How much information can the brain hold? The answer seems to be an almost unlimited amount, thanks to the brain’s dynamic memory-filing system. So why are there time’) when do we feel as if we forget things because our brains are filled and cannot ‘take in’ anymore?
Think of some little incident that happened to you recently – accidentally bumping into someone in the street, perhaps. Now imagine trying to convey every tiny piece of information contained in the recollection: the road you were on, the traffic, and the people. The color and texture of the pavement, a dog barking, the slight pain in your shoulder, your own and the stranger’s voices apologizing simultaneously, the thoughts that went through your mind. You could fill pages just describing that one event, even though it lasted only for a few seconds.
Think of the thousands of similar snapshot recollections you could summon up right now and the millions more char night pop up if something reminded you of them. Then consider the myriad things you know, from where the Eiffel Tower is to what a polar bear looks like. Then think of all your abilities: how to make a cup of tea, turn on the TV, drive a car. Amazingly, all these billions of ‘bits ‘of knowledge are held in your memory. BuecruYat array of information can not be compared to any man-made database because it is not scored statically, like the image on film or words on a page. We do not replay information from memory; rather, we re-create it each time we use it. A recollection is not an object – like a picture on a wall – that can be revisited and will remain the same. A recollection is a process, producing a slightly different experience each time.
Neural connections
All our experiences are produced by neurons (nerve cells) firing in the brain in response to what we see, hear, touch, smell, taste, and feel. Experiences become memories because the neurons that produce d the experience form connections with one another. When these neurons are not firing, the memory is merely a potential tendency for them to fire together again in the future. When that happens, it creates a faint replay of the original experience, and a recall of memory occurs. It is a little like one of those huge illuminated advertising hoardings made up of thousands of different bulbs; different pictures are produced by turning on and off different patterns of bulbs. When one picture is showing, the others exist only as potential patterns – and parts of each picture may be used to create other images.
Each time an event is recalled, the neural firing pattern is slightly changed, and this new memory overwrites the previous one. In a sense, memories are ‘memories of memories rather than recollections of events, and the brain can produce an indefinite number of versions.
Memory ‘overload’
The vast number of possible connections between neurons means that there is no danger of the brain filling up with long-term memories. So, how do we account for the common experience that our memory is unable to cope with what we ask of it?
One factor that contributes to ‘ memory overload’ is that our brains do not evolve to deal with what we ask of them today. As recently as 30 years ago, people did not rush around the way we do now, fitting numerous appointments into each day, meeting deadlines, and making complicated holiday itineraries. Perhaps we should regard occasional memory failures as understandable lapses, given the times in which we live.
Re-creating experience
The scattered elements that make up memory are reconnected each time the memory is recalled.
