Humans seek two distinct psychological states. One originates in sensation; the other in a cognitive judgment. The attainment of either permits a brief bout of joy, followed by hours, days, weeks, or months during which one tries to re-experience the lovely moment. Although a small proportion spend many hours of each day trying to capture the pleasures that originate in sensation, a much larger number spend the same amount of time gathering evidence that permits the judgment that self has matched its features to an ideal.

source: Jerome Kagan, An Argument for Mind, 152 tags: Pleasure, Personal Growth