The secret ingredient to great learning and teaching: forgetting

It turns out that many of us have the wrong mental model for how we learn. We think we learn by what goes in the brain, but we actually learn by what comes out of it. This is THE big idea from those studying how we learn. A surprising implication of this research is that forgetting is a great friend of learning.
This is an exciting area of research, according to Peter Brown, of Make it Stick: The Science of Successful Learning, and others like the renowned Distinguished Research Professor in the UCLA Department of Psychology Rorbert Bjork (this recent talk by Dr. Bjork is awesome).
The Theory: It's What Comes Out, Not What Goes In
We don't learn by what goes into our brains, but by what comes out. In other words, it is the hard work of what they call "retrieval" that leads to true learning. Just receiving information doesn't equate to learning. Just reviewing information (like students "going over their notes" before an exam) also doesn't help. And just transmitting information (like faculty who prepare for an eloquent, erudite lecture) is misdirected.
Imagine your mind is a forest. You have information hidden in different parts of the landscape but you need ready access to it. Learning is the development of the paths to the information. Without these paths, the information just overcrowds the forest, then eventually withers from lack of use or attention or both.
Putting it Into Practice: The Practice of Forgetting...and Remembering
The general take-away is to perhaps half the time you take in new information and double the time you take to:
Forget: taking time away from the new information. You read an article with key insights you want to remember. Go for a walk, talk with a family member or co-worker, work on something else, take a break.
Recall: without notes, force yourself to remember everything you can about the information, then check your notes to fill in gaps. You might talk out loud or write something to help you recall and process the information. You can repeat this a number of times: forgetting and recalling, forgetting and recalling. Making it a well-worn path to the information.
"Elaboration": this is what researchers call the act of connecting new information to existing information. This is like making paths not just to the new information but between areas of information where catalysis takes place and new forms of knowledge arise. Push yourself to make all kinds of connections. How does this relate to my work projects? My industry? My core values? Relationships? A book I am reading? A movie I saw recently? The work of one my life heroes?
Application: using this new information (perhaps combined with existing) to do something concrete in your personal or professional life. As soon as possible, put it into practice. Make it quick, cheap and painless. Just do it as soon as possible.
For faculty: take time in every class to review old information before moving on, but in a somewhat random fashion. Bjork calls this "interleaving": bouncing between different areas of knowledge and skill. And ask students to connect this new information to things they already know, are learning in other classes, internships they have had, etc.
For example, I will start class by asking a question about something we learned in Week 2 and relate to what we are discussing now. I ask them to "pair share" their thoughts and then we discuss it as a whole group. When you do this at nearly every class, the course content gets woven together and starts to look more like real life.
For students: take time for forced recall of information. Don't get in the comfortable trap of just reading over notes, problem sets, etc. The best strategies are probably things you already know:
reading over your notes or parts of text then closing it. Try to forget by doing something else. Then recall everything you can by making notes on blank piece of paper. Do this several times.
quiz one another. Get with good, serious students and quiz each other. Be sure to bounce around and not always go in the same order or sequence through the information.
note cards are still a great way to study. Especially if you go through them and make two piles: a pile of concepts and terms you know and a pile you don't know. It turns out to be very important to know what you know and don't know.
So, again we think we learn by what goes in the brain, but we actually learn by what comes out of it. We can use this important insight to quicken our learning, improve our studying and make our teaching much more effective.