’t know what the other is doing.
 Like Computer Science there is Algorithm ,but
unlike Algorithm it varies from person to
person and the frame of mind an Individual is.

40. Critical Evaluation
 References
 Broadbent, D. (1958). Perception and Communication. London: Pergamon
Press.
 Deutsch, J. A., & Deutsch, D. (1963). Attention: Some Theoretical
Considerations. Psychological Review, 70, 80–90
 Neisser, U. (1967). Cognitive Psychology. New York: Appleton-Century-
Crofts.
 Treisman, A. (1964). Selective attention in man. British Medical Bulletin, 20,
12-16