Consciousness is Memory
My proposition is that memory and consciousness are one and the same. There can be no memory without consciousness – that is, we cannot remember events that occurred while we were unconscious, whether asleep, anaesthetized, or comatose. Nor can we remember events of which we were “unconscious”, even though we were awake and “conscious” at the time. Equally, in a normal state of unconsciousness, memory does not accrue. .
Memory and consciousness are simply alternative names for the same condition of mental activity. We (in general) allocate these two equivalent terms differently on the basis of the temporal character (present or past) and stimulatory source (exteroceptive or interoceptive) of the contents of consciousness – “consciousness” for present exteroceptively sourced events and “memory” for past interoceptively sourced events. This is not a rigorous categorization, as we shall see. .
That memory should be subsumed under the concept of consciousness is apparent in that one can be in a state of virtually complete perceptual deprivation and still be fully conscious. One’s mental activity does not cease under this condition – it persists as memory recycled into consciousness (working memory). There is present awareness, but exteroceptive perception is minimal. Similarly, one cannot be conscious, that is, awake to present stimuli, without laying down memory, however short-lived; one’s consciousness cannot be divorced from memory.
Although the investigation of consciousness has more or less halted at the starting post, considerable progress has been made, in the field of cognitive psychology since the 1960s, in delineating the characteristics and mechanisms of memory. What we have learned of the nature of memory can be legitimately applied to consciousness. Three phases have been identified in the laying down of memory. Initially, and most ephemeral, there is Sensory Memory (“echoic” and “iconic” for sight and sound, respectively) which records the multitude of stimuli impinging on us. A subset from this record is selected for further processing immediately, while sensory memory retains briefly the vestiges of unattended sensations. Their brief retention persistence is revealed if, for some reason, processing (now called “attention”) is switched back to their fast-fading traces. Sensory memory has an accessible life of only a few seconds (longer for echoic than iconic), and will disappear without trace unless subjected to the further processing which characterizes the second phase of mental record keeping which constitutes memory.
The brief imprint of sensory memory serves to give us continuity or stability of exteroceptive consciousness without the necessity of permanent storage of the vast mass of information with which we are constantly bombarded. Consciousness of the world around us is thus no other than sensory memory.
In the next stage of processing, a subset of the impinging exteroceptive stimuli in sensory memory begin their progress into Short Term Memory (STM, sometimes called working memory). The process of their selection and entry is called Attention in cognitive psychology. STM is essentially the memory we function on in our conscious lives. Like sensory memory, STM records exteroceptive proximal stimuli but it subjects the selected stimuli to a much “higher” level of processing, retrieving the more detailed information from them that is required for their full delineation, for current purposeful activity. (Under the more encompassing definition of working memory it has afurther function in recalling already stored memories, as we shall see.)
Storage in STM is thought to be electrical, for (like sensory memory) it is subject to permanent loss if its electrical substrate is prematurely interrupted. STM processing takes up to half an hour before it is completed. Evidence for this is, for example, the loss of memory that occurs for the half hour or so prior to a severe blow to the head. The lead up to the blow, and the blow itself cannot be recalled, as if the person had been unconscious at the time.
Permanent storage occurs in the thirdphase of memory formation, Long Term Memory (LTM) when the electrical storage of STM has been transformed into chemical storage in the brain. It is thought possible that all stimuli (information) that have completed their time in STM are permanently stored in LTM, even if we have lost the paths of access for resurrecting them in memory.
As we have seen, attention is the term given to the process of selecting some exteroceptive stimuli from the full contents of sensory memory for further processing in STM. What has been learned of its characteristics supports the proposition that consciousness and memory are essentially the same mental phenomenon. Its investigation has revealed the need for a selection from the full array of exteroceptive stimuli for admission into full consciousness due to the brain’s limited capacity for information processing, conceptualized as “central processing capacity”. It has been demonstrated that we can only remember later what we have processed in STM to the degree to which we have processed it, whether to a lower or a higher level in a “hierarchy of tests”, from the purely sensory to word recognition. STM and consciousness cannot be differentiated at this stage. A limited central processing capacity means that we can only be conscious above the level of sensory memory of a subset of all the potential information impinging on us at any one time.
“Attention” in cognitive psychology refers only to the processing of present exteroceptive stimuli in STM. To fully describe consciousness, it must also be recognised that what has been attended to in the past, that is, long-term memories are part of its contents – its interoceptive component. In its conscious form, LTM is the recycling into consciousness of past processed information, that is, of earlier STM contents. If the initial processing of exteroceptive stimuli is primary consciousness, we might call the return to consciousness of its products from LTM, secondary consciousness. But human consciousness consists also, in the recyclings of secondary consciousness, of the reconstruction of memories into new relationships in what we call thought, and still further in recycling (bringing to consciousness again) the product of these reconstructions for further elaboration.
