In the classic film ‘Casablanca’, there is a famous scene when Humphrey Bogart instructs the piano player to “Play It Again, Sam”. But, despite its fame, it never happened. The film doesn't actually contain its most iconic quote. So if you do remember that line from the movie, your memory has made an error - you've forgotten what actually happened in the film, recollecting instead something that wasn’t there in the first place. But should we worry?

We tend to think of forgetting as if it's a bad thing, because we only notice it when we fail to recall something important, like someone’s name. In fact, remembering people's names is something that people are generally pretty bad at.  We also tend to worry about our memory errors, concerned that our memory might be getting worse. But forgetting may be more important than you think.

Imagine taking a walk down Princes Street. The amount of information your brain will handle will be huge. The shops, the people, the famous buildings, the trams and buses; all of these and more will be processed and, if necessary, responded to. Yet, once you've successfully avoided the oncoming tram, there is no need to remember anything about it. Much of the information we encounter every day, becomes quickly irrelevant to us and would be better forgotten.

On the other hand - as any student about to take an exam will tell you - there are some things that really do need to be remembered. Forgetting, paradoxically, might be a mechanism that helps us filter out unimportant details. What we experience as problematic forgetting might happen when this filtering process doesn't quite work properly.

This is slightly at odds with how we think about memory. We often assume that people can act almost like a video camera, that they can review an incident in their mind’s eye as if they were reliving the event exactly. In fact what happens is that the memory is reconstructed when it is recalled. Some information is correctly remembered while other material, is lost to forgetting. Subsequent attempts to remember the same material will then be affected by what was remembered on earlier attempts. In this way our memory can be subtly moulded over time by forgetting and recollection.

So what can we do to help ourselves remember important information better? I have three suggestions. Firstly, rest can help. Work done by Dr Michaela Dewar at Heriot Watt University has shown that periods of rest immediately after learning can help consolidate memories - a process that also occurs during sleep, so getting a good night’s sleep is good too.

Secondly, it is much easier to remember something that you understand. For example, experienced home bakers watching the Great British Bake Off will find it much easier to understand and remember information about how to avoid the curse of the soggy bottom than people who have never so much as raised a spatula in anger. This is important if you are facing a test or an exam in the near future, because it means that you're likely to remember more about the subject if you really work on trying to understand it rather than trying to remember as many facts and details as possible. Incidentally, this is one of the problems of partisan ‘fake news’ - which, despite being false, is very easy to remember as it is designed to fit in with its target audience’s political beliefs.

Finally, it can be helpful to attend to all the senses when observing things we’d like to remember, instead of focusing on purely verbal information like lists of names and dates. Doing this enables links to be drawn between information from different senses which can help memory. In our work in the Memory Research Group at Queen Margaret University we’ve consistently shown benefits when people are able to use location information alongside verbal information as they try and remember numbers.

So should we worry if we forget the odd thing here and there? Not unduly: forgetting is a part of daily life. Forgetting the odd fact, name or face is an extremely common part of the human experience and usually doesn’t signify any more than the fact that you are the proud owner of a human memory system and not a computerised one.

However, if you are having serious concerns about your memory beyond everyday lapses – or if you worry that you or someone else is beginning to experience obvious difficulties in memory that are getting worse, then have a chat with your doctor.

Stephen Darling

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