Caffeine helps you nail down memories—if used after the study session

The wonder drug smiles back at you.

Arapahoe Public Library

Lots of people who are extremely skeptical of herbal medicines rely on one every day. It changes their metabolism, increases their focus, and alters their bodies in a variety of ways. It's called caffeine, and in many ways it's a wonder drug. Now, researchers have added yet another item to the list of things caffeine can do: it helps consolidate memories.

The team behind this work, based at Johns Hopkins and University of California-Irvine, says that teasing apart the effects of caffeine is challenging. "The general consensus among past studies is that caffeine has little or no effect on long-term [memory] retention," they write. But those studies are complicated by the fact that the caffeine is usually administered with a sufficient lead time to make sure it's having an impact while people are doing their memorizations. In those circumstances, all the other effects of the drug—"increased arousal, vigilance, attention, and processing speed"—can also influence the degree to which memories are formed.

To avoid this issue, the researchers didn't administer the caffeine until after participants had performed an image memorization task. Twenty-four hours later, they tested their memories with a mixture of images: some were the ones from the day before, some were completely new, and some were similar to the previous ones—called lures, they were meant to tax a user's memory.