Paying attention

All in all, research on working memory and selective attention shows that the conscious decision making systems in the brain exercise crucial control over the parts of the brain that are receiving information from the senses. And since working memory can be a gatekeeper to long term memory, all learning improves when the brain is forced to become alert to the incoming data. In other words, if the brain does not notice something in the first place, it can’t recall it later. The reason the brain needs to be told to be alert to things more subtle than a bolt of lightning is that it was designed not to pay attention  to everything  on its own.