Theory of Constancy of Intelligence

"mental age" (MA). The MA expresses the existing status of the intelligence in terms of the age level whose normal status the individual has reached. The IQ, however, relates the MA of an individual to his chronological age (CA) :IQ = MA/CA. On each age level, this value must be = 1 with reference to normal intelligence. For intelligence below normal we have < 1 and above normal > 1. The question whether, and in what sense, it is possible to speak of such an intellectual quantitative constant is of no slight theoretical importance; the further question whether the above mentioned value proves to be empirically constant to such an extent as