Does telling someone to pay attention actually change how much they remember? You divide participants into two groups. One group is told to remember as many details as possible while watching a TV show. The other group is simply told to watch. Afterward, both groups answer questions about what they saw. Comparing the scores shows whether intentional focus improves how much your brain holds onto in the short time after viewing.

Your brain can hold a small amount of information for a short time — but does how you take that information in change how much you keep? You show 40 participants two sets of 50 flash cards. In the first round, they view each card silently for five seconds. In the second round, they read each card aloud. After each set, participants get five minutes to write down everything they recall. Comparing the number of correct items between silent viewing and reading aloud reveals whether active participation improves recall.

Feeling nervous can do more damage to memory than most people expect. You show twenty boys and twenty girls a set of twenty-five objects for two minutes. In the calm round, they write down every object they can recall. In the anxious round, each person is told just before reciting that they are being graded and watched by an assessor. Under calm conditions, both groups remember about seventeen to eighteen objects on average. Under that sudden stressful situation, the number drops to fewer than seven — a cut of more than half.

Not everyone holds the same amount of information in short-term memory. To test whether that varies by sex, you gather 20 male and 20 female participants aged 18 to 30. Twenty-five everyday objects are placed behind a curtain at the front of the room. When the curtain opens, participants have two minutes to study the objects. They then write down every item they can remember in five minutes. Comparing the average recall percentage across the two groups reveals whether one group consistently holds more than the other.

Memory capacity changes as the brain matures, but by how much? You show 20 flash cards to four groups: 10-year-old boys, 10-year-old girls, men aged 30 to 40, and women aged 30 to 40. Each person views the cards for 10 seconds each, then writes down everything they remember. When you count correct answers and compare averages across the four groups, the adults score slightly higher on recall than the younger participants.