According to the temporal resolution power (TRP) hypothesis, individual differences in mental ability (MA) can be explained by differences in the neural oscillations of the central nervous system which find expression in the acuity of temporal information processing: Faster neural oscillations do not only lead to better temporal information processing but also to faster speed of information processing and to better coordinated mental operations which, in turn, lead to higher MA. Empirical evidence for this hypothesis is reviewed in this chapter. Also, critical findings challenging the TRP hypothesis are compiled. For example, it is not yet clear whether the relations of MA to temporal and non-temporal discrimination ability can be dissociated from each other. In addition, the role of attention as a possible underlying mechanism of the relation between TRP and MA needs further exploration.