October 17, 2006

This Is Your Brain

As promised, I'm going to summarize Why Minimal Guidance During Instruction Does Not Work: An Analysis of the Failure of Constructivist, Discovery, Problem-Based, Experiential, and Inquiry-Based Teaching. I'll pull in other sources of cognitive science and focus on how it all relates to education.

In order to do, I'll break it down into at least three parts: our brain, how we learn and store information, and, finally, why constructivism doesn't work.

In this first installment we'll discuss how the human memory process works.

Human memory has three areas:
  1. Sensory memory
  2. working or short term memory
  3. long term memory
For purposes of education, we are concerned with working memory and long term memory. Sensory memory is basically just a temporary buffer for receiving sensory stimulus. Here's a pretty picture to get us started.

Long Term Memory (LTM)

Your long term memory is the relatively permanent memory store in which you hold information even when you are no longer attending to it. For computer geeks, think of LTM as your computer hard drive--a virtually unlimited hard drive that is central to all our cognitive processes. Information stored in LTM can be stored up to a life time in duration depending on how well the information is learned.

This brings us to an important point: The object of instruction is to alter LTM. If nothing has been altered in LTM, then nothing has been learned.

Experts are skillful in an area (domain) because their LTM contains a huge knowledge base of information concerning the area (domain). This knowledge base permits experts to quickly recognize the characteristics of a given situation and serves as a basis for them to determine what to do and when to do it. For example, expert problem solvers derive their skill by drawing on the extensive experience stored in their LTM and then quickly selecting and applying the best procedures for solving problems.

LTM is the central dominant structure of human cognition. Everything we see, hear, and think about is critically dependent and influenced by our LTM.

A common idea is that everything we have ever experienced is stored in LTM, but this is unlikely to be so. Much of what we experience is never attended to, or not attended to beyond a few brief moments, and probably does not result in activation of the LTM storage process.

This brings us to our next important area of memory.

Working Memory (WM)

Working memory is the area or space where cognitive processing occurs. We are only conscious of the information currently being processed in WM and we are oblivious to all the information stored in LTM. WM is the part of your mind where thought happens. Think of WM as your computer's RAM.

When processing new information, information not stored in LTM, WM is extremely limited in both capacity and duration.

Almost all information stored in WM and not practiced (or rehearsed) is lost within 18-30 seconds.

The capacity of WM is likewise limited to only a very small number of elements (or "chunks") of information. On average, the capacity of WM is limited to 7 plus or minus 2 chunks of information.

For example:

The string of random characters "eah ct tn ihe ttha" might represent 14 chunks of information and is probably beyond the capacity of the average person to retain in working memory without first memorizing it (placing it in LTM).

The string of random words comprising those characters "cat hat the the in" might represent 5 chunks of information to the average English speaking person and could most likely be retained in working memory, though we are starting to approach full capacity.

However, rearranging the same words into "the cat in the hat" might represent a single chunk of information to a person familiar with the Dr. Seuss canon. Such a person might be able to retain seven Seuss titles in WM greatly increasing his ability to process information over the previous two persons.

The limitations on WM only apply to new information that hasn't been stored in LTM. Information can be brought back and forth between LTM to WM as needed, so the time limits of WM become irrelevant. Another way of saying this is that information or processes that are automatic (well learned information stored in LTM) take up very little space in WM.

Information that enters WM fades away, or decays as soon as it is no longer attended to. (The duration of 18-30 seconds assumes that the information is not being actively rehearsed.) Information that is being actively attended to is represented by a pattern of neural activity in the brain. With sufficient rehearsal or practice, the information may eventually become stored in LTM. But information that is not more permanently stored is simply lost shortly after attention is directed elsewhere.

Because WM presents severe limits on the amount of information that can be held in mind simultaneously and on the duration for which it lasts once attention is withdrawn from it, WM is often described as the bottleneck of the human information processing system.

That's all we need to know about our brain for purposes of understanding education. In my next installment we'll discuss how we get information into LTM, how information is stored in LTM, the stages of knowledge, and burdens placed on WM when engaging in problem solving activities. Then, we'll be able to discuss why constructivism and other forms of discovery learning not only ignore how the brain works and how we learn, but completely goes against our knowledge of the brain and how it works.

Go to Part II


Anonymous said...


As someone who is mostly ignorant on this topic, your explanation has been illuminating. The picture is very helpful.
Also, my DD has APD and this helps me in understanding her condition.

Looking forward to more.

Instructivist said...

I always suspected that memory has something to do with learning. If you listen to the army of ed charlatans that dominate education you come away believing that using one's memory is some of the worst things one can do.

Anonymous said...

I like to make a distinction between top-down constructivism versus bottom up. Top-down (real world, thematic, etc. used by most schools) requires students to construct basic understanding and knowledge with little or no prior information. It seems that modern educators believe that knowledge directly taught to students is rote and not learned as well as if the student discovers it him or herlelf. Of course, they fail to define exactly what this discovery mechanism is, and most implementations are done in child-centered groups, thereby making it unlikely that more than a few ever obtain the unknown benefits of discovery. This is extremely wasteful of time and is neither necessary or sufficient.

