The Two System View of Cognition

The two system view of cognition provides a means of understanding both how we can process information so quickly and why cognition fails and is subject to error. There are many two systems views of cognition, all of which share the same basic ideas. Perhaps the most noteworthy two system view is that of Nobel Laureate Daniel Kahenman.1

System 1 is named Intuition. System 1 is very fast, employs parallel processing, and appears to be automatic and effortless. They are so fast that they are executed, for the most part, outside conscious awareness. Emotions and feelings are also part of System 1. Learning is associative and slow. For something to become a System 1 process requires much repetition and practice. Activities such as walking, driving, and conversation are primarily System 1 processes. They occur rapidly and with little apparent effort. We would not have survived if we could not do these types of processes rapidly. But this speed of processing is purchased at a cost, the possibility of errors, biases, and illusions.

System 2 is named Reasoning. It is controlled processing that is slow, serial, and effortful. It is also flexible. This is what we commonly think of as conscious thought. One of the roles of System 2 is to monitor System 1 for processing errors, but System 2 is slow and System 1 is fast, so errors to slip through.

Consider the following problem. A bat and a ball cost $1.10 total. The bat costs a dollar more than the ball. How much does the ball cost?

The mind tends to offer the answer $0.10 because the answer seems simple, just the parsing of the $1 from the $0.10 In fact, 50% of Princeton students and 56% of the students at the University of Michigan came up with this answer. But this answer is wrong. If the bat costs $1 more than the ball and the ball costs $0.10, then the bat would cost $1.10, which when added to the ball cost would reach $1.20. The correct answer is $0.05. That would mean that the bat costs $1.05, and the two added together would yield the desired $1.10.

So this simple example illustrates how System 1 processes can lead us astray and how System 2 processes can set us right. System 1 processes are essential. Were it not for their speed, we would never have survived as a species. But they are flawed. System 2 processes are needed not only to monitor System 1 processes, but they are also the processes that cause us to learn and advance. With System 1 processes only, we would have remained a primitive species.

The important point is to be aware of potential cognitive illusions, errors, and shortcomings, so we can identify and compensate for them.

1Kahneman, D. (2003). A Perspective On Judgment and Choice: Mapping Bounded Rationality. American Psychologist, 58, 697-720.



© Douglas Griffith and, 2009. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to [Douglas] and [] with appropriate and specific direction to the original content.


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