Baddeley and Hitch proposed a more complex construct, working memory (WM), that could maintain information in a readily accessible state, consistent with the short-term store (STS), but could also engage in concurrent processing, as well as maintain access to more information than the limited capacity STS could purportedly maintain. Delineating the exact characteristics of WM and accounting for variation in working memory capacity (WMC) continues to be an extremely active area of research. Various measures of WMC have been shown to correlate quite strongly with measures of intelligence, accounting for at least half the variance in fluid intelligence (gf). The multi-mechanism view of the relationship between WMC and gf also has implications for research on WM training and for cognitive therapy for the elderly and patients with neural damage or disease. WMC is strongly correlated with gf.