If you are reading this right now, I guarantee you have a great big brain. I mean really big and I mean based on the number of neurons you have. Your big brain contains about 100 billion neurons and you have about another billion hanging out in your spinal cord. The total number of connections between neurons-the important bit for processing-has been estimated at 100 trillion synapses.
Our big brains are superb at all sorts of activities (basically everything you do) including thinking. There's a good reason that Rene Descartes wrote "Je pense, donc je suis" (I think therefore I am). It's true. You do think because you are and you are what you are because you can think. But there's more to it. Or less, actually.
Having such really big brains sometimes tricks us into thinking we should be thinking about everything we do. This extends to the idea of controlling everything we do too. But control in a real micro-managing style. The potential downside of this is revealed when we think about things too much. Or even just try too hard.
One of my favorite examples for this is found in a scene in the 2003 Warner Brothers movie "The Last Samurai". Early on in the movie we see a samurai and an American soldier training together with wooden swords. The samurai is trying to train Tom Cruise's character Captain Nathen Algren how to use the Japanese long sword during combat. Captain Algren isn't doing all that well so the samurai switches to a discussion about how to think. He says that Algren "has too much mind".
How can you have too much mind? Can "mind" really even be quantified at all? At first blush this may does not appear to make much sense. But this is actually a very good description of mental detachment in combat. In Japanese martial arts this is called "mushin" or "mushin no shin" literally meaning "no mind" or "mind of no mind". The main implication is to focus on the task at hand-what really needs doing-by letting things happen naturally.
When you do a physical motor act a certain part of the cortex called the supplementary motor area is active. It's actually activated both in imagining and in doing real movements. Functional magnetic resonance imaging (fMRI) can reveal activity in the brain during skilled movement like golf. Golf represents an interesting combination of fine motor skill and gross muscular effort, similar to martial arts.
John Milton and colleagues at the University of Chicago conducted brain imaging while very high skill (members of the LPGA) and low skill (novice) golfers imagined pre-shot routine for a 100 yard approach shot. The supplementary motor cortex showed strong activity in the golf pros and in the novices. In a real golf swing this would also be the case for the motor cortex. Those are the parts of the brain that have to be activated in order to plan and perform the golf swing.
Very importantly, the novice golfers tended to show much more activity in many other parts of the brain. These included those parts of the brain more active during learning motor skills and "on-line" control (basal ganglia and cerebellum). The main point is that there was activity in more brain areas than those needed to just simply perform the golf shot itself. More resources in the brain are taken up by things that aren't strictly about making a golf swing in the novices.
Increased activity in different brain areas means a greater chance of error and interference. These additional areas can include the basal ganglia and cerebellum, areas that help interpret feedback and regulate and control movement, particularly during learning. The upshot (no pun intended) is that movement performance can actually be degraded. When it comes to brain activity, more is less (if you're a novice) and less is more (if you're a pro).
Another good example of how your conscious attention can affect automatic skilled movement is walking or running. You can do them pretty easily with very little obvious attention, even running down the stairs. Many automatic levels of control and regulation are happening in your spinal cord and your brain to do that for you. But if you try to think about it too much you can even mess up something as apparently "simple" as walking. If you ever try watching your feet very closely while walking quickly down a stairway you are almost guaranteed to trip yourself. You start to exert conscious control over things that are already well controlled and you mess it up.
Learning motor skills takes us from the practice mind all the way to the automatic performance mind. When they are in a "slump" we often hear comments about golfers, tennis players, and other skilled athletes that they are "thinking too much about" what they are doing. When hitters are in a slump in baseball "over-thinking things" is almost always invoked as an explanation of what has happened. Having "too much mind", in other words.
Of course, a lot of practice and training is needed to get to the mindset of "mushin no shin". Plays, movements and movement sequences need practice until they can be performed almost unconsciously and arise almost spontaneously. And it also means letting our brains and bodies do what we have trained to do. A lot happens automatically during movement.
I realize I run the risk here of appearing to suggest that we shouldn't be using our brains! Sounds like an absurd position for a neuroscientist to take, but it follows that we need to use our brains more effectively and more efficiently. And that often means letting different part so our nervous system do the jobs they need to do and which they are good at without us constantly trying to do them on purpose.
The bottom line is sometimes you need to use your brain less. A quote from Haruki Murakami's brilliant novel "1Q84" is useful here. A main character Aomame reflects and changes Descartes quote to "I move therefore I am". Letting it happen is a good way to put your thinking into action.