Multiplying memory span by mental speed, we obtain the entropy of short-term memory capacity, which is rate-limiting for performance in intelligence tests. Information entropy can also be calculated by using the entropy formula for quantum particles (bosons), in which case memory span becomes the quantum number n. The first harmonic of the cavity resonator brain is the eigenfrequency π; and entropy can be expressed as n 2 π ( n = 1,2,…,9). The fact that high IQ subjects exhibit a greater complexity of EEG follows from the quantum number increase for the wave function with the result of higher brain power for Fourier transformation of information. Such individual differences in general intelligence are caused by differences in brain energy metabolism. Consequently, cerebral glucose metabolism rate and IQ have been found highly correlated. The responsible regulatory mechanism of oscillatory glycolysis is redox control by thiol disulphide exchange in which the genetic polymorphism of glutathione peroxidase plays a key role.