Rich Shiffrin (1942- ) a cognitive scientist at Indiana University (USA) and Wolfgang Schneider (1950-) professor of psychology at the University of Würtzburg (Germany) conducted a series of experiments which provide support for two types of cognitive performance.
Controlled processing uses short-term memory and involves the ad hoc creation of temporary routines to provide a flexible response to a novel situation. Automatic processing, on the other hand, does not use up short-term memory resources, since it operates outside the learner's conscious control and independently of attention.
Controlled processes are automatised through training, Rumelhart and Norman would claim via restructuring.
Read and reflect: U-shaped learning