Noun
mental ability
Source: WordNetI have long held the opinion that the amount of noise that anyone can bear undisturbed stands in inverse proportion to his mental capacity and therefore be regarded as a pretty fair measure of it. Arthur Schopenhauer
I know I have the mental capacity of a thousand bloggers, but because of that, my obligation to serve God is also that of a thousand bloggers. Mickey Kaus
W. L. Mackenzie (Canada West/Ontario Leader of 1837 Rebellion) – "He is every whit a self-made, self-educated man. Has large mental capacity and indomitable energy.”. Alexander Mackenzie
Mental attitude is more important than mental capacity. Walter Dill Scott
he's got plenty of brains but no common sense Source: Internet
An elderly and longtime Portuguese employee who worked as a bookkeeper and clerk for the firm, in his latter years with the firm, had frequently been committing serious errors in the firm's books and his mental capacity was deteriorating. Source: Internet