This excerpt is from Jewish Meditation: A Practical Guide by Aryeh Kaplan:
Anyone who has ever worked on a difficult problem… knows that at a certain point the mind seems to “lock on” to the problem. At that point, solving the problem becomes the most important thing in the world, and every fiber of one’s being is concentrated on finding a solution… I know that I can accomplish things when in a “locked-on” state that I cannot accomplish otherwise.
…I used the term “locking on” since this is the subjective feeling that one has in the kind of problem-solving that I am describing. When one is locked on to a problem, there is tremendous, almost sensual joy in solving it. It is possible to go without food and sleep, to dismiss all fatigue, until the problem is solved. Beyond this, it appears that one can call forth intellectual resources of which one is usually totally unaware.
Being locked on to a problem also brings a person into a state of consciousness different from his normal state. A much greater portion of the mind seems to be involved in solving the problem than in a normal state. It could therefore be considered a “problem-solving”state of consciousness.
… not simply… a sense of greater awareness or alertness; rather… thinking in an entirely different mode.
The difference between ordinary intelligence and genius may not be so much a matter of a person’s innate ability as his ability to “lock on” to the work at hand and get into a higher state of consciousness. Ordinary people consider works of genius beyond their reach, but this might not be true, since the creator himself may be surprised at what he produces when in a “locked-on” state of consciousness. The degree of creativity that one has, whether in art or problem solving, may be several orders of magnitude greater when one is in a “locked’-on” state than when one is in a normal state of consciousness. It may be that the secret of genius is the ability to lock on to problems or creative efforts on a much deeper level than most people ordinarily attain.
This locked-on state of consciousness appears to be associated with increased physical energy. The pulse is quicker, and one may perspire profusely. Sometimes, one even has the experience of trembling with creativity. It seems that while one is in such a state, the energy that one is utilizing is much greater than normal, and not only is the mind completely involved in the effort, but also the body.