Human Journey

Distractibility May Be Caused By Excess Grey Matter

A model showing human brain-cell action is lighted by fiber optics; photo by John Schneeberger and Larry Kinney

Being called a brainiac may be a compliment but when it comes to gray matter, a person can have too much of a good thing.  Scientists at University College London recently conducted a study that links high levels of distractibility with an increased volume of grey matter in the brain’s left superior parietal lobe.

The reasons for this are not yet fully understood, but it might have something to do with the way the brain pares away excess neurons as it matures in order to more effectively carry out certain tasks.  The brains of adults who suffer from attention deficit disorder may have failed to complete this process, and the connection may also help explain why children tend to be more easily distracted.

The results of the study appear in this week’s issue of The Journal of Neuroscience.

For more of the latest science news, check out the National Geographic Library’s twice-weekly news rundown, Earth Current.

Alyson Foster works in the National Geographic Library where she purchases books for the Library’s collection and assists NG staff with finding research materials.
  • David Braun

    Too much of a good thing!

  • VideoPortal

    Quite why SPL size works this way is unclear, but Kanai speculates that it may be linked to that fact that as we mature, the brain s grey matter is pruned of neurons in order to work more efficiently.

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media