"Furthermore, general and specific switch costs formed distinct empirical entities (i.e. latent factors) that generalized across stimulus materials. General and specific switch costs did not disappear after large amounts of practice and with long RSI, suggesting that both facets of cognitive control behaviour seem to reflect basic components (biological constraints) of the cognitive system. Furthermore, young and old adults were able to improve cognitive control functioning with increasing practice and to prepare the cognitive system in advance with long RSI.
In line with the theoretical consideration that both cognitive control measures represent mechanic components, both general and specific switch costs were more negatively related to reasoning and perceptual speed from the fluid-mechanic domain of intelligence than to knowledge from the crystallized-pragmatic domain."
"Taking into account that older adults show generally slower performance compared to younger adults, negative age effects were significantly more pronounced in general switching ability than in specific switching ability. The extent to which both cost measures represent valid indicators of cognitive control, this finding indicates that the ability to maintain and coordinate taskrelevant information during task switching was more affected with advancing age than the ability to initiate and execute a task switch ..."