Why? Draw the line backwards, and in a couple of decades you are down at 0 IQ. That's clearly absurd, you can't draw any conclusions of IQ significantly before 1950 from how the line behaves after 1950.

▲

cluckindan 4 hours ago | parent [-]

And that’s because IQ is a statistical distribution, not an absolute measurement of intelligence.

If everyone suddenly gets twice as smart as before, nobody’s IQ changes.

	▲	anamexis 4 hours ago \| parent \| next [-]
		For any given IQ test, the norming sample is taken once. So if everyone gets twice as smart as before, everyone's IQ, as measured by any existing IQ test, would go up.
	▲	jibal 31 minutes ago \| parent \| prev \| next [-]
		This is wrong and confused in every possible way. Look up the Flynn effect ... it refers to an actual change in performance. That the scores on a given IQ test are occasionally renormalized so that the mean is 100 has no bearing on whether "IQ is a statistical distribution", whether intelligence or whatever the heck IQ measures can be measured absolutely, or on the validity and meaning of the previous statements by Epa095, sokoloff, and irdc and why they are or are not true. If everyone suddenly gets twice as smart as before, all of their IQs will shoot up until the scoring of every IQ test is renormalized to a mean of 100.
	▲	readthenotes1 4 hours ago \| parent \| prev [-]
		True, but irrelevant. Or, false and irrelevant. People's scores on yesteryear's tests rose over the distribution when the test was initially taken.