Intelligence and brain activation

"According to the neural efficiency hypothesis, differences in intelligence become apparent in the degree of brain activation that occurs during problem solving, i.e., for more intelligent individuals, the correct answer comes with less brain activation than for less intelligent individuals (Haier et al., 1988). This original hypothesis of neural efficiency was introduced in a positron emission tomography (PET) study, the results of which showed less brain glucose metabolism in more intelligent individuals while solving cognitive tasks. Haier and colleagues stated, “Intelligence is not a function of how hard the brain works but rather how efficiently it works … This efficiency may derive from the disuse of many brain areas irrelevant for good task performance as well as the more focused use of specific task-relevant areas” (Haier, Siegel, Tang, Abel, & Buchsbaum, 1992b, pp. 415–416). In addition, with electroencephalography (EEG), it was shown that event-related desynchronization (ERD) in the upper alpha band, considered an index of cortical activation (Klimesch et al., 1997 and Pfurtscheller and Aranibar, 1977), is negatively related to intelligence (for a review, cf. Neubauer & Fink, 2009). However, although the neural efficiency hypothesis has often been confirmed, moderating factors have been identified, in particular, task difficulty and practice or learning (Neubauer & Fink, 2009)."

Evolution is smart.

http://www.sciencedirect.com/science/article/pii/S0160289615000513