I have spent thirty five years teaching students during their 16-18 phase of education which is well characterised as their ‘exam years’. My job is clear: follow a syllabus, do my best to make it understandable, provide opportunities to apply new knowledge and through testing, revise and learn stuff in preparation for a final public exam. Memory recall is of course fundamental to their final performance.
It has been shown recently1 that short term memories (located in hippocampus) and long term memories (in cortex) are laid down at the same time in response to an event. There is a day or so lag in any access to the long term memory though it’s there. The researchers state that communication occurs between the two types of memory but their findings have moved away from the older idea that long term memory is created by input from the short term memory often by repetition … until so to speak it ‘sticks’.
This conventional model of ‘short creating long’ also asserted that powerful and meaningful events ‘stuck’ more readily than the trivial. In short, in a teaching context, it is noticeably harder for a young person studying computing to recall the features of ‘Big O’ theory than it is to remember any errors relating to, say, their first sexual encounter!
Our response as teachers, unable or unwilling to compete with the last sentence is to saturate their days with repetition of the deeply unmemorable … hoping for a ‘stick’. Sticky by repetition? I doesn’t really work for me. The new findings though beg the question as to why two copies are created at the same time. I think the answer must lay in a concept of ‘synchrony’.
If hypothetically, long term memory constantly ‘polls’ short term memory, looking for similarities and differences, then when comparing its latest image with the current or recent in short term memory, the act of comparison itself may give a pointer to a mechanism to explain much of how we remember.
So for example, given an everyday event such as an encounter with a pet over a period of time, there will be a lot of synchrony between the recent ‘updates’ to the long term memory and the current store of short term memory. There will of course be small differences due to the dynamic relationship between owner and pet, so using the categories ‘same and different’ there will be some things in the ‘different’ camp and much in the ‘same’ camp. The long term store could be using the equivalent of a computer’s journaled file system where the differences only are updated into a permanent sore and the similarities acknowledged but with no action taken.
Obviously, near perfect synchrony could be achieved when, say, encountering a vase in the house, maybe many times each day. This always will result ‘no action’ and enough ‘no-action’ will result in the ‘event’ being downgraded to ‘wallpaper’, that is, near cognitive invisibility. On the other hand, the sudden loss of a loved pet for example will result in the long term memory being unable to get any significant synchrony with the short term memory. It may register total absence as a kind of change that cannot easily be integrated as an update and duly inform the conscious brain. Items like the pet’s basket may now incidentally increase in visual-memory significance (in the absence of the pet) during the brain’s repeated attempts at ‘normal synchrony’. Such attempts if regarded as important ( to memory integrity) may be the source of the conditions recognised as distress, grief and so on.
A severely frightening event, say in combat environments, will be stored in both memories so removal from the situation could cause a similar absence of synchronous events in the short term memory as described above. Again, this lack of synchrony will cause an alert, only this time (as your very survival is at stake), the long-term memory will rapidly and repeatedly scavenge the short term memory for synchrony ‘hooks’. This may be much more significant than the empty pet basket, possibly resulting in inappropriate behaviour as non-synchronous events are labelled significant and in desperation, labelled falsely as candidates for synchrony. For example a car backfire could be mistaken for a gunshot as both the short and long term memories are updated and ‘synced’.
In my own case having suffered multiple bee stings resulting in anaphylaxis many years ago and having been removed from the likely possibility of this happening again reacted or rather over reacted to the sound of a ‘drone’ copter mistaking it for a bee swarm. I had no idea I was looking out for this sound, but part of me certainly was.
There is a lot to be said however for having two copies of an event, one quickly refreshed, the other permanently stored. It gives us the ability to recognise change. An animal that fails to spot that a stone has been moved overnight may miss the predator lurking behind it! ‘Same and Different’ is a very common and familiar ability for us. We soon ignore the wallpaper and we quickly spot changes in behaviour.
Back to the more prosaic world of teaching. As a teacher my job is to get students to understand and hopefully remember a body of knowledge. I worked using the principles of the old model; repeat, practise, test so what difference could the new model make?
Hmm...ok both long and short term memories are created at the same time.
Empirically ‘rememberability’ is proportional to the significance the student’s brain attributes to the ‘learning event’ … this is usually quite low probably because in a school day short-term memory updates ( ie lessons with facts) are so frequent that they have to be ever-changing-wallpaper in a sense and therefore ‘same’ not ‘different’... Hence the teacher’s endless search for novelty, impact, stimulation and so on in order to upgrade the events to a ‘stickier’ significance … this is conventionally regarded as good teaching.
If however they have had the lesson, no matter how quotidian, it’s already in short term, and it should be in the long term memory ( the Holy Grail of teaching) too. and so the only problem is accessing it! But how?
The answer must be to force the brain’s hand as it were by wiping out the short term memory on demand after a period of continuous revision. Maybe surgery is too drastic to copy from the originl experiements with mice but there is another way.
The easiest way to do this is with alcohol consumption. Many have suffered short term memory loss from over indulgence.
Research helpfully has shown that alcohol the night before does not affect academic performance in student2 exams, other work with more consumption ( seven pints of beer) even showed an improvement3.
I think we’re onto something her.
1) http://www.bbc.co.uk/news/health-39518580
3) https://www.theregister.co.uk/2010/03/24/drinking_and_exams_mix_well/shows an
