P335 Cognitive Psychology, Prof. Kruschke

Representation and Process: Some Examples.

We infer what happens inside the mind by observing the stimuli that go in and the responses that come out:

Stimulus -->
?
--> Response
When we explain what is happening inside the mind with a theory, the theory must specify what information is being used and how it is being used. The specification of the content of the information, and its format, is called the representation assumed by the theory. The specification of how the information is used is called the process assumed by the theory. The explanation does not necessarily claim that the representation and process are really in the mind; instead, the explanation claims that whatever the mind is doing, a good description of it is in terms of this representation and process.

Below are two examples of everyday activities for which the representations and processes are (at least partially) outside the head. Because they are external, we can get a better sense of just what is meant by these terms, "representation" and "process."

Example 1: Explain how you look up a phone number.

Stimulus:
The desired person's name.		 -->
?
 --> Response:
His or her phone number.

Theory 1 Theory 2
Representation Content: Names and numbers.
Format: Alphabetically ordered list. 		Content: Names and numbers.
Format: List in order of frequency of use.
Process Move through list alphabetically until name is found, then retrieve corresponding number. Start looking at the beginning of the list, check each name as you go.

The physical implementation of the information is irrelevant to the explanation; the phone "book" could be bound paper, clay tablets, CD-ROM, or anything else.

You probably have several phone numbers memorized. Do you believe that either of these theories is a good description of how your mind remembers phone numbers?

Example 2: Explain how you add two numbers

Stimulus:
Two numbers.		 -->
?
 --> Response:
Their sum.

Theory 1 Theory 2
Representation Roman numerals.
Content: Symbols such as M, D, C, L, X, V, I.
Format: Usually larger to smaller, with inversions as shorthand (e.g., LIX is shorthand for LVIIII). 		Binary (base 2).
Content: Just two symbols: 0 and 1.
Format: Place system: separate columns for 23, 22, 21, 20, etc., from larger to smaller.
Process Lots of memorization of many miscellaneous combinations. Memorize just four facts (0+0=0, 0+1=1, 1+0=1, 1+1=0 carry 1); use place system with carries.
Example IX + V = XIV
1001
+  101
1110

The physical implementation of the information is irrelevant to the explanation; the symbol manipulations could be done on clay tablets, on papyrus, or in silicon chips.

When you add numbers "in your head" do you think that either of these theories is a good description of what your mind is doing?

Copyright © 1999 John K. Kruschke