Damian Birney, David Bowman, and Gerry Pallier in their Behavioral and Brain Science commentary on Clancy Blair’s ‘How similar are fluid cognition and general intelligence? A developmental neuroscience perspective on fluid cognition as an aspect of human cognitive ability‘ (2006, BBS, 29, 109-160 – link here) make the following excellent point:

“The gF (fluid intelligence) – working memory – executive function  issue is a further case in point. gF has developed meaning from within the psychometric domain, where it is common to define constructs not only by what they are, but also by what they are not. Hence, using factor-analytic techniques, gF has been empirically defined as the latent trait extracted from a variety of reasoning-dominated tests. This gF trait is related to, but empirically (and therefore theoretically) distinct from, the gC latent trait, which is similarly extracted from various tests of (typically verbal based) acculturated knowledge.

WM (working memory) theory was developed within the cognitive-experimental paradigm, mostly using dual-task methodologies to dissociat various storage and processing systems.

EF (executive function) has a more recent history and has been endorsed most actively by cognitive neuropsychology.

The tasks used in these related, yet distinct, research programs have been developed with different purpose in mind.”