Gc and Gf are both valid intelligence factors: Commentary on Robinson (2005)

Ashton, 2001, Which is the real intelligence? A reply to Robinson (1999), Personality and Individual Differences, 30, 1353, 10.1016/S0191-8869(00)00117-3 Ashton, 2000, Fluid intelligence, crystallized intelligence, and the Openness/Intellect factor, Journal of Research in Personality, 34, 198, 10.1006/jrpe.1999.2276 Deary, 1998, A triarchic theory of Jensenism: persistent, conservative, reductionism, Intelligence, 26, 273, 10.1016/S0160-2896(99)80011-7 Jackson, 1984 Ozer, 1985, Correlation and the coefficient of determination, Psychological Bulletin, 97, 307, 10.1037/0033-2909.97.2.307 Robinson, 1999, The ‘IQ’ factor: Implications for intelligence theory and measurement, Personality and Individual Differences, 27, 715, 10.1016/S0191-8869(98)00271-2 Robinson, 2005, Additional grounds for proposing that the “verbal” or “Gc” factor is the most valid intelligence factor, Personality and Individual Differences, 38, 1715, 10.1016/j.paid.2004.11.005 Wechsler, 2001