Wednesday, 4 April 2007

How do we remember?

I did teaching and learning module for my MSC in pharmacy, to equip myself on the education aspect. That was in 2001. My MSc thesis was on the role of reflection in learning. So i read a lot of theories on how we learn. How the new information fits into our existing knowledge and how we understand our learning. I enjoyed it very much, and to be a good learner, you have to learn and know how you learn. With all these time spent on writing up my thesis, i gained a lot from it, not in terms of the score i get, but how it has enriched me ( yes, i anchor my target not on outcome quantified, ie scores, but how it enriched my life and learning).

Memory is another amazing arena. How do we remember something? What goes on in our brains? When i was in primary school, i once asked Lexin how she studied and managed to be an A student. I remember her telling me that she study and revise before she goes to bed. Western parents here have the habit of bedtime story telling to their kids when they were young. Now that i read all about memory and how our brain works, it all make sense now. I wish someone has told me all these theories years ago when i was a student.

There are nerve cells, or known as neurons, in our brains and they are connected in a complex network.A human brain has more than 100 billion nerve cells.The point of contact between cells is called synapse, and cells use chemicals to communicate with each others. Signals that travel through the neuron forest form the basis of memory, thoughts and feelings.

Short and long-term memories depend on the strength of the stimuli and the strengthening of the connections between cells.The increase strength of chemical signals is called Long-term Potentiation, LTP. Biologically, short-term memory is a temporary potentiation of neuron connections that can become long-term memory through the process of rehearsal and meaningful association.

· When the stimuli (like your senses, your thinking, your feelings,) is not strong and the connection between cells are weak, short-memory is formed. The region of brain which is active for short-term memory is called frontal lobe, the front part of the brain.

· According to this guy name Donald Hebb, Hebbian theory, any two cells or systems of cells that are repeatedly activated at the same time will tend to become associated. An interestingly, the cells become associated by tagging. That's how cells which are far way become associatede and communicate to generate the same response. A good analogy is internet and tagging.

· When the stimuli, signal is strong, the chemical signals will affect cell protein, new proteins and consequently new synapse pathways that reinforce the communicative strength between neurons will be formed which result in physical change of neuron.This permanent change will result in long-term memory.

The black squares are the activity, or firing in the brain cells before stimuli, tetanus in red. The green dots measures the activity straight after the stimuli. The grey dots are measured between 3-60 minutes after tetanus stimuli.

This graph shows with repeated stimuli, our brain cells achieve a new level of activity which last longer (showed by the grey dots on the right vs the black dots on the left). This new level becomes the baseline without the need of stimuli to achive this level. Meaning, once our short-term memory has sufficient repeated stimuli, it becomes our long-term memory where we don't have to struggle to remember it, it's just become part of our database.That's when you really know and remember something.

· Information will be transferred from short term memory to long-term memory via a region of the brain called hippocampus,named because its shape resembles the curved tail of a seahorse (hippocampus in Latin).The hippocampus is a bit like a sorting centre where these new sensations are compared with previously recorded ones. The hippocampus also creates associations among an object’s various properties.When we remember new facts by repeating them or by using other methods to improve our memory, we are actually passing them through the hippocampus several times. The hippocampus keeps strengthening the associations among these new elements until, after a while, it no longer needs to do so.

Alright, that's the basic concept. What really matters to us is how to improve our memory ? How to have long-term memoris that last for a lifetime.

Let's start from the very basic, something that my friend xin, has been using all these while: SLEEP

Sleep consolidate the memory traces stored in the brain over the course of the day.Thus, in both animals and humans, an increase in the amount of rapid-eye-movement (REM) sleep is observed during the night following a learning experience. Conversely, sleep deprivation adversely affects learning.

-> That explains my colleague who has been reading bedtime stories to her son since he was 3 months old have a son who is now 3, very good at words and vocabulary.

-> That explains people can remember things that they read at bedtime the next day.

The second method to improve memory is Organization which involve two main strategies: Repetition and Elaboration.

· When we talk about repetition, we relate to memorisation easily. Rote learning is a term that describe memorizing without understanding it, sounds familiar? This are those memorisation of history events to pass our exams.. "just for test".

· The alternative is Spacing effect that shows that we are likely to remember something when we rehearse it over an extended period of time. This is in contrast to cramming, which is obviously short-term memory. Spaced repetition emphasizes on active recall which increase the permanent retention of information

· Another tip to improve memory is the Zeigarnik effect which shows that we remember better that which is unfinished or incomplete.An example is we keep thinking about unsolved problem where we can't achieve a closure. So we keep on thinking and reflecting on it until we found the answer. That partly explain the regular breaks that we have in classes and when revising. Regular breaks is an application of spacing effect too.

· Association is another key to improve long term memory. In elaboration, we associate the new piece of information with other information that we have already recorded in your long term memory.In other words, we incorporate the new fact into a broader, coherent narrative with which we are already familiar.This will be the application part of our information. We haven't really learnt something untill we can make association and application to what we learn. In schools, teachers employ this by asking the students to have projects, or essays, or presentation. These output of learning confirms that the student understand the wider implication and have accomodate the new information into the existing framework knowledge, to be able to make-sense of their informtation input.

· Sounds familiar? We are likely to remember the painful essays and thesis, projects that we did, more than those cramming nights for exams.

To recap:
sleep, spaced repetition, association, and leave it unfinished and come back to it later. These elements help our memory. Of course, the most important of all, strees-free. Stress reduced our memory capability.


Reading this article it might possibly suggest you could try to do totally 3 repetitions, with 10 minutes in between, to let the information be stored more permanently. Of course this is then more some sort of rule of thumb, which might or might usually not work .
I read all the related article yesterday, and only write this article today. Last night, i have been reflecting over all these information and how to summarise it for you. Applying Zeigarnik effect .

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