Definition of Fluid Intelligence (Gf)
Fluid intelligence (Gf) is our reasoning and problem solving ability in new situations. It lies behind the use of
deliberate and controlled mental operations to solve novel problems that cannot be performed automatically. Mental operations often include drawing inferences, concept formation, classification, generating and testing hypothesis, identifying relations, comprehending implications, problem solving, extrapolating, and transforming information. Inductive and deductive reasoning are generally considered the hallmark indicators of Gf. Gf has been linked to cognitive complexity which can be defined as a greater use of a wide and diverse array of elementary cognitive processes during performance. Dr. Kevin S. McGrew
Tests of Fluid Intelligence
Deductive reasoning, inductive reasoning (Matrices), quantitative reasoning, and speed of reasoning.
McGrew, K. S. (2009). Intelligence 37, 1–10.