Cognitive Architecture

The nature of memory

Memories can be categorised based upon a range of criteria. One method is to distinguish between "episodic memory" and "semantic memory".

Episodic Memory

Episodic memories capture "episodes" of one's life events and hold a chronological nature to their form. These may include memories of what was had for breakfast yesterday, or what happened at a family gathering for a birthday dinner ten years ago.

Episodic memories capture significant event memories of a first day at school, a first date, the birth of a child, activities while on holidays and many other activities that we, as humans, experience and remember throughout our life time.

Episodic memories are generally not involved in the formation of meaningful instructional or formal educational memories, but deal with personal first hand perspectives that help us recall our life's experiences.

Semantic Memory

Semantic memories, on the other hand, deal with the conceptual meanings of various memories that we learn and apply throughout the execution of our lives. Reading, writing, arithmetic, essay writing, computer programming and performing surgery are all primarily based upon acquiring and applying semantic memories.

Semantic memories enable us to identify meaningful information and to interpret and apply it in a range of tasks. 

Effect of Semantic Memory

Semantic memories interact with presented stimuli. For example, look at each of the following, and note what you "see".

In the first example most people read 'THE CAT', even though the centre symbol in each word is the same. The context of reading provides information which we use to help interpret the symbols.

In the second example most people will read each symbol as an example of the letter "a", even though no two symbols are identical. We can read an infinite range of symbols as the letter "a", even most peoples' hand writing, although we have never seen their handwriting before. We are able to do so because of our knowledge of what constitutes the letter "a".

Similarly, we are also able to recognise literally millions of different trees, as trees, even though no two are identical.

These examples demonstrate that we cannot help but to identify and to impose meaning on things that we sense. Humans are able to behave and think in 'intelligent' ways because of their ability to quickly identify meaning in presented stimuli.

Our knowledge and skills in activities as diverse as reading, driving, mathematics and gardening all derive from the knowledge base which we hold more-or-less permanently in long-term memory.

The next pages give information about each of the following as they relate to cognitive architecture:

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