Any intense experience, if maintained for more than half an hour, can leave permanent changes in the neural circuits involving emotion and memory. If the experience is frightening, the memory can continue to traumatize the individual for year. Brain-scan studies find that it takes less than one second for a word or a phase to trigger an emotional reaction in your brain. Negative states stimulate intensive limbic activity, and this causes the hippocampus to embed it into long-term emotional memory. Pleasant experiences do not trigger as strong a reactions and therefore are harder to recall than unpleasant ones. The more you obsess on a specific feeling, the more real I will appear to be. Newberg and Waldman suggest it is important to be careful what you pray for, meditate on, or obsess about, because it may eventually become your personal truth.