Storage I: How Memory Works (Part 6 of 14)

And this brings us to storage...  to memory.  What is memory and how does it work?

Here is the current thinking:

Memory is not the placement of something in the mind, like a book on a shelf, but instead it is the establishment of neural connections, of something like footpaths through the brain.  Thoughts and experiences build connections between the billions and billions of neurons in the brain, establishing new networks and patterns of connections.  These are what we understand to be thoughts and memories.

And here’s one way to picture this.  

Imagine a stretch of sand, like a gradually sloping desert.  But it rains on this desert, and when it rains, water from higher ground runs across the desert sand.  This movement of water is the act of thinking.  Water moves across the desert like signals moving through the brain, and memories are the tracks left in the sand, the channels and rivulets across the vast space.  Every new idea or experience is a new source of water somewhere--sometimes a small trickle, sometimes a great cascade--and each new thought runs across the desert to lower ground, spreading out and criss-crossing previous memories, or funneling into a channel.

This works in interesting ways as a metaphor.  

(The associative mind)

In the highly associative mind, above, water spreads out and leaves many, ranging tracks across the sand, and every new thought, springing from different locations, criss-crosses the trails left behind by others.  Thoughts and memories are connected, and opportunities for remixes, juxtaposition, and new understanding are many.  The desert takes on many, multi-varied patterns.

(The habituated mind)

In the highly habituated mind, deep channels run through the sand, and new ideas or experiences funnel into these channels.  Water that doesn’t reach these channels pools up or evaporates, never quite making it across the desert.  In this mind, most thoughts and experiences run quickly and surely to their destination, and new and surprising associations are fewer.  

This works nicely as a metaphor for how the mind works--intersecting webs of waterways in the desert are like the neural networks that make up our thought processes and memories in the cortex.  Now, imagine those vast and intricate pathways on the desert floor wrapping around into a three dimensional, brain-shaped space.  In this space, the passing of the water across the surface of the desert is like the passing of our thoughts through the brain.  They come and go, springing from a source, from stimulation.  The rivulets we see carved into the sand are like memories, neural routes that are established through the mind.  They wash or fade away without use, or they are made stronger by repeated prompting, and from that repetition we develop neural habits of thought.  If, after a long period of time, some rivulets or pathways have been worn away, then a new source of water might run across the empty space, filling in--or carving out--what has eroded.  

And there two key takeaways from this metaphor:

The first is that association strengthens memory.  The number of connections built in the brain influences the number of times memories (or paths over the sand) are revisited, which influences the duration of the memory.  Intersecting waterways suggest more water will pass over a particular place.  Associated thoughts work similarly.  When we associate information, we retain it longer, because we recall it--we retrieve it--more often.  (It’s important to note that the organization of the associations is really important.  More on this in two posts, when we get to retrieval.)

For this reason, connecting what we share in the classroom to current events, to personal memories, to other contextual information, or even to simple mnemonics all help strengthen memory.  How we encode information influences its durability and flexibility in our minds.

Similarly, intensity of encoding influences memory.  The strength of the original stimulation influences what is stored and for how long.  A strong gush of water will carve a deep crevasse in the sand, and it will take a long time to wear away.  If new information is attached to intense sound, sight, or feeling (such as the profound pleasure of intellectual discovery!), then the memory is encoded more richly, and lasts longer.  Recall the great pride in the first “A” from that really difficult teacher.  It was a moment of intense pleasure.  Similarly, remember the extremely loud noise that once startled you.  It was less pleasurable, but you still haven’t forgotten it. 

But what happens to that memory once it is forged?  How long does it last?  What affects it while it’s hibernating?  These we’ll explore next!

This is the sixth of fourteen posts in a series about the role of cognitive science in education.

Introduction:

• Cognitive Science: The Next Education Revolution (Part 1 of 14)
• A Cognitive Model for Educators: Attention, Encoding, Storage, Retrieval (Part 2 of 14)

The Science:

• Attention: the "Holy Grail" of Learning (Part 3 of 14)
• Encoding: How to Make Memories Stick (Part 4 of 14)
• (Interlude) Long Term Memory and Working Memory (Part 5 of 14)
• Storage I: How Memory Works - Redux (Part 6 of 14) 
• Storage II: Sleep and Memory (Part 7 of 14)
• Retrieval: Getting and Forgetting (Part 8 of 14)

Implications and Opportunities:

• Cognitive Design: Essential Questions for Educators (Part 9 of 14)
• Character and Success... and the Cognitive Model (Part 10 of 14)
• Towards a Unification of Pedagogies (Part 11 of 14)
• Why Old School and New School Aren't in Conflict (Part 12 of 14)
• Technology, The Brain, and Teaching (Part 13 of 14)

Conclusion:

• Manifesto: The Art and Science of Education (Part 14 of 14)

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Images from Wikimedia commons, and my camera.

Also: some of this content is updated from a previous post.