High individual alpha frequency brains run fast, but it does not make them smart
Michał Ociepka, Patrycja Kałamała, Adam Chuderski
Abstract
Evidence for the relationship between individual alpha frequency (IAF) and cognitive ability (general intelligence) is inconclusive, and the role of alpha rhythm in shaping cognition is hotly debated. This study aimed to provide more conclusive evidence. EEG was recorded during three resting state sessions, a vigilance session, and a short-term visual memory task. Six respective IAF estimates were calculated for a total of 153 participants. Participants also completed the battery of 17 tests measuring four main dimensions of cognitive ability: fluid reasoning, working memory, visual discrimination, and processing speed. Confirmatory factor analysis indicated that the factors reflecting fluid reasoning, working memory, and visual discrimination, as well as the higher-order factor reflecting general intelligence, were unrelated to the IAF factor. At the same time, IAF positively correlated with processing speed, sharing 5.5% of variance. The EEG findings were replicated in another sample (N = 94) using MEG data and a different cognitive-ability assessment. Overall, the study implies that brains with higher IAFs do run faster, but it does not make them smarter. The study clarifies the so far equivocal relationship between the individual frequency of the dominating alpha rhythm and cognitive functioning.