1. Psychologists at Northwestern University showed that each time you recall an event, your brain alters the memory by integrating new information—perhaps drawing on your current mood, activity or location, among other things.

2. The moment of recall can also impair a memory, according to work at Iowa State University. Study participants watched an episode of the television show 24, in which a terrorist used a needle during an attack. Some subjects were quizzed on the plot before they all listened to a recap that incorrectly said the weapon was a stun gun. Only the people who recalled a needle during the quiz had trouble remembering the weapon later.

3. Neuroscientists at the Massachusetts Institute of Technology implanted false memories in mice. The rodents first learned that one chamber was safe but that another was not—in it, they received an electric shock. When the mice later occupied the unsafe chamber, the scientists activated the memory of the safe room using an optical probe. The next day, when the rodents again entered the safe chamber, they froze in place—a sign of fear—even though they had never been shocked there.

4. A recent study at Emory University showed it might be possible to inherit memories from our parents and perhaps even our grandparents. Researchers trained mice to shudder in fear in response to a specific smell. The children and grandchildren of these mice displayed the same reaction to the odor, despite having never come across it before.

5. A jolt of caffeine, equivalent to about 12 ounces of coffee, made study subjects at Johns Hopkins University more likely to recall information they had just learned—but the effect may work only on people who do not drink caffeine regularly.