Components of our brain are described, for convenience, as being part of the conscious brain or part of the subconscious brain. In fact, the two are inseparable in the sense that they must function together in a coherent fashion or we have severe problems. It is the description of how dependent our conscious selves are on subconscious activities that is perhaps the most intriguing aspect of Churchland’s exposition.
Consider memory, a function that we assume is under our control; it is something we believe we can recover accurately as needed—unless we can’t recover it at all. The conscious brain has no long-term memory. Memory is a mostly unconscious function that is recorded subconsciously. We can express the need to burn some information indelibly into memory, but, in fact, we have little conscious control.
Memory and consciousness both evolved as survival mechanisms, not as a means to memorize poetry. In an evolutionary sense, memory is designed to deliver to our conscious brain the information it needs to survive. In the most general sense, memory is the storehouse where everything we have learned about how to respond to changes in our situation is contained.
If the occasion at hand consists of having just said something stupid and hurtful to a close friend, the friend’s response is first noted subconsciously and the emotions the subconscious deems appropriate are activated along with a physical response (blushing, tears…) and a suggested vocal response. We can override the vocal suggestion, but usually the subconscious is correct because we have consciously and subconsciously created the tendency to recall these responses and associated emotions from memory due to experiences endured over the course of a lifetime. We have consciously participated in the training of our subconscious.
As an evolutionary mechanism designed to promote survival, it is difficult to see how memory would become a mechanism for remembering in perfect detail things that have been experienced. Some scientists continue to profess such a belief and have gotten themselves into great trouble as a result. In fact, memory seems to be highly fungible. It can decay over time; it can be selective in the sense of only storing the aspects of an event that are consistent with previously held convictions (think politics); or it can be altered over time to become more consistent with some other constraint.
If memory is necessary to our survival then our subconscious must have an immediate and specific response to deliver when a dangerous situation arises. There is no time to ponder alternatives. In other words our brain hates uncertainty; it prefers to make everything fit into a consistent picture. If an observation is made that is inconsistent with a preconception, the brain is quite capable of discarding the experience as an outlier (think politics), but if the new information is sufficiently compelling, the brain will alter the preconception, or create a new category to deal with the situation experienced.
What is of interest is the lack of conscious control we have over the memory function. When we want to remember something, all we are really capable of doing is pausing and hoping that the information will suddenly pop up into our consciousness.
The actual long-term storage of memory is a mysterious process. It is believed to occur during sleep.
How "unimportance" is determined is unknown.
Sleep itself is also a mystery. It seems to almost as old as life itself, but all of its functions have yet to be determined.
If sleep is a mystery, then dreaming is a mystery within a mystery. Churchland does not attempt to explain dreaming, but she does enlighten us about our physical state while dreaming. Dreams can become quite real and could cause us to take action in response to them. This would be rather dangerous in an evolutionary sense. Our species would not have survived long if every time we had a dream we ended up falling out of our tree. Evolution provided us with a mechanism to impose a near state of paralysis on ourselves to protect us from harm during dreams.
Churchland tells us that speech, the words we utter, is largely a subconscious process.
What we say depends on what we know and knowledge is stored in the subconscious. The string of words it presents us to say depends on the experiences that have been accumulated over the long period of maturation. This notion is rather surprising until you examine your own experiences.
"You will have noticed that if you stop to consciously prepare precisely what you will say next, you become tongue-tied. Then you do not talk in a normal fashion at all."
Saying scripted words in a way that seems normal and natural is an acquired skill, not a natural one. That is why not all of us are cut out to be actors.
Laughter is also indicated as a subconsciously generated response.
"When John Cleese in a Fawlty Towers sketch becomes so annoyed with his stalled car that he rips a branch from a nearby tree and beats the car, the crowd erupts with laughter. Ask yourself (if you indeed did laugh): Did you consciously decide that this is funny? Almost certainly not. You will be laughing before you can begin to say what makes the scene funny. If you consciously decide to laugh, it is forced and not as enjoyable as spontaneous laughter. What provokes your spontaneous mirth is begun by your unconscious brain, which, incidentally, will be sensitive to whether in the given circumstances it would be rude or improper or dangerous to laugh."
We have all witnessed scenes in which animals perform ritualistic behaviors when encountering other animals of their species. These are useful in finding a mate or in determining or discouraging a threat from another. We might think that we have evolved beyond that stage, but Churchland reminds us that we have a bit of ritual still programmed within ourselves.
She provides this example of an encounter with someone we wish to be on good terms with:
People seem to feel more comfortable when they are being mimicked. Subconsciously we seem to realize that.
Churchland’s book has provided a rewarding and enlightening experience for this inexpert but curious reader.
Other articles posted based on Churchland’s writing are:
Free Will an Illusion? Patricia S. Churchland vs. Sam Harris and The Self as Brain: Efferent Copy, Voices, and Schizophrenia.
For those interested in the subject of human memory I recommend Memory: Fragments of a Modern History by Alison Winter.