Whoever said "what you don't know can't hurt you" needs to rethink the position. Knowing what you don't know keeps you from learning what you need to know or would benefit from if you did know it. Likewise, there is the foolish notion, "Ignorance is bliss." We teach these mindless ideas to our children and then wonder why so many don't like school.
Anyway, what I really want to explore here is the notion of thinking about thinking. Scholars call this metacognition. But, it really is a simple idea that we all experience every day to various degrees. Suppose you look up a phone number in the phone book. You have to quiz yourself to see if you remember it well enough to dial it. That is, you have to think about what you know and if you know enough to complete the task.
These things are often done consciously, and your conscious mind has to allocate enough effort and thinking resources to perform the task. In this particular case, we are talking about working memory. You test yourself to see if you still hold all the phone number digits in working memory long enough to dial them without error.
The principle applies more generally to other and more complex tasks. Basically, humans use memory awareness to determine if they have enough relevant knowledge before they act. Obviously, such awareness improves the appropriateness and quality of the act. This reminds me to tell you about my new book coming out on April 8, Mental Biology, in which I explore how the brain creates awareness and what consciousness is and what it does. In my view, consciousness does many things, but this ability to realize what you know and don't know provides the enormous advantage of helping you know if you know enough and decide what to do, when to do it, and how to do it. Notably, there are many scientists now arguing that consciousness does not do anything. Everything we do, they claim, is driven by genes and unconscious programming. To them, consciousness is just the brain's TV screen to show you some of what it is doing. These people will hate my book.
Metacognition even occurs in some higher animals, and there are some interesting animal experiments on metacognition. For example, one study showed that monkeys can track what they are holding in working memory. In the test, food was hidden in one of four opaque tubes. On half the trials monkeys watched the experimenter bait the tube, so that they had to know if they remembered which tube had the food. On the other half of trials, monkeys did not get to see where food was placed. After a short delay, the monkeys were given a chance to pick a tube to get a food reward, and on uninformed trials the monkeys peeked into the end of each tube to see which one had the food. That is, they knew they didn't know which tube was baited, so instead of guessing they looked into each tube before acting. When monkeys saw the baiting, they immediately went to the right tube without peeking. That is they knew where the food was and they knew that they knew.
The food was a reward, and as we all know positive reinforcement typically motivates us and drives behavior. We do things if there is some benefit to doing it. This leads me to consider another study that explored the role of human consciousness in evaluating rewards and their degree of attainability. It is no surprise that high value rewards improve mental performance, and this works whether you assess the value consciously or unconsciously (as in conditioned reflexes, for example). How motivating high rewards are depends on what we know about their attainability. If we know we don't know enough to earn the reward, we may not make the effort needed. If we think the reward is unattainable, we won't even try.
The study asked the question of whether this principle applies to unconscious processing. In other words, can unconscious mind integrate reward contingencies with attainability estimates? In the experiment, each trial included showing volunteers a picture of either a penny or a 50 cent coin which would serve as a reward if they performed a subsequent working memory task correctly. But sometimes subjects were informed before a trial that the reward would not be obtainable on that trial, even if they performed the memory recall correctly. In each trial the coin was shown either for 17 msecs, in which case its value could not be perceived consciously, or for 300 msecs, which was long enough to register consciously. So, across trials, the subjects had to integrate reward value with attainability and do so either under conscious or unconscious conditions.
Results showed that efficient memory recall resulted when the trial showed the reward long enough for conscious registration and when the high reward was attainable. And of course, performance was better for the 50 cent piece. Amazingly, even in the unconscious condition, high rewards improved performance even when they were designated in advance as unattainable. In other words, unconscious mind could not integrate reward value and attainability. Thus, it seems that consciousness uniquely controls the allocation of neural resources needed to integrate these two kinds of information. Oh, and by the way, don't experiments like this establish that consciousness really does something, that it is more than the mind's TV screen?
A third line of research has to do with psychotherapy. Here, the whole idea is to think about what you are thinking and feeling and substituting that with more mentally healthy thought. Being aware of memories is crucial to this process. Recalling bad memories causes a disturbing experience to fester, but also makes them accessible to revision. I have discussed in earlier columns some new approaches to treatment of PTSD based on the reconsolidation of memories that occurs when you recall a memory. The whole business about consolidation is explained in my recent book, Memory Power 101.
Here, I want to explore the value of being aware of the associations that are helpful and those that are not in terms of dealing such things as addictions, phobias, and even PTSD. For example, anybody in the throes of withdrawal from cigarette smoking knows how disturbing it can be to see or think about ashtrays or other reminders. A typical response is to try and inhibit the reminders of the former pleasure. But avoiding such reminders is often impractical.
In my book, Blame Game, I explore the importance of being more aware of what you are thinking and doing so that when change is needed you can reprogram your brain effectively. It is difficult to change bad habits or behavior because they derive from well-entrenched memory. The remedy is to replace this memory with a better new habit or behavior. And the way to do that is to make the substitute memory much stronger than one you want to replace. You can make such new memories stronger, the way you would any memory. This is basically the idea of substituting a bad memory with a good one, wherein the good one has been made especially robust. My memory book shows multiple ways to strengthen any memory, and this approach can be especially helpful to make a good substitute memory that will substitute and displace a bad memory. In general, the approach is to:
1. Think often about the substitute memory and use traditional memory enhancement techniques to strengthen it.
2. Rehearse the substitute memory in different situations and places.
3. Space rehearsal of the substitute memory out over time, both within a therapy session or new learning situation and self-test for recall of the substitute memory several separated times.
So, hopefully the general point is made. Knowing what you know and don't know is really important. Such self-knowledge is necessary to make you more competent—even to make yourself a better person. And remember, self-knowledge resides in memory. As with all memory, it can be strong or weak, true or false, recalled or forgotten, useful or harmful. You decide.
 Klemm, W. R. 2014. Mental biology. The new science of how brain and mind relate. Prometheus. In press.
Hampton, R. R. et al. 2004. Rhesus monkeys (Macaca mulatta) discriminate between knowing and not knowing and collect information as needed before acting. Animal Cognition. Doi: 10.1007/s10071-004-0215-1
 Zedelisu, C. M. et al. 2012. When unconscious rewards boost cognitive task performance inefficiently: the role of consciousness in integrating value and attainability information. Frontiers in Human Neuroscience. doi: 10.3389/fnhum.2012.00219
 Klemm, W. R. 2012. Memory Power 101. Skyhorse Publishing.
 Klemm, W. R. 2008. Blame Game. How To Win It. Benecton Press.