There is no such ‘thing’ as the past. We live and experience our life in an eternally unfolding now.
However, we do have the ability to store and remember this unfolding present in our brain, nervous system and body. The common name for this stored experience of the present is memory.
Memories are not the same as data stored on your computer’s disk. This is a perfect copy, which can be retrieved completely at a future date. Our memories are not faithful duplicates of the present, rather they are reconstructions in real time, based on stored sensory experience and associations. And these reconstructions vary in quality and accuracy, and they can change in quality over time.
As you’ve probably noticed in your daily life, there are many things which we forget straight away, or very soon after the event. This phenomena of how long memories last and what influences this storage process has been the subject of much research.
Some of that research suggests that there is a functional physical aspect to this. For instance, it is thought that the hippocampus and perhaps part of the temporal cortex areas of our brain are responsible for storing longer term memories.
There are also differences between memories we are conscious of, and those which never make it to the conscious level. Driving a car is a good example of this. When we first learnt to drive, we were very conscious when remembering how to change gears. But with experience, we can drive from home to work with very little conscious effort in ‘remembering’ how to change gears.
Other ways of classifying memory, is the difference between somatic, or ‘fact’ based memories, such as the height of mount Everest. And episodic memories, which are unique and personal to us, such as what you felt when you woke up this morning.
It is believed that episodic memory is an important tool in our ability to learn from our environment and adapt our behavour accordingly. The richer our environment and experiences means that our brain literally grows, in terms of the number of neurons in our brains, and in the number of brain cell connections.
What is also interesting about us, is that a given memory may be segmented and stored in different parts of our brain. Some parts of our brain stores the emotional content of a memory, whilst other parts store the motion aspects, and other parts store the visual content etc.
This phenomena of segmentation may go some way to explaining why our recalled memories are not simple duplicates of events, but are a patchwork of reconstructed impressions. And it may also explain why we sometimes need a ‘clue’ to get our recall working for some memories.
This aspect is often termed our associative memory, and this understanding features in some memory improvement techniques, where a specific part of a memory is used as a hook to bring back a whole string of information.
Spurious memories are also another fascinating feature of our brains. It is believed that different memories can share the same physical parts of the brain, and hence this may contribute to false associations and distored momories. On the more positive side, this may also contribute to creativity and lateral thinking.
For a fascinating book on this subject (and a whole lot more) try: