If you’re concerned about your brain, take tests.
…[N]ew research suggests that the very act of taking a test is enough to enhance long-term memory. Furthermore, testing helps students remember not only what they studied for the test, but also related, non-tested concepts.
The results “imply that as long as students retrieved a concept, other related concepts should also receive a boost,” the researchers write in the November issue of the Journal of Experimental Psychology: General.
from Live Science