As you play the Challenge, you may notice that as soon as certain words enter your brain, they flow right out of it, like liquid passing through a sieve. You’ve promised yourself to remember unctuous forever, but ten questions later, you see unctuous and you’ve forgotten what it means. When this happens, do you, like many of us, wonder if there’s something wrong with your brain?

That’s likely not the case. New brain research suggests that forgetting is not a sign of weakness, but rather an active process that may even help you learn. Think housecleaning, but instead of working with soap and hot water, the brain gets the job done with a protein called RAC. And when the brain is confronted with new information — such as when you start to answer new questions in the Challenge — the levels of Rac in the brain are increased. 

But why would the brain want to forget? Wouldn’t it be better to remember everything you’ve ever read, heard, experienced, or seen? Not, it turns out, when you’re learning new words. In Vocabulary Development, Steven A. Stahl's pithy volume encapsulating a career in Vocabulary education research, Stahl analyzes the way the brain’s active forgetting actually helps absorb the meaning of a word you’re exposed to multiple times in context. (Absorbing words you're exposed to multiple times in context is how you learned more of the words you know; and FWIW, it's the process you're mimicing when you play the Challenge.)

Here’s how it works: The first time you see a word in context, you get clues to its meaning. Some of these clues are dead-on. Others are vague at best or even downright misleading. And since your brain has no way to tell the good from the bad, it files them all away. But see the word in context again, and the brain will take note of the clues that show up a second time. Repeat this exposure many times, and the overlapping information will be further reinforced, forming itself into a cohesive sense of the word’s meaning.

What does the brain do with the clues that don’t show up time after time? This is where the brain’s active process of forgetting comes in handy. Those misleading and unwanted clues fade away, making themselves scarce — if only unwanted houseguests would be so kind.

So next time you play the Challenge, celebrate your brain’s ability to forget. And when you forget something you meant to remember, relax, re-read the explanation of the word, and trust that your brain will absorb it in due time.