The area in our brain where we store information from our senses, working or short term memory, has shifted over time.  "As the human frontal cortex evolved, the circuitry for spatial working memory appears to have been displaced to accommodate the emergence of newer areas that mediate cognitive abilities, such as abstract reasoning, complex problem solving and planning for the future."  (NIMH)     Humans are capable of transferring knowledge from short term memory, STM, associating it with prior knowledge, reevaluating the information and storing it into another area of the brain,  long term memory, LTM.  But, it is interesting to me that while our brain has evolved to include areas for abstract reasoning and complex problem solving, the short term area is still so limited.  Humans can only store "7 plus or minus 2" bits of information into their STM (Abrams).  I tried an online short term memory test and found that I could easily remember 4, 5 and even six bits of information at one time, but my memory failed me when they displayed 8 or 9 items.  We've learned to live with this deficiency by chunking bits of information together.("Brain Compatible Teaching conference-1999)  I've been disappointed by the limitations of my STM many times.  I've been in a phone booth with no means to keep track of a number except to repeat it over and over again in my head till I get it dialed.  Only, if interrupted, I lose the entire number and have to start the process all over again. Or, I'm at the grocery store and I know I need one more item but I can't remember what it is.  Another common problem I have is entering a room and forgetting why I was going there.  I generally have to retrace my steps and start again hoping it will return to me.   Information in STM is very short lived , up to 30 seconds, this is probably essential to the functioning of our brain, but it causes great difficulties when we are trying to do more than one thing at a time.

Another area where our brain comes up short, is the transference of information from STM to LTM.    I've been working with my son on his multiplication facts, we go over and over them in an attempt to make them part of his permanent memory.   This has been quite a struggle. He may know them while we are working on them but he still loses some of the information the next time we start again.  I've tried repeating someone's name over and over while I'm talking to them in order to help me remember their name.  Unfortunately, if I don't see them for weeks, I usually forget their name anyway, "use it or lose it".  I should be able to place something into my LTM just by willing to do so.  Unfortunately it is much more complicated than that.  When I first studied STM and LTM it was thought that simply the rehearsal of information in STM would place it into LTM.  This may or may not be the only way,  "...it may be that something very similar to the initial learning event happens again and again, a process Tsien calls synaptic reentry reinforcement, or SRR." (Science Daily)    This acquisition of newly gained knowledge and the relationship it has to prior knowledge may be key to our long term memories.  As teachers, we are told to relate stories to real life experiences, to make connections between subject matter, to reinforce one concept using another and to constantly build on prior knowledge. These learning strategies are consistent with the way our brain processes information.  Another trick I've learned is to make the content affect the students emotionally. ("Brain Compatible Teaching" conference) Reading aloud the book, "Pink and Say" triggers the students' emotions and they are much more likely to remember the content.  I also draw brightly colored symbols that represent main concepts and hang them in my room to review occasionally.  The visual connections help the students to remember the concepts.

I wouldn't be surprised if eventually our brains could accommodate more information in our STM.  If our society continues at the pace we experience today and our brains are required to synthesize through more and more information at once, our STM may expand to hold more information or perhaps it will one day be easier to transfer information to LTM.  Until then, we must use tricks like chunking information and relating what we'd like to remember to prior knowledge.
 

References:

Brain Compatible Teaching conference 1999

Websites:

Abrams, Robert, Ph.D. February 2, 1998 An application of learning theory to American Tango: short-term memory

Long Term Memory

Science Daily  Instant Replay: Study Finds Potential Mechanism For Building Long-Term Memory, Princeton University

Short Term Memory Test

National Institute of Mental Health (NIMH)