Every trick has many aspects: foot placement, application of pressure on the right parts of the board, jumping with the board in the direction it moves, timing, clearing the stairs or ledge on which a trick is being performed, etc. When learning a trick I often forget which elements I've already worked on and which still require my attention and end up working on the same elements again and again. Sometimes I forget errors that I've corrected in the past and thereby revert to former mistakes. This makes my manner of learning tricks highly inefficient. Clearly, memory plays an important role in the trick learning process.
People typically conceive of memory as the ability to bring previous experiences to mind. In truth, memory involves much more than that. Psychologists and cognitive scientists divide memory into several forms (though the boundaries between them are often elusive): iconic/echoic memory, working memory, short term memory, and long term memory:
a) Iconic/echoic memory are the impressions of visual or auditory sensations lasting for a few fleeting moments after they're experienced. It is this memory that allows one to perceive a series of actions as one cohesive sequence.
b) Short term memory is the ability to remember ideas from a minute to extended periods, without any ongoing conscious effort to sustain the memories. However, the memories are not so deeply impressed upon the psyche as to become permanent.
c) Long term memory is the ability to store information permanently.
d) Working memory is the capacity to consciously 'hold' information while manipulating it. Working memory can draw on all the other forms of memory. For example, while reading this post your working memory draws on your memories of English reading skills (long term memory), remembers the chain of ideas mentioned earlier in the post so that the present ideas are seen in context (short term memory), and it draws on the sensory impressions of the words being read. To hold ideas in working memory, people often repeat words or concepts in their mind over and over. It has been demonstrated that intelligence strongly hinges on the effectiveness of working memory, for in order to make sense of information one must be able to juggle many ideas/skills within the mind from all levels of memory.
Let's apply these memory types to skateboarding:
When skating, it is necessary to see the sequence of movements involved in a trick's performance as one coherent continuum. This requires firm attention to the iconic/echoic (tactile, vestibular, etc) impressions. Of course, to carry out movements correctly and to sense where in a trick's series of steps one is holding at any given moment one must draw on long term memory of how the trick is performed (or short term memory if the trick still hasn't become ingrained). One may then compare present performance with one's memory of how the trick should be performed.
Working memory allows one to keep both memory types in mind for the comparison to be made. When one finds a discrepancy between the two memory types, it may be that either one's present performance requires correction so that it aligns with long term memory, or that long term memory requires modification. Alternatively, both memory types may require improvement. One's 'theories' of what requires correction and why must be kept in mind in order that their merit be tested. Short term memory offers the storage needed for the theories.
Memory can also work at a subconscious level. In one relevant study, a group of people were shown a list of names famous only in highly specialized circles. Several months later they, alongside another group that hadn't been shown the list of names, were shown another list of names and asked to identify the prominent ones. Some of the names on the second list appeared on the first list. The group exposed to the first list were remarkably more capable of identifying prominent names even though they'd long forgotten the names from the first list. They seemed to remember names from the first list subconsciously.
This has promising implications for skateboarders who feel that a lack of any obvious progress renders a skate session a waste of time. For during every session one subconsciously assimilates information and experiences which transfer as subconscious memory to subsequent skating. A skater thus continues to progress even when unaware of the memories underlying his growth...