On the other hand the psychological roots of his work have been revealed, and are now much more accessible (with study) than they were a century ago.

For some fathers, the motivation to be involved with their children has powerful psychological roots.

The psychological root of the problem is usually unidentified; therefore causing the treatment to be even more difficult.

There is no psychological or physiological root for his condition.

About the only mystery left is the psychological roots of the president's compulsion to lie under oath.

Media framing research has both sociological and psychological roots.

"People are always looking for the psychological roots; this happens all the time with my films," he said.

It was thought that the only way to get rid of the symptoms was to understand the psychological roots of the behavior.

Now, both were happening at once - and feeding off the same psychological roots.

In that way one might get some clues that would lead to its psychological roots.