Strong emotion aids memory

New York Times : In humans, seemingly trivial memories, when associated with a strong emotional response, can be filed away and recalled much later. To study that phenomenon, Joseph Dunsmoor of New York University and coworkers conducted an experiment in which they showed participants a random series of photographs and asked them to categorize each image as either a tool or an animal. They were then shown another series of photos to categorize, but in this second round, half the participants received a mild shock when they saw tools, and half received the shock when they saw animals. In a series of tests to measure how well the participants remembered the photos, the results varied depending on when the test was given. Those who took it immediately remembered as many animal photos as they did tool photos. But those who took the test hours later remembered more items in the category for which they had received a shock.