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:
- Sensory memory
- working or short term memory
- long term memory
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.
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.