Constructivism sounds good, however, and there are examples where students construct new understandings by individually applying prior knowledge and skills to new problems. This is what I call bottom-up constructivism - or, rather, homework for individual students; experience, for adults.

Anonymous said...

I agree with Steve H. Discovery learning can be effected by the methods eschewed by those who hold disdain for exercises, drills, homework or the like. Also as Steve points out, discovery can occur while information is being imparted directly.

Anonymous said...

"If you listen to the army of ed charlatans that dominate education you come away believing that using one's memory is some of the worst things one can do."

Yes, superficial knowledge. Learning requires hard work that is not often fun. As I have mentioned elsewhere, hard work is a filter and they don't like filters. They want to have kids learn basic (mere?) facts and skills in context; thematically or top-down. They think this makes the task easier. This sounds nice, but they don't get the job done. Those hard facts and skills are still hard in context. Then they convince themselves that it really isn't necessary.

You can easily see this in math. Lots of fun knowledge and learning different ways to add, subtract, multiply, and divide. But they don't bite the bullet and make sure that the kids master the basics. That takes hard work. Often, the argument revolves around doing lots of long division - the poster child for drill and kill versus understanding. However, their drill and kill philosophy extends to more important skills like manipulating fractions. As I have said before, they see little linkage between basic knowledge and skills and understanding.

My son has an amazing memory. I see daily the advantages he has on putting two (facts) and two (facts) together to create a higher level of understanding. This would never happen if he had to look up the information. He wouldn't even know what to look up.

KDeRosa said...

Re discovery, it definitely has its purposes. In fact, once students havve developed sufficient domain knowledge, discovery learning becomes increasingly more valuable. There is also the concpet of students learning more when they attend to the meaning of information, but I'll get to this in the next post.

Anonymous said...

"always suspected that memory has something to do with learning."

It does. From a connectionist standpoint, LTM is the ability to retrieve and reapply patterns. Learning is the recognition of a new pattern. For example:

"cat hat the the in"

requires that you recognize a new pattern, because it is a meaningless, ungrammatical string of words, while

"the cat in the hat"

causes previously learned patterns in the brain to fire, processing the sentence (those being patterns for the words, as well as the syntax and the semantics). Hence, nobody has to memorize "the cat in the hat."

Anonymous said...

It is interesting to see how memory research seems to have been almost completely ignored by education over the decades.

Maybe it just feels too much like that icky behaviorism stuff, I don't know.

When it does refer to memory, it draws on ideas that ignore WM (or STM)--the "salience" of an event correlates positively with it entering LTM; deep processing results in better learning, etc.

KDeRosa said...

There is credence to the notion that people remember things when they learn it with meaning or deep processing. This is the kernel of truth inherent in discovery learning. But, the flip side of the coin is what presents the problems -- discovering the wrong things will also be meaningful and more difficult to fix in memory, the deep processing burdens the mind by placing a cogntive load on it making information so discovered more difficult to remember, and there are opportunity time costs associated with discovery learning which generally results in less practice which and less transfer to LTM.

But I'm getting ahead of myself.

Anonymous said...

"There is also the concpet of students learning more when they attend to the meaning of information, but I'll get to this in the next post."

This, of course, is the idea behind thematic or real-world learning. One could argue that creating a knowledge framework is best done in context (thematically), rather than by rote, as in memorizing all of the presidents first and then filling in the blanks.

There are problems with both approaches. With a thematic approach, one may not have the basic knowledge or framework to make the learning stick. It also may not be systematic enough to provide a proper knowledge and skill framework. And rote learning may be lost without enough connective tissue, so to speak.

Also, the thematic approach does not work (as in math) if you have a lot of basic skills to learn.

My big complaint with grades K-8 is that they just don't want to dive in and get to work. They don't like hard work. They want learning to be fun and natural and to have kids become "lifelong learners" (ugh!). The result is play learning.

Unfortunately, I don't think a carefully developed presentation on how the brain works will get schools and teachers to set higher expectations.

Anonymous said...

This is why issues like ADHD can be so devastating to a kid. Short term memory is often shoddy with them.

My son has a horrible time with memory and recall. It affects every aspect of his life. Learning is so much slower and in some cases, life threatening (like not being able to remember dangerous situations.)

Instructivist said...

"I always suspected that memory has something to do with learning."

That was meant to be ironic and a dig at all those educationists who think it's horrible to commit knowledge to memory. Just think of all those pejorative terms educationists employ like "regurgitate".

Anonymous said...

"Maybe it just feels too much like that icky behaviorism stuff, I don't know."

Actually, there's a lot of truth in that statement. Connectionism isn't behaviorism, for a number of different reasons, but it certainly seems like it to those who don't understand it.

That was probably the strongest block to connectionism in my field, anyway.