1. Outline Of Today’s Discussion
Information Processing Theory: Psychology
Biological Information Processing
The Computational Approach: Marr’s 3 Levels of Processing

2. Information Processing Theory:
Part 1
Information Processing Theory:
Psychology

3. Information Processing Theory: Psychology
Alan Turing
“invented” the digital computer
Artificial intelligence – The branch of computer science in which computer
programs simulate intelligent behavior. Examples from everyday life?
Potential Pop Quiz Question – Generate your own example of how computer
vision could have practical applications in everyday life?

4. Information Processing Theory: Psychology
Connectionist Neural Network Model
In the computer-network model above, what are the
biological counterparts to “units”, “connections”,
and “activation levels”?
How do connectionist models “learn”?

5. Information Processing Theory: Psychology
This is an example of an
information-processing psychology diagram….
Simple boxes are used to represent complex physiological
phenomena, and ‘mental events’ –all of which are
strung together in a flow-chart.
Note the serial nature of the flow, which is
contrary to parallel distributed processing models.
(parallel in time, distributed in space across the brain)

6. Information Processing Theory: Psychology
This is an example of an
information-processing psychology diagram….
Simple boxes are used to represent complex physiological
phenomena, and ‘mental events’ –all of which are
strung together in a flow-chart.
Why do behaviorists dislike the phrase “mental events”?

7. Information Processing Theory: Psychology
This is an example of an
information-processing psychology diagram….
This box corresponds to Broadbent’s (1958) notion of attention.
How would you define attention?

8. Biological Information Processing
Part 2
Biological Information Processing

9. Biological Information Processing
Single-cell recording arrangement:
Also known as electro-physiology
The neural impulse is
also called an
action potential.
(Often measured as
‘firing rate’ or
spikes per second.)
Rate Codes vs Time Codes
Is this basic research, or applied research?

10. Biological Information Processing
Diagram of visual receptive fields
Potential Pop Quiz Question:
Which major theory of vision would be
better supported by this diagram,
structuralism or gestaltis,?
Explain your answer.
(Hermann grid demo online)

11. Biological Information Processing
David
Hubel
Torsten
Weisel
How are they similar to the simple
mathematical functions (e.g., linear functions)
that we talked about the other day?
Nobel Laureates from 1981…
and they are almost psychologists! 

12. The Computational Approach: Marr’s 3 Levels of Processing
Part 3
The Computational Approach:
Marr’s 3 Levels of Processing

13. The computational Approach: Marr’s 3 levels
The computational level – specifies only which input (information)
is to mapped to which output (information).
At the computational level, there is no specification about HOW
the input is to be mapped to the output. Examples of your own?

14. The computational Approach: Marr’s 3 levels
The algorithmic level – specifies how a computation is to be executed.
In principle, a given computation could be executed many different ways.
Example: Many different computer programs can accomplish a given task.

15. The computational Approach: Marr’s 3 levels
The implementation level – specifies how the algorithm is carried out on
a physical device (a computer or a brain).