Further, and most peculiarly human, consciousness as thought can reconstruct what has never been processed exteroceptively, but exists only as the memorial transcripts of language. Recycled memory, as consciousness, creates a new present out of its record of the past, and this can function almost alone, and/or in synchrony with the on-going memorial creation of the exteroceptive present. This we might call tertiary consciousness.
Work relating IQ and central capacity makes it a plausible hypothesis that the limited central processing capacity available to consciousness means that the greater the amount of capacity at any time devoted to the processing of new exteroceptive information (attention), the less is available for recycling stored interoceptive information (memory), and vice versa – hence the advantage of quiet (i.e. to eliminate exteroceptive stimuli as far as possible) or a familiar environment (familiar stimuli make less call on processing capacity) when engaged in deep thought or other creative production, which is the restructuring of already stored information (memory); and a parallel need to be free from the distractions of memory and other cognitive tasks when executing environmentally interactive tasks demanding close attention to (advanced processing of) exteroceptive stimuli (e.g. playing tennis, doing a jigsaw).
Whether we retain access to our long-term memories or not seems to depend on whether and how frequently we recycle them into consciousness. If neglected, they are moved into some hinterland of the brain, whence it may be that they can have unconscious (conditioned) but not conscious influence on our behaviour. The role of review in establishing long-term memories is demonstrated in the tactics of deliberate memorization, such as students used in preparation for exams in the past – dwelling on individual items of information and testing recall, or reading a text several times. Indeed, some degree of conscious review may be necessary to bring the STM process of transformation into LTM to completion.
Thus while a large part of our consciousness is forced on us by our current material environment, a large part also is constructed by ourselves from our stored memories of our past exteroceptive encounters – by our own peculiar, and to a large extent chosen, system of memories, developed over time from what, among the multitude of impressions the world provides, we have recycled sufficiently to maintain accessibly in LTM.
Most people over 50 are aware that as their memory file has grown larger, locating the required memory can become much less immediate than in youth when the file contents was smaller (just as with a paper file); and most will be familiar with the weird experience of trying to recall a name without success, only to have it suddenly arrive in consciousness several hours later, as if one had set an automatic search in motion which has finally come up with the answer when one’s thoughts were on quite another matter.
How we file our memories, how we “tag” them, for recycling into working memory consciousness, whether they actually fade chemically or merely lose their access routes over time, perhaps due to interference from memories laid down later in time, the greater performance ease of “recognition” over “recall” in reactivating stored information into consciousness, and so on. – these are all matters that have been investigated in the experimental science of cognitive processes, and probably belong to “memory” rather than the more general field of “consciousness”. No doubt, too, there are neurological answers to these questions as well as phenomenological ones, if neurologists care to take them on.
Against this, it is also clear that the brain plans and executes many essential survival (including metabolic) functions without the monitoring interposition of consciousness, such that there is also some other allocation of its processing capacity devoted to enabling the organism’s preservation of homeostasis and intactness in a constantly changing external environment.
A cockroach when running about has primary consciousness in the sense of processing of exteroceptive data, but we might have doubts as to its capacity for secondary consciousness, and we would be most reluctant to admit its capacity for tertiary consciousness, as above. The psychological concept of conditioning in animal learning attempts to explain the functioning of such creatures without invoking consciousness in the form we consider most essential to its human manifestation, namely its memory contents.
In summary and conclusion, my original proposition that consciousness is coterminous with memory should be elaborated to declare that consciousness is information processing plus memory in a continuous self-integrating loop of mental activity. The characteristics of “Attention”, and “Memory” already uncovered in cognitive psychology are the characteristics of consciousness also. This coalescence creates the need to distinguish in terminology between memory in its inactive (unconscious) and its active (conscious) modes. The terms consciousness and memory alone will not do, as we need to distinguish terminologically the exteroceptive and interoceptive contents of consciousness.
It is true that none of the information about the structure and functioning of memory related here is new, but I believe that putting it in the context of consciousness and positing its relevance for what we conceive of as consciousness is.
In implicit acknowledgement of the identity of memory and consciousness, the French use the word “rapelle!” – “recall” (remember) – as a road sign in dangerous spots, meaning, in fact, “concentrate” (attend, be conscious).
Nature from time to time publishes articles on consciousness which take neurological science as their starting point and in which the study of consciousness is conceived as a new departure in the field of the study of mind. It does not seem to be realized that consciousness has already been extensively studied phenomenologically under other names in the field of cognitive psychology. In neglecting these findings, neuroscientists deprive themselves of what might be useful points of departure and guidelines to direct their own investigatios.