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Long term memory is a funny thing. Generally, we think that we have either a very good long term memory or our perception is that it’s more akin to collecting water with a sieve: nothing sticks.

For those who think that they belong to the first category: heed this word of caution that follows.

Science tells us that many people’s long term memory is lousy in terms of accurate recall. How so? Psychiatrist Offer carried out a fascinating investigation. He surveyed a bunch of fourteen year olds in 1962 and asked them a whole load of pretty personal questions involving home life, sexuality, religion, parental discipline and general activities. That in itself is not remarkable but this next point is. He not only kept the results of the survey but then re-surveyed the same people 34 years later in 1996. The purpose was to discover how robust the long term memories were.

The results were interesting. There were significant differences between the adult memories of what happened as an adolescent and what was reported as happened as an adolescent. Accurate long term memory recall was generally no better than chance.

What’s going on that would cause such poor memory recall? The act of learning something is called consolidation. This means that the memory makes its way to long term memory. However, in recalling the memory, the brain must then reconsolidate the memory. Yes, reconsolidate the memory. Many scientists believe that the act of recalling a long term memory converts it to short term (more accurately called working memory) and that this occurs every time the long term memory is retrieved. This means that the working memory must be reconsolidated every time it’s recalled to change it back in to long term memory.

If that wasn’t bad enough, there’s another, even greater problem. In recalling the memory other memories bleed into it, as the brain actively engages in pattern matching the recalled memory with any other memories it thinks are associated with it an any way. The problem is: they may not be. The result? Long term memory is very suspect to influence.

The authors of the study made the significant conclusion that even more care is required in obtaining accurate historical information that was medical or psychological. This point could be applied to law enforcement offers (who seek to make sure witness statements are taken at the earliest opportunity after the crime is committed) and anyone requiring historically accurate information.

By the way, if we extrapolate the point about memory bleed, then the only way to prevent previous long term memories having other memories bleed into them is to not recall the long term memories in the first place! Oh, that’s helpful: not!

You can read more about the study here.



Memories take years to consolidate. Yes, years. The hippocampus, so intricately involved in memory creation with the cortex, doesn’t allow the consolidation of memories in the cortex for years. No wonder it is often so difficult to remember things.

What can you do?

To stand the best chance of memories making it to long-term storage we need to repeat. Exposure to most memories stand little chance of long-term retention. Unless, that is, they are heavily encoded. Shocks, traumas and delightful experiences make it to long-term storage because the emotional attachment to the memory is so strong. One experience is often all it takes. In the case of painful experiences our desire is that we never experience it again. The memory, however, is deeply encoded in our minds. We can weaken its grip but it’s unlikely it will ever completely fade.

What about the every day experiences that we want to remember such as someone’s name, a thing to do or a learning concept or fact? How can we increase the chances of remembering? Repeat. It might be common sense to think repeating will help remember but it’s remarkable how infrequently we do repeat things we want to remember. Not only should we repeat to remember but we should keep repeating. John Medina, he of the brilliant Brain Rules book, suggests that a school day repeating learning every hour or so in the day for a managed amount of time would enhance information retention no end. The challenge becomes avoiding boredom but the brain would thank you for all that repetition. The brain really is pretty poor at remembering things that we want to remember. One exposure is rarely enough to remember anything.

To enhance memory retention further, encode the experience or fact that you want to remember with new emotions, feelings and any associations you like. Yes, that actually means that there will be more things to remember! As counter-intuitive as this sounds, this helps memory retention.

So, there you have it: the tricks with memory retention are:

  • Repeat – and repeat – and repeat – at regular intervals throughout the day.
  • Encode the memory with as much experience, feeling and association as you can.

Did I say that the trick with memory retention is to repeat to remember at regular intervals throughout the day?…