Researchers at the University of Texas at Austin used neuroimaging to look at subjects’ brains while they purposely tried to forget something, finding that the subjects actually needed to focus more attention on forgetting, not less.

The researchers tracked activity patterns in specific areas of the brain while they showed images of scenes and faces to a group of healthy adults and instructed them to either remember or forget each image. They discovered that intentionally forgetting an image requires "moderate levels" of brain activity — more than remembering — and, interestingly, that scenes were easier to forget than faces, possibly because faces make more of an emotional connection.

Our memories change all the time — they’re regularly updated, modified, and reorganized in our brain during sleep. And we remember and forget information constantly.