Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:…cognitive impairments, for instance in the fields of memory, executive functions and attention, their psychomotor functions showed no discrepancy (Porter et al., 2003).
impliCit learning
Besides working memory, another important component of cognitive functions is implicit learning, which is the…
Category: