As well as the episodic and semantic types of explicit memory featured in the first two parts of this series (and the implicit or procedural memory which seems to have no connection with consciousness), there is another important type of memory – working memory. How working memory actually works is far from a settled question. It may not be one thing – but several separate working memories. The working memory that I am discussing has these characteristics: it has limited capacity of 7 or less items in memory; it holds those items for a limited time, about a second unless replaced by new items; items being held can be manipulated; the items appear to be in consciousness or extremely easily brought to consciousness; they seem to be the focus of attention or extremely easily made so. This is the working memory that is needed for intelligence and correlates with IQ. It is needed for certain types of accurate detailed calculations and similar cognition. It is needed for creating and interpreting complex sentences. It is required for keeping concentration on a task and some other executive functions. Most descriptions of consciousness include working memory as well as a larger less detailed world view (a global ‘gist’) and attention. Avoiding problems with exactly how both consciousness and working memory are defined and bounded, whether one is a part of the other or they are separate mechanisms – let us just consider them as inseparable under normal conditions.
Daniel Kahneman introduced the terminology of System 1 thinking and System 2 thinking. System 1 is unconscious, automatic, very fast while System 2 is conscious, does orderly reasoning, and is very slow. I think that all actual cognition is like System 1, and System 2 only differs by passing through consciousness.
More and more it appears that cognition is primarily an unconscious activity. We are aware of only a very tiny proportion of the cognition our brains do. And even for that tiny proportion we are not aware of the actual cognition but only of the changes it makes in the items held in working memory. If I add 5 to 17, I am aware of: task is to add 5 to 17, add 5 to 7, that is 12, but it is 17 not 7 so add 10 to 12, answer 22. But I have no awareness of how these steps are done – my awareness just jumps from one step to the next. Even given that the cognition itself is not a function of consciousness – we still seem to require consciousness to feed and hold items in working memory so that they can be manipulated. Tasks that are not sequential are difficult to do using working memory and tasks that are sequential are difficult without working memory. When working memory is used, the changes in what is held in the working memory are registered in consciousness.
Working memory (and therefore consciousness) is involved in doing mental arithmetic because we need the explicit semantic memory to retrieve facts like ’5 plus 7 equals 12′ which we have been taught by rote as small children. The same is true of mental logic, games with rules like bridge or chess, where much of the reasoning is sequential and tends to need explicit memory.
Sentences can be understood or created in a way that seems effortless but it does require a certain amount of juggling – holding this word until it is clear which meaning I should understand by it or which ending is grammatical for it and so on. The words and idiomatic phrases are in semantic memory to be retrieved as needed. Much of the juggling is unconsciously done but the results are past through consciousness for all those cases where working memory is involved.
We need working memory to learn motor skills. Once learned they can be done without working memory or even consciousness. But when learning such motor skills sequence and timing are important and it seems that learning the rough motor idea of a sequence takes the sort of manipulation that can be done on items held in working memory. Once the rough motor program is there, it can be honed and smoothed without consciousness or working memory. Soon there is a high skill level that is disrupted by conscious thought. Golfers must not think about the mechanics of their swing consciously or they will lose their skill.
There is no reason to think of this use of working memory as ‘the conscious mind’. The word ‘mind’ implies a system of cognition; and ‘conscious mind’ implies a system of cognition that is separate from unconscious cognition. However, all the manipulation, all the cognition is not part of awareness. We are not aware of how it is done. We are not aware of how 5 is found a retrieved from memory. It just pops in. All we are aware of is the flow of events, the stream of consciousness. In is more reasonable to think of having one undivided mind which does the work of cognition and a small part of the results rise to consciousness and so we are aware of them – one pop at a time.
So again we come to the function of consciousness. It is involved in a particular type of thinking in that it holds the keys to working memory. This type of thinking is very important to language, mathematics and logic. This function alone would be worth its cost.