“All models are wrong; some models are useful.”
There's a single component responsible for almost half of the difference: https://en.m.wikipedia.org/wiki/G_factor_(psychometrics)
>It is a variable that summarizes positive correlations among different cognitive tasks, reflecting the fact that an individual's performance on one type of cognitive task tends to be comparable to that person's performance on other kinds of cognitive tasks.
It's useful to put it into one dimension though because all those different scores are quite correlated. A well functioning brain is usually generally just good at many different things.
They could just be out to sell books though, too; I don't have a strong opinion either way.
Perceptions of intelligence are variable to practice and preparation if the measure is nonrandomized convergent standardized tests, which is not IQ but is the more accepted assessment of intelligence. IQ only seems to matter up to 135 after which other factors become more dominant in determining success.
I look at it like this, for creative, intellectually demanding work IQ is a necessary but perhaps insufficient condition. You need to be smart to achieve success cause you are competing with other people, so smarter people will have an edge. Google is not hiring people with 90-110 iqs. So having a high IQ is needed to at least be sufficiently proficient in coding, to be considered for a good paying job, but not guarantee you will be hired, but being smart sure helps.
Should I even bother on what's the source of this claim?
> Can You Ever Be Too Smart for Your Own Good? Comparing Linear and Nonlinear Effects of Cognitive Ability on Life Outcomes > Despite a long-standing expert consensus about the importance of cognitive ability for life outcomes, contrary views continue to proliferate in scholarly and popular literature. This divergence of beliefs presents an obstacle for evidence- based policymaking and decision-making in a variety of settings. One commonly held idea is that greater cognitive ability does not matter or is actually harmful beyond a certain point (sometimes stated as > 100 or 120 IQ points). We empirically tested these notions using data from four longitudinal, representative cohort studies comprising 48,558 participants in the United States and United Kingdom from 1957 to the present. We found that ability measured in youth has a positive association with most occupational, educational, health, and social outcomes later in life. Most effects were characterized by a moderate to strong linear trend or a practically null effect (mean R2 range = .002–.256). Nearly all nonlinear effects were practically insignificant in magnitude (mean incremental R2 = .001) or were not replicated across cohorts or survey waves. We found no support for any downside to higher ability and no evidence for a threshold beyond which greater scores cease to be beneficial. Thus, greater cognitive ability is generally advantageous—and virtually never detrimental. https://www.gwern.net/docs/iq/2021-brown.pdf
It is most explanatory at the low end; Cognitively Challenged. Elsewhere it has a correlation it is just not as significant, which is not in conflict with your link.
If you tested all the Children in the US you aren't going to be able to accurately rule out 84% of them from professional careers by IQ.
https://4.bp.blogspot.com/-4b8ThyfDgzs/U29nQEBAQTI/AAAAAAAAE...
https://en.wikipedia.org/wiki/Study_of_Mathematically_Precoc...
https://my.vanderbilt.edu/smpy/
The obvious question is, if IQ (or whatever SAT is measuring) is irrelevant, why is it so predictive of lifetime academic output?
Also, people try to attack the SAT as nothing more than test prep - but I don't think that argument works well because it supposes you can produce kids who score 700 on the math SAT before age 13; such a training program has never been observed.
NB: SMPY qualifications for at least the early cohorts of the study are “before 13” (so, 12 or younger).
> Can You Ever Be Too Smart for Your Own Good? Comparing Linear and Nonlinear Effects of Cognitive Ability on Life Outcomes
> Despite a long-standing expert consensus about the importance of cognitive ability for life outcomes, contrary views continue to proliferate in scholarly and popular literature. This divergence of beliefs presents an obstacle for evidence- based policymaking and decision-making in a variety of settings. One commonly held idea is that greater cognitive ability does not matter or is actually harmful beyond a certain point (sometimes stated as > 100 or 120 IQ points). We empirically tested these notions using data from four longitudinal, representative cohort studies comprising 48,558 participants in the United States and United Kingdom from 1957 to the present. We found that ability measured in youth has a positive association with most occupational, educational, health, and social outcomes later in life. Most effects were characterized by a moderate to strong linear trend or a practically null effect (mean R2 range = .002–.256). Nearly all nonlinear effects were practically insignificant in magnitude (mean incremental R2 = .001) or were not replicated across cohorts or survey waves. We found no support for any downside to higher ability and no evidence for a threshold beyond which greater scores cease to be beneficial. Thus, greater cognitive ability is generally advantageous—and virtually never detrimental.
Sure, a smart introvert can learn how to act like an extrovert. But this will never be natural to him and will cause an additional cognitive load.