As I say, I'm still working my way through this field.

The next article I'll read will be Willingham on The Death of Implicit Memory:

Abstract

The thesis of this article is that implicit memory does not exist. Implicit memory phenomena are distinct from explicit memory phenomena at a neural and information processing level, but there is such variety among the implicit memory phenomena that nothing holds them together in a common category. Other researchers have distinguished among different types of implicit memory, but have retained the superordinate category. Extant data is evaluated in light of how classification systems should be developed, and it is concluded that there is currently not a reason to retain the construct "implicit memory."

Here's Willingham in a passage from Malcolm Gladwell's article on The Art of Failure 'The Art of Failure':

"Choking" sounds like a vague and all-encompassing term, yet it describes a very specific kind of failure. For example, psychologists often use a primitive video game to test motor skills. They'll sit you in front of a computer with a screen that shows four boxes in a row, and a keyboard that has four corresponding buttons in a row. One at a time, x's start to appear in the boxes on the screen, and you are told that every time this happens you are to push the key corresponding to the box. According to Daniel Willingham, a psychologist at the University of Virginia, if you're told ahead of time about the pattern in which those x's will appear, your reaction time in hitting the right key will improve dramatically. You'll play the game very carefully for a few rounds, until you've learned the sequence, and then you'll get faster and faster. Willingham calls this "explicit learning." But suppose you're not told that the x's appear in a regular sequence, and even after playing the game for a while you're not aware that there is a pattern. You'll still get faster: you'll learn the sequence unconsciously. Willingham calls that "implicit learning"--learning that takes place outside of awareness. These two learning systems are quite separate, based in different parts of the brain. Willingham says that when you are first taught something--say, how to hit a backhand or an overhead forehand--you think it through in a very deliberate, mechanical manner. But as you get better the implicit system takes over: you start to hit a backhand fluidly, without thinking. The basal ganglia, where implicit learning partially resides, are concerned with force and timing, and when that system kicks in you begin to develop touch and accuracy, the ability to hit a drop shot or place a serve at a hundred miles per hour. "This is something that is going to happen gradually," Willingham says. "You hit several thousand forehands, after a while you may still be attending to it. But not very much. In the end, you don't really notice what your hand is doing at all."

Under conditions of stress, however, the explicit system sometimes takes over. That's what it means to choke. When Jana Novotna faltered at Wimbledon, it was because she began thinking about her shots again. She lost her fluidity, her touch...

A centipede was happy, quite,
Until an ant, in fun,
Said "Pray, which leg comes after which?"
Which raised his doubts to such a pitch,
He fell befuddled in the ditch,
Not knowing how to run.