Capacity Limits of Information Processing in the Brain

By Marois, Rene | Phi Kappa Phi Forum, Spring 2005 | Go to article overview

Capacity Limits of Information Processing in the Brain


Marois, Rene, Phi Kappa Phi Forum


The human brain is heralded for its staggering complexity and processing capacity. Its hundred-billion neurons and several-hundred-trillion synaptic connections can process and exchange large amounts of information over a distributed network of brain tissue in a matter of milliseconds. Such massive parallel-processing capacity permits our brains to analyze complex images in one-tenth of a second, allowing us to visually experience the richness of the world. Likewise, the storage capacity of the human brain is nearly infinite. During our lifetime, our brain will have amassed [10.sup.9] to [10.sup.20] bits of information, which is more than fifty-thousand times the amount of text contained in the U.S. Library of Congress, or more than five times the amount of the total printed material in the world!

[ILLUSTRATION OMITTED]

Yet, for all our neuro-computational sophistication and processing power, we can barely attend to or hold in mind more than a few objects, and we can hardly perform more than one task at a time. We are routinely reminded of these severe shortcomings, for instance when attempting to read a complex passage while keeping an eye on some television program or when talking on the cell phone while driving. These anecdotal evidences have been rigorously documented in the laboratory; maintaining a cell phone conversation impairs simulated driving performance and can lead to 90 percent of observers failing to detect an unsuspected salient visual stimulus! The costs to society of our capacity limits in processing information are likely to be immense. For instance, driver inattention and other human errors have been estimated to account for nearly 40 percent of motor-vehicle accidents. How does such a sophisticated, multipurpose processing machine as the human brain exhibit such severe and, quite frankly, humbling limitations?

A rich history of scientific research has highlighted three major roadblocks during the flow of information from sensation to action. The first limitation concerns the time that it takes to consciously identify an object. We may have the impression that identification is instantaneous, but in fact this process can take more than half a second before our brain is free to identify a second object. A second, severely limited capacity is the number of objects that can be simultaneously maintained in short-term memory, estimated to be about four objects. It does not matter if more objects are shown to you; you will be able to remember or monitor only four of them. Finally, a third bottleneck arises when one must choose the proper course of action for an object or event. Suppose that while driving you see a road sign indicating your highway exit. While you are busy taking the proper action (for example, shifting lanes), you may be impaired at making other responses (such as answering a question from a passenger in your car).

WHY DO WE EXHIBIT SUCH SEVERE LIMITS IN CAPACITY?

Why does the sophisticated, multipurpose processing machine that is the human brain exhibit such severe limitations at multitasking? We can only speculate. The limited capacity of short-term memory is particularly puzzling, given that we can easily build computers that can rapidly store thousands of items. One possibility is that our brain did not need to be built to maintain a detailed representation of the visual world in our mind's eye because this detailed representation is just one look away. All we need to do is to open our eyes, and our visual system presents us with a detailed view of the world. It is also unlikely that during the evolution of the primate brain there was any strong pressure for our nervous system to fully identify visual objects or events in very rapid succession. Even under fight-or-flight situations, probably only one predator or rival needs to be identified at a time.

Similarly, it is unlikely that our ancestors had to make several split-second decisions at once. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Capacity Limits of Information Processing in the Brain
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.