Every day brings new information that is absorbed and incorporated into the memory’s huge store. Fortunately, new material is not scattered randomly in memory but linked and organised to help us find things when we need them.
The main way the brain organises its score of memories is by linking related information together to form a ‘ knowledge network’. When you are trying to remember something, you may find yourself following these links from one memory to the next until you find the one you want. The more links a memory has to other memories, the more possible ways there are for you to get to it. Imagine travelling around a strange city without a map – you are more likely to end up in a square chat that has six different streets leading to it than to find yourself in a square with only one street leading to it.
Memory by association
Over time, impressions and information become entangled in the network by their association with other pieces of information and events. Memories that have similar connotations form links based on meaning, called semantic links. Take, for example, your knowledge about cows. All the various things you know about cows – what they look and sound like, that they produce milk and live on farms – are linked because they are related in meaning. Remembering one may lead you to remember the others. Also, your memory of what cows are will be linked to your memory of what sheep are, for example, because these have similar associations. Seman tic links act like a cross-referencing system: once you have found a useful piece of information, you can connect with any more that might also be relevant.
Memories that are formed at the same time as one another are linked by association. These associative links are fundamental to our understanding of the world and often allow us to make predictions based on previous experience. For example, we soon firm an associative link between seeing rain and getting wet. Less clear-cut but often powerfully evocative associations contribute to episodic memories. When you hear a piece of music and experience a powerful recollection of another time and place, it is because these memories have a strong associative link in your mind.
Making links
Most of the time, semantic and associative links work unconsciously: as soon as one concept is activated in memory, activation spreads automatically to other ideas related through meaning or experience. Experts are able to learn new facts in their chosen field with little effort because they have a rich web of existing knowledge and so can instantly form semantic links between a new fact and many other pieces of information. Similarly, anyone can improve the efficiency of their knowledge networks by making an effort to relate each new piece of information to something they know already. This helps to form links that otherwise might not have developed.
Mental prototypes
One of the ways we improve the efficiency of learning and recall is by categorising objects into groups. For example, we would say that elephants, badgers and antelopes all belong to the group ‘animals’. However, in the human mind, not all members of a group fit in equally well. US psychologist Eleanor Rosch has shown that in the group of things called ‘clothes’, people feel that shirts fit in better than shoes. Similarly, people see sparrows as a better example of birds than penguins and carrots as a better example of vegetables than radishes.
Rosch argues that this is because we tend to have a mental image or ‘prototype’ of the most typical example we know in each category. We then put other things into that group based on how similar they are to this image. This may explain why some people find it hard to think of dolphins as mammals. They are mammals biologically, but they look similar to the mental prototype of a fish.
Word Associations
When you hear words, they trigger their memory traces and also activate the traces of other words (or concepts) with which they are associated. You can test this idea out on your friends or family.
- Read out the following list of words at a rate of one word every two seconds. Tell people that they will later be asked to write down as many as they can remember. Bed, rest, awake, tired, dream, night, eat, wake, comfort, sound, slumber, snore, food.
- Wait five or ten minutes, then ask everyone to list all the words that they can remember. When you look at the lists, you will probably find the words sleep and warm included in some. This happens because many of the original words are associated with sleep and warmth, and so the memory traces for these two words receive some activation, too. When people try to recall the list, one or both of these also come to mind.
